BIO FINAL

1. What are the main parts of a virus?

protein coat and nucleic acid core

cannot reproduce on their own

are specific and only multiply in certain hosts Viruses occur as obligate intracellular parasites in all types of cells (Obligate intracellular parasite: parasite that can only reproduce itself inside of a host cell by taking over the host’s cellular machinery) \n 2. How are hosts important in viral replication?

a virus cannot replicate by itself. they must enter a host cell and use the host’s biosynthetic machinery to make more copies of themselves \n 3. What is a bacteriophage?

Binal virus: has elements of the icosahedral and helical structures

(Icosahedron: has a soccer ball shape; most animal viruses have this shape)

(Helical: rodlike or threadlike) \n 4. Distinguish between the lytic cycle and lysogenic cycle in bacteriophages.

Lytic cycle:

• Attachment: attachment of virus onto host cell provided the virus can chemically recognize and lock onto specific groups on the cell’s surface
• Penetration: either whole virus or the genetic material from the virus enters host cell’s cytoplasm
• Replication and Synthesis: “Molecular piracy” --DNA or RNA directs the host cell to make many copies of viral components
• Assembly: Viral nucleic acids and viral proteins are assembled into new viruses
• Release: host cell bursts to release new virus particles (Lysis of the host cell releases virus particles)

Lysogenic Cycle:

• Viral DNA is integrated into bacterial chromosome
• Bacterium replicates all DNA including that of virus
• After binary fission, each daughter cell has chromosome with viral DNA incorporated
• later, some molecular signal or other stimulus may reactivate the viral DNA. Then, it goes through lytic cycle

5. What type of virus is HIV? What disease does it cause? How does HIV compromise the immune system?

HIV is a retrovirus

HIV causes AIDS but is closely-related to SIV

HIV targets CD4+ cells, particularly T-Helper cells

T-Helper cells are responsible for mounting a defense against invading bacteria or viruses

AIDS compromised persons are susceptible to opportunistic infection

(Opportunistic infection: Healthy people can fight these off, but the immune-compromised person cannot)

6. New vaccines are made each year to combat the influenza virus. Explain.

Vaccines are difficult to make effective because viral recombination is greater problem than mutations.

3-4-5 strand antidotes are put in the vaccine to combat the estimated most common strands of the virus

7. What are emerging viruses?

Emerging Viruses: Viruses that originate in one organism and then pass to another and cause disease

8. How do viruses cause cancer?

Viruses can trigger oncogenes to become active

viruses may also carry and integrate oncogenes into host cells’ genome

Possibly 15% of human cancers are caused by viruses

Chronic Hep B → liver cancer

HPV → cervical cance

9. What are prions? What kinds of diseases are caused by prions?

Prion replication: prions are proteinaceous infectious particles consisting of a misfolded form of a protein

• misfolding causes chain reaction of misfolding of normal proteins resulting in disease
• prions may cause TSEs

10. What are viroids? What kinds of diseases are caused by viroids?

Viroids: infectious RNA with no protein coat

viroids infect plants and use host protein to replicate

11. What are the features of prokaryotic cells?

• unicellular
• 0.5-5 micrometers or less in diameter
• small circular DNA
• divide by binary fission
• no internal compartmentalization
• no membrane-bound organelles
• singular flagellum
• metabolic diversity: can use energy stored in chemical bonds of inorganic molecules to synthesize carbohydrates

12. What types of organisms are in the domain Archaea?

many archaea are extremophiles

• thermophiles
• halophiles
• methanogens

13. Distinguish between gram-positive and gram-negative bacteria.

Gram-positive: thicker peptidoglycan wall, stains purple

Gram-negative: less peptidoglycan; red counter dye results in dark pink color

14. What are the three basic forms or shapes of prokaryotes?

Prokaryotic cell structure; three basic forms

• rod-shaped
• cocci
• spiral

BACTERIAL CELL WALL IS THE SINGLE MOST IMPORTANT CONTRIBUTOR TO CELL SHAPE

15. What are plasmids? How are they involved with conjugation?

Plasmids: accessory DNA molecules

Antibiotic resistance can be transferred by resistance plasmids

conjugation is horizontal gene transfer

16. What is transduction?

transduction: DNA exchange with a method that uses viruses

17. What is transformation?

transformation: DNA exchange by bacteria picking up genetic material from environment

18. Distinguish among: photoautotrophs, chemoautotrophs, photoheterotrophs, chemoheterotrophs.

Photoautotrophs: photosynthetic bacteria (cyanobacteria)

Chemoautotrophs: Oxidize inorganic compounds (nitrifiers)

Photoheterotrophs: use light as source of energy but obtain carbon from organic molecules (purple and green nonsulfer bacteria)

Chemoheterotrophs: obtain both carbon and energy from organic molecules (majority of prokaryotes including decomposers and most pathogens)

Humans and all nonphotosynthetic eukaryotes and chemoheterotrophs too

19. How are prokaryotes involved in cycling important elements such as carbon and nitrogen?

Prokaryotes aid in fixation: return elements from the inorganic form to organic forms that heterotrophs use

Carbon fixation: involves incorporating the carbon from CO2 into complex organic compounds

Nitrogen fixation: involves certain bacteria converting N2 gas to ammonia and then to nitrate

20. How are bacteria used in genetic engineering?

Bacteria are used in the production of pharmaceutical agents such as insulin

Bacteria are also used in the production of enzymes, vitamins, and antibiotics

Bacteria can be used in production of commercial acetone and other industrial compounds

21. How are bacteria used in bioremediation?

Bacteria are used in bioremediation for:

• sewage treatment plants
• cleaning up oil spills
• removal of contaminants from ground water

22. What are the features of eukaryotic cells?

23. Describe the theory of endosymbiosis?

Endosymbiosis theory: mitochondria probably evolved from aerobic bacteria that were engulfed by a larger cell

Endosymbiosis theory: Chloroplasts/plastids probably evolved from photosynthetic bacteria that were engulfed (secondary endosymbiosis)

24. What are the two main means of locomotion used by protists?

Protists move by flagella or cilia and pseudopodia (axopodia, filopodia)

25. What are the distinguishing features or characteristics of the following protists? Give examples of each. Diplomonads, Parabasalids, Euglenoids, Kinetoplastids, Dinoflagellates, Apicomplexans, Ciliates, Stramenopila, Rhodophyta, Choanoflagellates, Amoebas

Diplomonads:

• two nuclei
• unicellular
• move with multiple flagella
• modified mitochondria called mitosomes

Ex. Giardia intestinalis: causes diarrhea (found in contaminated water and can pass from human to human)

Parabasalids:

• undulating membranes
• move with flagella
• reduced mitochondria called hydrogenosomes

Ex. Trichonympha species (lives in gut of termites and digests cellulose) and trichomonas vaginalis (STD in humans)

Euglenoids:

• mitochondria
• flexible pellicle can change shape
• 1/3 of euglenoids have chloroplasts and are fully autotrophic (may become heterotrophic in dark)
• some lack chloroplasts and are heterotrophic
• reproduce by mitosis
• no sexual reproduction is known

Ex. Euglena: photosynthetic

Kinetoplastids:

• unique, single mitochondrion in each cell
• evade immune response with a “bait-and-switch” defense; surface proteins are changed frequently
• trypanosomes are disease-causing

Ex. African sleeping sickness (transmitted by tsetse fly), Leishmaniasis (transmitted by sand fly), and chagas diseased caused by Trypanosoma Cruzi (small wild mammals carry the parasite

Dinoflagellates:

• photosynthetic unicells
• have two flagella located in grooves in cellulose plates
• both marine and freshwater
• some are luminous
• “red tides” result from “blooms” of dinoflagellates
• “red tides” are detrimental to fishing industry
• produce powerful toxin that inhibits diaphragm causing respiratory failure in vertebrates
• abundance of toxic dinoflagellates may result in death of marine mammals, fish, and birds
• dinoflagellates reproduce primarily by asexual reproduction

Apicomplexans:

• spore-forming parasites of mammals
• have apical complex of organelles, vacuoles, fibrils, microtubules at one end of cell

Ex. plasmodium causes malaria (transmitted by the anopheles mosquito)

Ciliates:

• have many numbers of cilia arranged in longitudinal rows or spirals
• some cilia may be fused into sheets, spikes, or rods that function as mouths, paddles, teeth, or feet
• have a pellicle
• unicellular heterotrophs
• micronucleus may only be needed for sexual reproduction
• macronucleus divides by mitosis and is involved with physiological function
• vacuoles for ingesting food and maintaining water balance
• conjugation involves exchange of micronuclei

Stramenopila: protists with fine hairs (brown algae, golden algae, diatoms, and oomycetes)

brown algae:

• most conspicuous seaweeds in northern regions (kelps)
• thallus = blade, stipe, holdfast
• algin = gel-forming substance used to thicken puddings and salad dressings
• undergoes alternation of generations sporophyte (diploid) goes through meiosis to produce spores, gametophyte are smaller, filamentous individuals
• kelp doesn’t have complex tissues such as xylem that are characteristics of plants

Golden algae:

• biflagellated
• freshwater or marine
• all are photosynthetic; some mixotrophic
• most are unicellular; some colonial
• many species can form protective cysts if environmental conditions deteriorate

Diatoms:

• unicellular
• photosynthetic
• double shells (look like a box with lid)
• made of opaline silica
• live diatoms can withstand great pressures
• vibrating fibrils line grooves
• diatomaceous earth - filtering medium

Oomycetes: (water molds)

• all are parasites or saprobes
• used to be categorized as fungi
• have motile spores (zoospores) with two unequal flagella
• zoospores produce asexually
• sexual reproduction via male and female gametes
• most oomycetes live in water, but terrestrial forms are plant pathogens

Ex. phytophthora: causes late blight of potatoes (Irish potato famine) and Saprolegnia: fish pathogen (can infect amphibians and kill amphibian eggs)

Rhodophytes: red algae

• no centrioles
• no flagella
• reproduce by alternation of generations
• produce pigments that give them a red color

Ex. Porphyra: Japanese “nori” used to wrap sushi

Choanoflagelates:

• most like the common ancestor of sponges
• have single flagellum surrounded by collar of shorter filaments
• feed by straining bacteria from water with their collar

Amoebozoans include slime molds, gymnamoebas, and entamoebas

true amoebas

• pseudopodia that are lobe- or tube-shaped
• microfilaments of actin and myosin
• amoebas can move in any direction

slime molds:

• originated at least 3 times and used to be grouped with fungi

• plasmodial slime molds:

  • multinucleate, moving mass of cytoplasm = feeding phase
  • usually yellow or orange in color
  • feed on bacteria, yeast, and other organic matter
  • undergoes synchronous mitosis
  • form sporangium under adverse conditions

• cellular slime molds

  • individuals act like amoebas
  • eat bacteria
  • if food is scarce, they aggregate to form a moving “slug”

Tubulinids (used to be Gymnamoebas):

• large and varied group of amoebas
• free living
• found in soil, freshwater, and saltwater
• heterotrophs that feed on bacteria, other protists, and detritus

Entamoebas:

• parasites of vertebrates and some invertebrates

Ex. E. histolytica: causes amebic dysentery (spread via contaminated food, water, or eating utensils) and may sometimes get to brain and cause abscesses

26. Describe the life cycle of Plasmodium.

27. What are red tides?

blooms of dinoflagellates which are detrimental to fishing

28. Describe the life cycle of Paramecium.

29. What diseases are caused by “water molds” (oomycetes)?

Phytophthora infestans: causes late blight of potatoes

terrestrial oomycetes are plant pathogens

saprolegnia is a fish pathogen

30. Describe the evolutionary significance of the choanoflagellates.

31. How do amoebas move?

32. Of what are the White Cliffs of Dover composed?

fossils created by limestone deposits

33. Distinguish between a sporophyte and a gametophyte.

sporophytes are diploid generation goes through mitosis to produce spores

gametophytes are small filamentous individuals

• sporophyte is diploid generation
• gametophyte is haploid generation

Gametophyte generation is more prominent in mosses, liverworts, and ferns.

Sporophyte generation is more prominent in gymnosperms and angiosperms.

34. Describe a generalized multicellular plant life cycle.

Haplodiplontic cycle produces alternation of generations. (See Fig. 29.5 on p. 620)

​**•  sporophyte is diploid generation**

​**•  gametophyte is haploid generation**

35. What are unique features of bryophytes? Give examples of bryophytes?

Byrophytes: closest living descendants of the first land plants. they include liverwarts, mosses, and hornworts

Bryophytes are nontracheophytes; they have no tracheids.  They do have other conducting cells for moving water and nutrients.

Many bryophytes have mycorrhizal associations = symbiotic relationship between fungi and plants.

36. What are the functions of xylem and phloem?

xylem: conducts water and minerals from roots

Phloem: conducts sucrose and hormones

37. What are the functions of stems, roots, leaves, and seeds?

Stems evolved before roots did.

Roots provide structural support and transport capability.

Leaves evolved more than once.

​**•  Lycophytes – no vascularization in** ​   ​   leaves

​**•  Ferns and seed plants have true leaves**

Seeds are another innovation in some phyla.

​**•  protects embryo from drying out**

​**•  protection from predators (somewhat)**

38. What kind of plants are lycophytes?

Lycophytes: dominant sporophyte generation and vascular tissue

• earliest land plants
• first plants to have a dominant sporophyte generation

39. The pterophytes include whisk ferns, horsetails, and ferns. What are some of the novel features of each?

pterophytes:

• recent molecular evidence suggests the three groups (horsetails and whisk ferns) make up one clade and are now treated as one phylum Monilophyta
• monilophytes require water for fertilization and are seedless

Whisk ferns lost their roots and leaves secondarily.

Horsetails have jointed stems with brushlike leaves.  The stems have silica deposits in epidermal cells of their ribs.

Ferns have fronds that bear sori.

​**•  Sori are sporangia located on underside** ​  ​   **of fern fronds.**​

​**•  Gametophyte is heart-shaped and can** ​ ​   ​   live independently.

40. What are the evolutionary advantages of seeds?

Seeds are another innovation in some phyla.

​**•  protects embryo from drying out**

​**•  protection from predators (somewhat)**

Seed plants originated approximately 360 mya.

Seed = embryo and its food supply surrounded

​ by a protective coat

​**•  seeds can move away from mother plant**

​**•  seed plants are dominant producers on**

​land

​**•  12,000 years ago humans began** ​cultivating plants

Seeds and pollen grains are key adaptations for life on land

​Five derived traits of seed plants:

1. Reduced gametophytes

​microscopic male and female ​gametophytes (n) are nourished and ​protected by the sporophyte (2n)

2)  Heterospory

​microspore (gives rise to a male ​gametophyte)

​megaspore (gives rise to a female ​      gametophyte)

3. Ovules

​inside each ovule, a female gametophyte

​develops from a megaspore and

​produces one or more eggs

4. Pollen

​pollen grains make water unnecessary

​for fertilization; pollination occurs when

​pollen is transferred to the part of the

​seed plant that contains the ovules

5. Seeds

​survive better than unprotected spores;

​can be transported long distances (by

​wind or animals)

41. Identify the structures known as the male gametophyte and the female gametophyte.

Reduced gametophytes

​microscopic male and female ​gametophytes (n) are nourished and ​protected by the sporophyte (2n)

Heterospory

​microspore (gives rise to a male ​gametophyte)

​megaspore (gives rise to a female ​      gametophyte)

42. Describe the distinguishing features of a gymnosperm.

Gymnosperms:  Plants with “Naked Seeds”

*** ovules not completely enclosed in sporophyte tissue at pollination**

43. List the four groups of living gymnosperms.

There are four groups of gymnosperms:

​**•  coniferophytes**

​**•  cycadophytes**

​**•  gnetophytes**

​**•  ginkgophytes**

All gymnosperms lack flowers and true fruits. \n 43. List the four groups of living gymnosperms.

There are four groups of gymnosperms:

​**•  coniferophytes**

​**•  cycadophytes**

​**•  gnetophytes**

​**•  ginkgophytes**

All gymnosperms lack flowers and true fruits.

44. List the defining features of angiosperms.

Angiosperms:  The Flowering Plants

There are more than 250,000 known species of angiosperms.  Their defining characteristics are:

​1)  enclosed ovules within diploid tissue

​     at the time of pollination

​2)  produce fruit (from the carpel)

Angiosperm origins are a mystery.

​**•  Archaefructaceae (extinct family) may** ​ ​   ​   be sister clade, but debate continues.

​**•**  Amborella trichopodathought to be ​  ​​   ​  closest living relative to the first ​  ​   ​   ​   angiosperm \n 45. Describe the roles of some animals in the angiosperm life cycle.

Fruits allow angiosperms to colonize large areas.

​a)  Fruits with fleshy coverings that are

​black, blue, or red are usually ​dispersed by birds or vertebrates.

​The seeds of these fruits have a hard

​seed coat that is resistant to stomach

​acid or digestive enzymes.

​b)  Fruits with hooked spines (burrs) are

​dispersed on animal fur or humans’

​clothing.

​c)  Squirrels and other mammals bury ​acorns or other nuts that may sprout

​in the spring.

​d)  Fruits of maple, ash, and elm trees ​have “wings” that aid in wind dispersal.

​e)  Orchids have dustlike seeds that are

​wind-blown.

​f)  Dandelions have seeds with ​    “parachutes” that float on wind currents.

​Milkweeds, cottonwood trees, willows,

​goat’s beard, and others have similar

​adaptations for wind dispersal.

​g)  Coconuts can float in water for ​dispersal to another island. \n 46. Explain double fertilization and its outcome.

Angiosperm life cycle includes double fertilization.  (See 30.12 on p. 646)

​**•  Megaspore produces 8 haploid nuclei.**

​**•  Female gametophyte consists of embryo sac and the 8 nuclei in only 7 cells.**

​**•  Most important are the egg and the two**

​   polar nuclei in the single cell.

​**•  Pollen grain (after landing on receptive** ​   ​   stigma) forms pollen tube toward ​ ​  ​   ​   embryo sac.

​**•  Two sperm pass through the tube.**

​**•  One fuses with egg to form zygote.**

​**•  Other sperm fuses with polar bodies to** ​  ​   form triploid endosperm nucleus.

​**•  Endosperm will nourish the embryo.** \n 47. What are the characteristics that distinguish fungi from other eukaryotes?

Fungi are more closely related to animals than to plants. Cell walls of fungi contain chitin – the same material found in the exoskeletons of arthropods. \n 48. Define: hyphae, mycelium, spores.

Fungal cells may have more than one nucleus.

​**•  monokaryotic (septate) = hypha with one** ​nucleus

​**•  dikaryotic = hypha with two nuclei**

​**- heterokaryotic = nuclei from two**

​    ​   genetically distinct individuals

​**- homokaryotic = nuclei from** ​        genetically similar individuals

​**•  coenocytic = hypha made up of a** ​  ​  ​ ​         continuous cytoplasmic mass with ​   hundreds or thousands of nuclei

The body of a fungus is a mass of connected hyphae called a mycelium.

Spores can form asexually or sexually and are most often dispersed by the wind. \n 49. How do fungi absorb nutrients?

Fungi are heterotrophic.  They excrete enzymes for external digestion and then absorb the digested products. (saprobic) \n 50. Distinguish among the zygomycota, basidiomycota, and ascomycota. Give examples of each.

Zygomycota:  Fungi That Produce Zygotes

Rhizopus is commonly found growing on moist bread or fruit.  This zygomycete feeds on simple sugars.  (See Fig. 31-12 on p. 660)

Zygomycota is named for the characteristic diploid zygote nuclei they produce.

Basidiomycota:  The Club (Basidium) Fungi

Basidiocarp = visible reproductive structure

Examples include mushrooms, toadstools, puffballs, shelf fungi (breakdown lignin in wood).

Ascomycota:  The Sac (Ascus) Fungi

Ascomycetes make up about 75% of known fungi.  Examples are bread yeasts, common molds, morels, cup fungi, and truffles.  This phylum also includes plant pathogens such as those that cause chestnut blight and Dutch elm disease.  Genus Penicillium is also found in phylum Ascomycota.

\n 51. What is Rhizomes?

Rhizopusis commonly found growing on moist bread or fruit.  This zygomycete feeds on simple sugars.  (See Fig. 31-12 on p. 660) \n 52. Describe the living components of a lichen.

Lichens can live in very harsh habitats.  They are usually the first to colonize an area.  They break down rocks and help prepare for the invasion of other organisms.

Lichens produce very bright pigments, some of which are used as dyes.

Some lichens are used to indicate air quality since they can absorb substances dissolved in rain and dew.  Few lichens are found in or near cities.  As pollution decreases, lichen populations increase. \n 53. What are mycorrhizae? How are they important?

Mycorrhizae are fungi associated with roots of plants.  (Mycorrhizae means “fungus root”)

​**•  fungal hyphae increase amount of** ​              ​   contact with soil and increase surface ​   ​   area for absorption

​**•  haustoria = specialized hyphae used to** ​ ​   extract nutrients from, or exchange ​ ​ ​  ​   nutrients with their plant hosts

​**•  mycorrhizae aid in direct transfer of** ​  ​   ​   phosphorus, zinc, copper, and other ​  ​   ​   minerals from soil into plant roots

​**•  arbuscular mycorrhizae = grow within** ​​   ​   the outer cells of the plant root

​**•  ectomycorrhizae = surround root cells** ​   ​   but do not penetrate them \n 54. Give some examples of how fungal parasite or pathogens harm plants and animals.

Fungal infestation can harm plants and those who eat them.

​**•**  Fusarium grows on spoiled food; ​  produces vomitoxin that can cause brain ​   damage in humans and animals in SW ​   United States

​**•  Aflatoxins are very carcinogenic;** ​​   produced by Aspergillus flavus strains ​​   growing on corn, peanuts, cotton seed

​**•  Aflatoxins can damage kidneys and** ​​   nervous system of animals and humans.

​**•  Aflatoxins have been considered as a** ​​   possible bioterrorism agent.

​**•  Corn smut damages corn, but is not** ​​   harmful to animals that consume it.

​**•  Ergot (fungus associated with rye and** ​​   other cereal grains).  An alkaloid toxin is ​  produced and if eaten can cause ​  ​  ​   hallucinations, gangrene, nervous spasms, burning sensations.  (Ergot implicated in Salem witch trials).  Lysergic acid has been isolated from ergot and is raw material used to make LSD.

Fungal infections are difficult to treat in humans and other animals owing to the similarities between the two kingdoms.

Examples of fungal diseases include:

​**•  ringworm**

​**•  athlete’s foot**

​**•  nail fungus**

​**•  thrush**

​**•  oral or vaginal infections caused by** ​  ​  ​   Candida

​**•**  Pneumocystis jiroveci invades lungs

​**•  mold allergies**

​**•**  Stachybotris causes “sick” buildings

​**•  chytridiomycosis affects amphibians** \n 55.Review Section 32.1 on pp. 674-675 describing the general features of animals.

general features of all animals include:

​**•  heterotrophy**

​**•  multicellularity**

​**•  no cell walls** \n 56. What are the five key innovations in animal evolution? \n  Five key innovations in animal evolution:

​1)  symmetry

​2)  tissues that allow for specialized

​     structures or functions

​3)  body cavity

​4)  various patterns of embryonic ​     development

​5)  segmentation or repeated body units \n 57. Differentiate between a pseudocoelom and a coelom. \n ​ Three body plans for bilaterally ​symmetrical animals.

​1) Acoelomate = no body cavity ​    between digestive tract and muscle ​    layer  (Ex. flatworms)

​2) Pseudocoelomate = have body ​    cavity that develops between ​    mesoderm and endoderm

​    (Ex. roundworms)

​3) Coelomate = body cavity develops ​    entirely within the mesoderm

​    (Ex. annelids) \n 58. What are the differences between protostomes and deuterostomes?

Bilaterians have two main types of development.

​1) Protostome = “first mouth” – mouth ​ ​      develops from the blastopore

​**(Ex. flatworms, nematodes, mollusks,**

​annelids, arthropods)

​2) Deuterostome = “second mouth” – ​ ​    ​      anus develops from the blastopore

​**(Ex. echinoderms and chordates)**

1. Protostomes have determinate ​ ​    ​     development in which the type of ​     tissue that each embryonic cell will​     form is determined early.

​2)  Deuterostomes have indeterminate ​     development in which each cell ​     remains totipotent and each cell’s fate ​     is not determined for several ​     cleavages. \n 59. What are the advantages of segmentation?

Segmentation – the advantages

​1)  efficient and flexible movement

​2)  redundant organ systems \n 60. Compare radial symmetry with bilateral symmetry.

 Most animals exhibit radial or bilateral symmetry.

​**•  Sponges are asymmetrical.**

​**•  Radial symmetry = longitudinal plane**

​   through the central axis divides the

​   animal into two halves that are mirror

​   images of each other (examples are

​   members of phylum Cnidaria)

​**•  Bilateral symmetry= body has right and** ​   left halves that are mirror images of ​  ​   each other (examples are most other ​  ​   animals that are not sponges or ​ ​  ​ ​   cnidarians) \n 61. What is cephalization?

associated with brain, sensory ​     structures such as eyes and ears = ​     cephalization \n 62. Name the three germ layers and identify what body tissues arise from each.

hree germ layers:

​1)  ectoderm (outer layer) gives rise to

​**- outer covering of body**

​**- nervous system**

​2)  endoderm (inner layer) gives rise to

​**- digestive system including** ​   intestines, and organs like liver, ​   ​   and lungs of vertebrates

​3)  mesoderm (middle layer) gives rise ​     to

​**- skeleton**

​**- muscles** \n 63. Distinguish between an open and a closed circulatory system.

Open circulatory system – blood ​   passes from vessels into sinuses, ​   mixes with body fluid that bathes the ​   cells or tissues, and then reenters ​   vessels in another location

​**•  Closed circulatory system– blood is** ​   entirely confined to vessels and is ​   physically separated from other ​   body fluids \n 64. Define: archenteron, blastopore.

archenteron = pouch inside the gastrula; ​opens to the outside via the blastopore

archenteron = “primitive gut”

​**•  blastopore= opening into the** ​archenteron \n 65. Distinguish between spiral cleavage and radial cleavage.

Spiral cleavage – new layer of cells ​ ​     nestles into the space between the ​     older cells  (Ex. annelids, mollusks, ​     nemerteans, other protostomes)

Radial cleavage– pairs of new cells ​    are positioned directly above the older ​     cells (Ex. all deuterostomes) \n 66. Distinguish between determinate and indeterminate development.

​1)  Protostomes have determinate ​ ​    ​     development in which the type of ​     tissue that each embryonic cell will​     form is determined early.

​2)  Deuterostomes have indeterminate ​     development in which each cell ​     remains totipotent and each cell’s fate ​     is not determined for several ​     cleavages. \n 67. Distinguish between the Parazoa and the Eumetazoa.

Metazoa – includes the sponges that do ​not have embryonic germ layers or ​differentiated cells that form tissues

​**Eumetazoa– includes animals that do** ​have embryonic germ layers and ​differentiated cells that form tissues \n 68. \n Review p. 716 on the various animal phyla. Do you remember what some of the keycharacteristics are for these groups?

\n 69. What are the ecdysozoans?

(ecdysozoans) ​ animals  that molt their cuticles at least once ​  ​   during their life \n 70. Describe the different types of cells in the sponge body.

Sponges seem to be mass of cells in

​gelatinous matrix.  There are several cell

​types with specialized functions.  If all the

​cells of a sponge are separated (through a

​fine sieve), the cell types will seek each

​other out and reassemble the entire ​sponge!  No other animal can do this.

​a.  choanocytes = collar cells; function is

​water circulation through sponge and

​capturing, engulfing, and digesting

​food particles

​b.  amoebocytes – distribute nutrients

​throughout the sponge to other cells;

​these are totipotent cells that can

​become other types of cells

​c.  ​pinacoderm – made of flattened cells

​that make up the outer epithelium

​d.  ​porocytes – flattened cells that line the ​pores of the ostia (openings where ​water enters the sponge)

​e.  ​osculum (plural, oscula) = larger ​openings where water exits the ​sponge body

​f.  ​mesohyl = gelatinous, protein-rich

​matrix located between the inner and

​outer layer of cells

​g.  ​spicules = needlelike structures made

​of calcium carbonate or silica

​h. ​spongin = tough protein fibers that

​make up the skeleton of some

​sponges \n 71. What are the defining features of the cnidarians?

  All cnidarians (Phylum Cnidaria) are

carnivores. Most of the 10,000 species are

marine, but a very few live in fresh water.

​**•  diploblastic  (no mesoderm)**

​**•  have tissues, but no organs**

​**•  no reproductive, circulatory, digestive,**

​   or excretory systems

​**•  have a nerve net**

​**•  nematocysts are unique to this phylum** \n 72. Distinguish between the medusa and polyp forms of cnidarians.

Basic Body Plans of Cnidarians

​a)  polyp – typically sessile

​b)  medusa – swims freely in water \n 73. Define: nematocyst, planula, mesoglea.

Nematocysts = microscopic stinging

​capsules  (See Fig. 33.5 on p. 692)

​**•  Capsule everts upon proper stimulation**

​**•  Releases barbs (some have venom too)**

​    that immobilize or kill prey

​**•  Nematocysts only discharged once**

​    (can’t be reused)

egg + sperm → zygote → planula larva ​     → polyp

Two-layered body wall made up of

​    epidermis and gastrodermis with an

​    acellular mesoglea (“middle glue”)

​    between these. \n 74. Identify the five classes of cnidarians.

​1)  Class Anthozoa (“flower animals”)

​     • include sea anemones and corals that

​ exist as solitary or colonial polyps

​     • form economically important coral

​ ​  reefs

​2)  Class Cubozoa = box jellies

​**•  medusa stage dominant; polyp is** ​   reduced or unknown in many cases

​**•  strong swimmers and voracious**

​    predators of fish

​**•  has poison stronger than cobra** ​   venom

​**•  some have image-forming eyes**

​3)​Class Hydrozoa = the hydroids

​**•  both polyp and medusa stages in life**

​    cycle (with some exceptions)

​**•  only class with freshwater members**

​**•  some marine hydroids and medusae**

​    are bioluminescent

​**•  Portuguese man-of-war = floating**

​    colony of highly integrated polypoid

​    and medusoid individuals the stings

​    of which can kill a human

​4)​Class Scyphozoa = the jellyfish or

​**“cup animals”**

​**•  medusa more prominent and**

​    conspicuous that polyp stage

​**•  propel through ocean by jetting**

​    water from GVC

​5)  Class Staurozoa = the star jellies

​**•  used to be included in Class** ​        Scyphozoa

​**•  resembles a medusa but is attached**

​   to substrate by a stalk-like structure

​**•  planula larva creeps rather than**

​   swims or drifts \n 75. What are the characteristics of the ctenophorans?

Phylum Ctenophora:  The Comb Jellies

​**•  live in open ocean**

​**•  have 8 rows of comblike plates of**

​   fused cilia along with two long

​   retractable tentacles used for prey

​   capture

​**•  colloblasts are cells that release a**

​   strong adhesive used in capturing

​   prey (colloblasts are on tentacles)

​**•  ctenophores are largest animals to**

​   use cilia for locomotion

​**•  many are bioluminescent**

​**•  may be triploblastic and have partial**

​   bilateral symmetry \n 76. Describe the features of the phylum Platyhelminthes. What type of gut do they have? How do they manage excretion and osmoregulation? What type of nervous system do they have? How do they \n reproduce?

Phylum Platyhelminthes:  The Flatworms

​  General characteristics –

​1)  ​flattened and solid body (aside

​from incomplete digestive cavity)

​2)  ​free-living flatworms live in marine,

​freshwater, and moist terrestrial

​habitats; scavengers or carnivores;

​move with ciliated epithelial cells

​and also well-developed muscles

​3)  ​parasitic flatworms live inside

​bodies of other animals; range in

​size from 1 mm to many meters

Digestion in flatworms

​**•  incomplete gut that is branched;**

​   functions in both digestion and ​   distribution of food

Excretion and Osmoregulation

​**•  primary function of excretory system**

​   is water balance

​**•  wastes diffuse into gut and are**

​   expelled through the mouth

​**•  flame cells with “flickering” flagella**

​   move water and excretory ​   substances

Nervous System and Sensory Organs

​**•  anterior cerebral ganglion**

​**•  nerve cords and cross connections**

​    that have ladder-like appearance

​**•  eyespots distinguish light from dark**

Flatworm Reproduction

​**•  most are hermaphroditic**

​**•  cross-fertilization is internal**

​**•  can regenerate missing parts** \n 77. Distinguish among the turbellarians, the trematodes, and the tapeworms. Where do they live? What diseases might they cause? Describe any unique structures they possess.

1. ​Class Turbellaria = free-living flatworms ​such as planarians (part of Clade ​Rhabditophora)

​2)  ​Class Trematoda = flukes

​**•  life cycle most often involves two**

​   or more hosts (intermediate host is

​   often a snail and final host is usually ​   some kind of vertebrate)

​**•  many flukes cause disease in** ​   humans (schistosomiasis is blood ​   fluke); other flukes inhabit the liver

​3)​Class Cestoda = tapeworms (also in ​Clade Rhabditophora)

​**•  no digestive cavity – absorbs**

​   nutrients through outer surface from

​   host’s intestine

​**•  body portions are**

​a) scolex for attachment,

​b) neck, and

​      c) proglottids = repetitive

​    sections that are largely ​          reproductive \n 78.Describe the life cycle of the oriental liver fluke.

\n 79. Describe the distinguishing features of the pseudocoelomates.

The Pseudocoelomates have a body ​cavity ​that lies between tissues derived ​from ​endoderm and tissues derived from ​mesoderm.  Pseudocoelom serves as ​hydrostatic skeleton. \n 80. Describe the structure of a nematode.

Nematode structure

​**•  bilateral, unsegmented worms**

​**•  flexible cuticle is molted as they**

​ ​   grow

​**•  oxygen and carbon dioxide** ​   exchange occurs through cuticle

​**•  have longitudinal muscles, but no**

​   circular muscles so can lengthen or

​   shorten but can’t change diameter \n 81. What are some nematode-caused human diseases?

Nematode-caused human diseases

​**•  Genus** Necator found in southern

​   states causes anemia

​**•  Genus** Trichinella causes trichinosis;

​   mature worms form highly resistant

​   calcified cysts in muscle tissue;

​   (don’t eat undercooked or raw pork

​   or bear meat)

​**•**  Enterobius vermicularis = pinworms;

​   infect 30% of children and 16% ​   adults in U.S.; adult pinworms live in ​   human rectum and cause much ​   itching

​**•**  Ascaris lumbricoides infects 1 in 6 ​   people worldwide, but is less ​   common in areas with modern ​   plumbing.  Lives in human intestine.

​**•**  Wuchereria bancrofti = filarial worms

​   that cause elephantiasis; mainly ​   seen in tropical areas; transmitted ​   by an intermediate bloodsucking ​   host such as a mosquito \n 82. Describe the structure of a rotifer. How do they gather food?

Former Phylum Rotifera = the rotifers

​**•  now in Phylum Syndermata along with** ​   the acanthocephalans

​**•  commonly called “wheel animals” for**

​   the corona (ring of cilia) at anterior end

​**•  bilateral symmetry and unsegmented**

​**•  classified as spiralian Platyzoa**

​**•  complex internal organs (Fig 33.12)**

​**•  adhesive toes help to cling to surfaces**

​**•  most live in freshwater and survive 1-2** ​    ​   weeks

​**•  corona used for locomotion and food**

​   gathering; food is crushed by complex

​   jaw in pharynx

​**•  some species reproduce asexually via** ​  ​   parthenogenesis \n 83. What are the defining features of the phylum Mollusca?

Phylum Mollusca:  The Mollusks

​**•  93,000+ describes species (second**

​    only to the arthropods)

​**•  occupy every habitat on Earth**

​**• includes snails, slugs, clams, scallops,**

​   octopus, cuttlefish, oysters, mussels,

​   squid, chambered nautilus, etc.

  ​Mollusks are extremely diverse and

​important to humans.

​**•  size ranges from a few millimeters to**

​   that of the giant squid which can grow

​   to 15 meters long and 250 kg

​**•  mollusks evolved in the ocean; some**

​   slugs and snails are adapted to life on

​   land or in freshwater

​**•  economic importance includes: food,**

​   mother-of-pearl for jewelry

​**•  mollusks can do damage to boats,** ​  ​   ​   docks, pilings, and wood exposed to the ​   sea; zebra mussels are invading ​   ​  ​   freshwater ecosystems

​**•  some slugs and snails damage flowers,**

​   vegetables, and other crops

​**•  some snails are intermediate hosts to**

​   larval stages of parasites such as flukes \n 84. Describe the features of the following groups of mollusks: chitons, gastropods, bivalves, cephalopods.

Class Polyplacophora:  Chitons

​  •  marine only

​  •  8 overlapping dorsal plates

​  •  body is not segmented

​  •  most are grazing herbivores living

​     in shallow marine habitats

​°​Class Gastropoda:  Snails and Slugs

​  •  primarily marine (40,000 species)

​  •  there are freshwater species also

​  •  the only terrestrial mollusks are

​     gastropods

​a)  most gastropods have single shell,

​but some have lost their shell

​b)  most gastropods creep on their

​foot, but in some, the foot is

​modified for swimming

​c)  head has pair of tentacles used for

​​chemo- or mechanoreception; eyes

​are located at base of tentacles;

​some have second set of tentacles

​with eyes on end of tentacles

​d)  unique feature of gastropods is

​**torsion – twisting of body during**

​larval growth so mantle cavity and

​anus are moved to front of body

​e)  gastropods are predators

​f)  mantle cavity serves as a lung in

​    terrestrial gastropods

​°  Class Bivalvia: Clams, Mussels, Cockles

​**•  most of 10,000 species are marine**

​**•  some are freshwater species**

​a)  no radula; no head

​b)  wedge-shaped foot for digging

​c)  have two shells (valves)

​d)  inhalant or incurrent siphon is where ​     water enters bringing food and ​     oxygen

​e)  exhalant or excurrent siphon is ​     where water exits

​f)  see additional anatomy on p. 701,

​​    Fig. 33.19

​°  Class Cephalopoda:  Octopuses, ​Squids, Nautiluses

​**•  more than 600 species**

​**•  marine only**

​**•  very active predators**

​a)  only mollusks with closed ​circulatory system

​b)  foot evolved into arms with suction

​​cups, adhesive devices, and hooks

​for capturing prey

​c)  strong beak-like jaws; radula;

​salivary glands

​d)  largest relative brain size among

​invertebrates

​e)  highly developed nervous system

​f)  complex behavior patterns and

​highly intelligent

​g)  cephalopod eyes similar to ​vertebrate eyes, but evolved ​separately

​h)  no external shell, except for

​chambered nautiluses; cuttlefish

​and squids have internal shell;

​octopuses have no shell

​i)  move by jet propulsion when water

​    that entered mantle is forced out

​    through siphon

​j)  ink sac – used as defense

​k)  chromatophores in skin allow

​     cephalopod to change colors for

​     camouflage or communication

​l)  cephalopods have direct ​    development; that is, no larval stage

\n 85. Define or describe: radula, ctenidia, visceral mass, nephridium, trochophore, veliger.

radula = rasplike structure with rows

​   of chitinous teeth used to scrape ​   food off surfaces

ctenidia = gills (in aquatic mollusks)

​   have much surface area for gas ​   exchange; gills of bivalves also

​   filter out food

visceral mass contains digestive, ​   excretory, and reproductive organs

nephridium = removes nitrogenous ​   ​   waste; works somewhat like a kidney

trochophore larva is free-swimming

​veliger larva is 2nd free-swimming ​  stage \n 86. Briefly describe the nemerteans. \n Phylum Nemertea:  Ribbon Worms

​**•  cylindrical to flattened and very long**

​**•  most are marine; a few are freshwater**

​   or live in humid terrestrial habitats

​**•  most range from 10 to 20 cm in length**

​**•**  Lineus longissimus reported to reach

​   60 meters in length

​a)  nemertean body plan resembles that of

​a flatworm

​b)  some cephalization with two lateral

​nerve cords

​c)  complete gut with both mouth and ​anus

​d)  rhynchocoel = fluid-filled sac that ​​serves as hydraulic power source for ​      proboscis

​e)  gonochoric

​f)   sexual reproduction; but some can ​reproduce asexually by fragmentation

​but many fragments die and don’t form

​a new animal

87. Explain how circular and longitudinal muscles in a segmented body facilitate movement.

Annelids move by contracting circular

​   and longitudinal muscles against the ​  ​  hydrostatic skeleton

​°  Chaetae (setae) = bristles that help

​   anchor annelid in substrate so they

​   don’t slip when they move \n 88. Distinguish between class Polychaeta and class Clitellata (oligochaetes and hirudineans).

Class Polychaeta:  Polychaetes

​**•  marine worms**

​**•  parapodia = fleshy, paddle-like lateral**

​    projections used for swimming,

​    burrowing, or crawling

​**•  parapodia also have important role in**

​     gas exchange; in some species, they

​     are modified into gill-like structures

​**•  predatory polychaetes have powerful**

​jaws

​**•  sedentary tube worms have feathery**

​tentacles for filter feeding as well as

​gas exchange

​**•  most polychaetes are gonochoric and**

​fertilization is external

​**•  Palolo worms – gamete-filled terminal**

​parts considered a delicacy by some

​South Pacific natives

​**•  fertilization** → spiral cleavage → ciliated mobile trochophore larvae → growth to adult

Clade Sedentaria:  Earthworms and ​   Leeches

​**(Note:  The earthworms were formerly**

​in Class Oligochaeta and leeches were

​formerly in Class Hirudinea)

​°​Both groups have a clitellum – a ​thickened band on body that secretes ​mucus to hold worms together during ​copulation and to form a cocoon for ​fertilized eggs to develop.

​°  Earthworm characteristics

​**•  head is not well-developed**

​**• no parapodia**

​**•  few chaetae & project directly from**

​body wall

​**•  eat their way through soil**

​**•  no eyes, but do have light-, chemo-,**

​    and touch-sensitive cells

​**•  hermaphroditic**

​**•  cross-fertilization**

​**•  eggs develop into young worms**

​​    similar to adults

​°  Leech characteristics

​**•  most are freshwater; few are marine;**

​    some live in tropical terrestrial areas

​**•  dorsoventrally flattened**

​**•  hermaphroditic**

​**•  cross-fertilization**

​**•  clitellum only develops during** ​   mating season

​**•  suckers at both ends of body**

​**•  coelom reduced and not segmented**

​**•  no chaetae (except for one species)**

​**•  eat detritus or devour small animals**

​**•  some suck blood – secrete** ​    anesthetics and hirudin ​    (anticoagulant)

​**•**  Hirudo medicinalis= medicinal leech \n 89. What kind of circulatory system do annelids have?

closed circulatory system \n 90. What is the function of the clitellum?

clitellum – a ​thickened band on body that secretes ​mucus to hold worms together during ​copulation and to form a cocoon for ​fertilized eggs to develop. \n 91. How do leeches feed?

eat detritus or devour small animals

​**•  some suck blood – secrete** ​    anesthetics and hirudin ​    (anticoagulant) \n 92. Describe the lophophore and its function.

U-shaped ridge around mouth bearing ciliated tentacles used for gas exchange and guiding food to the mouth \n 93. Distinguish between bryozoans and brachiopods.

Byrozoans:

very small

moss animals

both marine and freshwater

U-shaped digestive system with anus outside the ring of lophophore

zooid secretes a zoecium

zoecia may be specialized for feeding, reproduction, or defense

Brachiopods:

deuterostomes

attach to rocks by pedicel or one shell cemented to rock

lophophore located between shells

U-shaped gut in some; others have no anus \n 94. What are the key features of the arthropods? \n Arthropoda: the most successful of all animals

2/3 all animals

great economic importance

• pollinate crops
• food
• damage crops
• carriers or spreaders of disease

95. List the four extant classes of arthropods and a characteristic that distinguishes them from one another. \n Class Chelicerata (spiders, mites, ticks, horseshoe crabs); two tagmata; chelicerae; pedipalps; walking legs; most carnivores (mites herbivores)

Class Crustacea (crabs, shrimp, lobsters, barnacles, pill bugs); marine; three tagmata; two pairs of antennae; three pairs of appendages

appendages are biramous; feathery gills in large crustaceans; smaller crustaceans occurs directly through body

Class Hexapoda (insects); largest group of animals in terms of number of species and number of individuals; found in every habitat (few in marine)

Class Myriapoda (centipedes and millipedes); both have head and body segments; gonochoric; internal fertilization; lay eggs

Class trilobita (trilobites); extinct

96. What are the advantages and the disadvantages of having an exoskeleton? \n strong and flexible (made of chitin and protein)

antagonism for muscles

support for body

protection against physicals forces

97. What is tagmatization? Name the three tagmata of class Hexopoda. What is a cephalothorax? Which organisms have one? \n Tagmatization: fusion of segments into specialized functional groups

Hexapoda have 3 tagmatas; head thorax and abdomen

crustaceans have a cephalothorax (fuse head and thorax

98. What proportion of all named species are arthropods? \n 2/3

99. Of what substance is the exoskeleton of all arthropods made? \n made of chitin and protein

100. Define or describe the following terms related to arthropods: mandibles, chelicerae, simple eyes, compound eyes, ommatidium, spiracles, book lungs, Malpighian tubules, opisthosoma, pedipalps, spinnerets. \n mandibles: biting jaws (in hexapods, crustaceans, and myriapods)

chelicerae: pincers (in chelicerates)

simple eyes: Ocelli (some hexapods, vertebrates, arthropods, and cephalopods)

compound eyes: ommatidia (hexapods and arthropods)

ommatidium: individual visual units

Spiracles: openings in exoskeleton where air enters; can be closed to prevent water loss (hexapods and arthropods)

book lungs: found in many spiders

Malpighian tubules: slender projections from digestive tract, attached at junction of midgut and hindgut, contain fluid and nitrogenous wastes, water and salts are reabsorbed by hindgut KEY ADAPTATION: life on land (terrestrial insects, myriapods, and chelicerates)

101. What is ecdysis? \n when animals molt their cuticles (they shed and regrow their covering when it becomes too small)

102. Briefly describe the appendages, circulatory system, nervous system, respiratory system, and excretory system of a typical arthropod. \n appendages: jointed; modified into antennae mouthparts or legs; bend to extend or retract

circulatory system: open; heart pumps blood anteriorly; blood is collected through posterior region of one-way valves of the heart

nervous system: double chain of segmented ganglia along ventral surface; three fused ganglia form brain; bodily functions can still be performed if brain is removed; compound and/or simple eyes

respiratory system: Gills (marine crustacean), book gills (horseshoe crabs), outer epithelium or gut for gas exchange (some tiny arthropods), tracheae (terrestrial arthropods), spiracles, and book lungs (in many spiders)

Excretory system: in aquatic arthropods, waste diffuses from blood into gills, Malpighian tubules (in terrestrial insects, myriapods, and chelicerates)

103. What organisms have a nauplius larva? \n crustaceans

104. What two subclasses are included in class Myriapoda? What are the distinctions between the two? \n centipedes and millipedes

centipedes:

• one pair of legs per segment
• carnivores
• poison fangs
• some hatch with a final number of legs others add legs after hatching; (final number of legs when hatching usually care for their young)

millipedes:

• two pairs of legs per segment
• herbivores
• glands produce foul-smelling fluid
• produce cyanide gas
• roll into coil or sphere for defense

105. What is pentaradial symmetry? \n symmetry with 5 different lines to have bilateral symmetry

5 identical parts

106. Describe the five extant classes of echinoderms. \n Class Asteroidea: Sea stars

• organized in parts of five or multiples of five
• predators

Class Ophiuroidea: Brittle stars

• arms are slender and “snake-like”
• arms join central disk very abruptly
• tube feet for feeding, not locomotion
• brittle starts have no anus

Class Echinoidea: Sea urchins and Sand dollars

• no arms
• five double rows of tube feet extend through calcareous test (shell)
• spines are moveable and have a ball-and-socket joint

Class Holothuroidea: Sea cucumbers

• oriented horizontally to substrate
• parts of five
• filter feeders
• have respiratory trees
• if skin is rubbed, can go from rigid to liquid in a couple minutes

Class Crinoidea: Sea lilies and Feather stars

• oral surface faces up, filter feeders

107. What is a water vascular system? What is a madreporite? \n radially organized

extends out to each arm of a sea star

ampulla (bulb) allows tube foot to extend or contract

gas exchange occurs across body surface and the tube feet

holothuroidians also have respiratory trees that branch off the hindgut

water enters and exits through anus

Madreporite: structure on aboral surface where water enters

108. What type of symmetry is found in echinoderm larvae? \n bilateral symmetry

109. What kind of “skeleton” do echinoderms have? What are ossicles? \n endoskeleton

ossicles: calcium carbonate plates that make up endoskeleton

110. How do echinoderms regenerate and reproduce? What is autotomization? \n Many echinoderms can regenerate body parts

• asteroids and ophiuroids autotomize arms
• holothuroidians can eviscerate their digestive system

some echinoderms reproduce asexually by splitting

sexual reproduction is the norm

echinoderms are gonochoric

fertilization is external

111. What are the four features that characterize the chordates? \n Chordates: deuterostomes that include fish, amphibians, reptiles, birds, and mammals

• dorsal, hollow nerve cord (differentiates into brain and spinal cord)
• notochord (becomes the vertebral column)
• pharyngeal gill slits or pharyngeal pouches (used for gas exchange in non-tetrapods; become parts of ear and other head and neck structures in tetrapods)
• postanal tail

112. Describe the characteristics of a tunicate (phylum Chordata, subphylum Urochordata). Compare the structures present in the larval form with those present in the adult form.

Urochordata: tunicates and salps

• marine animals
• immobile as adults
• only larva stage have notochord and nerve cord
• adults have cilia lined pharynx that brings in water where small food particles are then trapped in a sheet of mucus (mucus secreted from endostyle)
• adult tunicates may be colonial
• tadpole-like larvae do not feed and are free swimming for only a few days before attaching to substrate by means of a sucker
• tunic surrounds and supports animal
• one group of tunicates retain their tail and notochord into adulthood; possibly, vertebrate’s evolved from a larva form that became able to reproduce

tunic: tough sac of mostly cellulose

113. Describe the lancelets (subphylum Cephalochordata). \n subphylum Cephalochordata:

• lancelets look like a two-edged surgical knife
• former genus is Amphioxus, but know known as genus Branchiostoma
• notochord retained throughout life
• spend most time partly buried in sand with anterior end exposed
• can swim, but don’t very often
• more pharyngeal gill slits than fishes
• filter-feeders

114. What sets the vertebrates apart from the other chordates? \n Subphylum Vertebrates: chordates with a spinal column

vertebrates differ from tunicates and lancelets in two important respects:

• vertebral column
• distinct and well-differentiated head (craniates)

Other important differences include:

• neural crest
• internal organs (liver, kidneys, endocrine glands, heart and closed circulatory system, excretory system)
• endoskeleton (bone has advantage over chitin because bone is living tissue that is strong without being brittle)

115. How do cartilage and bone contribute to increased size in vertebrates? \n

116. Where did the first vertebrates evolve? \n evolved in the ocean about 545 million years ago

117. What are the five key characteristics of fishes?

• vertebral column: body or cartilaginous spine surrounding dorsal nerve cord and bony or cartilaginous skill encasing brain (exceptions are jawless hagfish and lampreys)
• Jaws and paired appendages (exceptions are lampreys and hagfish) most fish have a pair of pectoral fins and pair of pelvic fins; fins are jointed in lobe-finned fish
• internal gills for extracting dissolved oxygen from water
• single-loop blood circulation: pathway is from hear → gills → body tissues → back to heart; heart is 2-chambered
• nutritional deficiencies: fishes must obtain the amino acids phenylalanine, tryptophan, and tyrosine from their diet as they cannot synthesize these on their own

118. How did evolution of the jaw change the feeding habits of fish? \n Jawless; only had mouth positioned anteriorly that could open to take in food

jaws and teeth evolved and allowed fish to open mouth wider and become more aggressive predators

119. From what structures did fish teeth evolve? \n Teeth evolved from modified scales on skin that lined the mouth

120. What is the function of the lateral line system in fish? \n Lateral line system in fish:

• series of sensory organs projecting into a canal that runs the length of fishes body
• open to exterior through series of sunken pits
• fish’s equivalent of hearing

121. How is reproduction in cartilaginous fish different from that of most other fishes?

• sharks have internal fertilization
• shark pups are born alive
• long gestation period and relatively few offspring has lead to population decline as sharks have been captured in greater numbers (Asian and other like shark fin soup)

122. What is the function of a swim bladder? Which fish have them? \n Swim bladder: outpocketing of pharynx; can ve filled with gas or drained of gas to control buoyancy in water

123. What is the function of an operculum? \n Gill cover: operculum; flexing operculum pumps water over gills; works like a bellows; fish can remain stationary

124. How do ray-finned fish differ from lobe-finned fish? What is the significance of the lobe-finned fish? \n Ray-finned: parallel bony rays support fin; no muscles within fin

Lobe-finned: fins are fleshy and muscular; supported by bone with articulated joints; muscles within fins can move fins independently of one another (no ray-finned fish can do this)

8 species of lobe-finned fish exist today (coelacanths and lungfish)

amphibians evolved from lobe-finned fishes

125. What are the five distinguishing features of living amphibians?

• Legs; frogs and salamanders have four legs; caecilians have lost their legs
• lungs
• cutaneous respiration: a lot of surface area of moist skin allows for diffusion of oxygen through skin which must be kept moist; supplements use of lungs
• pulmonary veins: return aerated blood to heart for repumping
• partially divided heart: imperfect separation of pulmonary and systemic blood circulation; only one ventricle in heart where oxygenated and deoxygenated blood mix

126. The amphibians are thought to have evolved from what organisms? \n lobe-fishes

127. Explain the challenges of moving from an aquatic to a terrestrial environment?

• amphibian ancestors had rather large bodies and it may have been difficult to support weight of body on land. legs helped to support animals on land.
• Gills need water to support them. In air, they stick together. Lungs are a better option for living on land.
• Modifications to heart and circulatory system allowed for more efficient delivery of oxygen to muscles
• reproduction still takes place in water so eggs don't dry out
• amphibians stay near water so body doesn’t dry out

128. What are the distinguishing features of order Anura (frogs and toads), order Caudata (salamanders and newts), and order Apoda (caecilians)? \n Order Anura (“without a tail”): frogs and toads

• live in deserts, mountains, ponds
• both return to water to reproduce
• frogs
  • moist sin broad body, long hind legs
  • live in or near water
  • tadpole → Adult frog

129. What are the three key characteristics of the reptiles? \n ​1)  Amniotic eggs = watertight eggs that

​ ​contain a food source (yolk) and a

​series of four membranes. (All modern

​reptiles, birds, and mammals show

​this pattern of membranes in the ​eggs.)

​a)  chorion = outermost membrane

​lies just beneath the porous shell;

​allows exchange of respiratory ​gases, but retains water

​b)  amnion = encases developing

​embryo within fluid-filled cavity

​c)  yolk sac = provides food from yolk

​via blood vessels connecting to

​embryo’s gut

​d)  allantois = surrounds cavity into

​which waste products from embryo

​are excreted

​2)  Dry skin

​a)  layer of scales covers bodies;

​prevents water loss

​b)  scales contain keratin – the same

​protein that forms claws, ​fingernails, hair, and bird feathers

​3)  Thoracic breathing

​a)  reptiles developed pulmonary breathing; rib cage expands and contracts to suck air into lungs and then force it out

​b)  capacity of this system is limited by the volume of the lungs

130. What is an amniotic egg? Define: chorion, amnion, yolk sac, allantois. \n SEE ABOVE.

131. How is breathing in amphibians different from breathing in reptiles? \n reptiles developed pulmonary breathing; rib cage expands and contracts to suck air into lungs and then force it out

Amphibians have lungs

132. How is the circulatory system of reptiles an improvement over that of fish and amphibians? \n reptiles: mixing of oxygenated and ​deoxygenated blood is lessened by ​extending septum partially through ​ventricle

fish: single-loop blood circulation:  pathway is from heart → gills → body tissues → back to heart; heart is 2-chambered

amphibians have pulmonary veins: return aerated blood to heart for repumping

Partially divided heart: imperfect separation of pulmonary and systemic ​blood circulation; only one ventricle in​ heart where oxygenated and deoxygenated blood mix

133. Define: ectothermic, endothermic. \n (endothermic animals generate their heat internally)

ectothermic = obtain their heat from ​external sources

134. What are the distinguishing features of order Chelonia (turtles and tortoises), order Rhynchocephalia (tuataras), order Squamata (lizards and snakes), and order Crocodylia (crocodiles and alligators)? \n 1)  Order Chelonia: turtles and tortoises

​•  no teeth, but have sharp beak**

​•  only reptiles to have a shell**

​2)  Order Rhynchocephalia: tuataras

​•  only found on small islands off coast of New Zealand

​•  have “third eye” on top of head; eye is covered by thin layer of scales; has lens and retina; connected by nerves to brain; may alert tuatara when it has been exposed to too much sunlight

​3)  Order Squamata: lizards and snakes

​•  lack of limbs, movable eyelids, and external ears in snakes

​•  this order distinguished by paired copulatory organs in the males

​•  head and jaws have strength and mobility

​•  most lizards and snakes are carnivorous

​4)  Order Crocodylia: crocodiles and alligators

​•  all crocodilians are carnivores

​•  crocodiles resemble birds more than they resemble other reptiles

​-- build nests; care for their young

-- have a four-chambered heart

135. In what ways do crocodiles resemble birds more so than they resemble other living reptiles?

build nests; care for their young ​have a four-chambered heart

136. What are the key characteristics of birds? \n 1)  Feathers = modified reptilian scales; made of keratin

​•  Two functions of feathers are:

​    a)  provide lift for flight

​    b)  conserving heat

​2)  Flight Skeleton

​•  bones are thin and hollow

​•  many bones are fused and makes bird skeleton more rigid than reptilian skeleton

​•  no other living vertebrates have fused collarbone or keeled breastbone

137. What is Archaeopteryx? \n Archaeopteryx = fossil of first known bird

​•  fossil found in Bavaria in 1862

​•  had skull with teeth; very few fused bones; bones were probably solid and not hollow; had long reptilian tail; no enlarged breastbone; had feathers on wings and tail

138. What modifications or adaptations to the respiratory and circulatory systems have allowed birds to cope with the heavy demands of flight? What is endothermy and how is it important?

superefficient lungs that permit sustained, powered flight

endothermy = warm-blooded

​•  feathers help to conserve body heat

​•  higher temps permit metabolism of birds flight muscles to proceed at rapid pace

139. What are the distinguishing features of the mammals? \n 1)  Hair – all mammals have hair (whales and dolphins have sensitive bristles on their snouts)

​•  fur and endothermy allowed mammals to move into colder ​climates

​•  hair can also serve as camouflage

​•  hairs can function as sensory structures

​•  hairs can serve as defensive weapon

​2)  Mammary glands

​•  found in all female mammals

•  secrete milk (high-calorie food to support rapid growth of newborn​   mammals

​3)  Endothermy = warm-blooded

​•  mammals can be active any time of day or night

•  endothermy depends on more efficient blood circulation and more efficient respiration

​4)  Placenta

​•  most mammals carry young internally in a uterus and nourishment takes place through the ​   placenta

​•  birth of live young

Other adaptations:

​5)  Specialized teeth – can determine diet of mammals by looking at teeth

​a)  meat eaters have canine teeth and triangular molars and premolars for tearing off pieces of flesh

​b)  herbivores have flat, chisel-like ​incisors for cutting off vegetation ​and flat, ridged molars for grinding ​tough plant tissues

​6)  Digestion of plants

​Most mammals are herbivores and ​cellulose comprises most of a plant’s ​tissues.  Mammals don’t have the ​proper enzymes to break down ​cellulose and must depend on bacteria ​to do the job.

​a)  ruminants (cows, buffalo, deer, etc) have four-chambered stomach that ​acts as fermentation vat; bacteria ​in one of stomach chambers break down the cellulose

​b)  rodents, horses, rabbits, elephants have relatively small stomachs and plant material is digested in the ​large intestine; the bacteria that break down the cellulose are found in the cecum

​7)  Development of hooves and horns

​  •   keratin, the same protein that ​composes hair, is the structural ​building material of claws, ​fingernails, and hooves

​a)  hooves of the foot protect the toes and cushion them from impact

​b)  horns made of a bony core ​surrounded by sheath of keratin; bony core attached to skull; horns are not shed

​c)  antlers are made of bone; male deer grow and shed a set of antlers every year; while growing ​in summer, they are covered by ​thin layer of skin called velvet

​8)  Flying mammals:  Bats

​**•  batwings are modified forelimbs**

​**•  leathery membrane of skin and** ​   muscle stretched over four fingers

140. What types of specialized teeth are found in mammals? \n Specialized teeth – can determine diet of mammals by looking at teeth

​a)  meat eaters have canine teeth and ​triangular molars and premolars for tearing off pieces of flesh

​b)  herbivores have flat, chisel-like ​incisors for cutting off vegetation ​and flat, ridged molars for grinding ​tough plant tissues

141. Define: herbivore, carnivore, omnivore. \n Herbivore: an animal that feeds on plants

carnivore: an animal that feeds on flesh

omnivore: an animal that feeds on both plants and flesh

142. What is the building material for claws, fingernails, hooves? \n Keratin

143. Which mammals are capable of powered flight? \n birds

144. Distinguish among the monotremes, marsupials, and placental mammals. Give examples of each. \n 1)  Monotremes = egg-laying mammals

(duck-billed platypus and echidna)

•  lay shelled eggs

•  have cloaca

2)  Marsupials = pouched mammals

•  different pattern of embryonic development

-- fertilized egg surrounded by chorion and amniotic membranes but no shell forms

-- nourished by yolk in egg

-- short-lived placenta forms before birth

-- within 8 days of fertilization, embryonic marsupial born

-- crawls into pouch and latches onto mammary nipple where it continues developing

3)  Placental mammals

•  placenta nourishes embryo through entire development period in uterus

•  chorion and allantois form placenta

•  young undergo considerable development before they are born

145. What is meant by a “tube within a tube” arrangement? \n nematode body structure; secretes tube that is able to lengthen and shorten but no circular muscles to change diameter or length

146. What is homeostasis? How is it important? \n

147. Compare the nervous systems of: cnidarians, earthworms, arthropods, echinoderms, mollusks, flatworms, and humans or other vertebrates. (See p. 1086) \n Cnidarians: have a nerve net

Earthworms: no eyes, but do have light-, chemo-, and touch-sensitive cells

arthropods: double chain of segmented ganglia along ventral surface

• three fused ganglia form brain \n • functions such as eating, moving, and copulating can be carried out even when brain is removed \n • compound eyes composed of ommatidia (individual visual units) \n • ocelli = simple eyes present in some arthropods

Echinoderms:

148. Compare open and closed circulatory systems. Give examples of organisms that possess an open or a closed circulatory system. \n

149. Compare the hearts of fish, amphibians, reptiles, birds, and mammals. \n

150. Compare the respiratory structures of fish, amphibians, reptiles, birds, and mammals.