BIOL 200 Week 7-9

Supergroups of Animals / Animal-LIke Taxa

Alveolata, Rhizaria, Opistokonta (multicellular), Excavata

Animal Rooted Tree Order

Protists, Basal Phyla, Protostomes, Deuterostomes

What was the paradigm shift in the animal rooted tree?

Multicellularity: gave rise to the basal phyla

How many times did multicellularity occur? In tree of life? In animal phylogeny?

once in animals, many in tree of life

What did multicellularity allow for in animals?

larger size, increased mobility, better access to resources, specialization

What groups are in the Basal Phyla

Porifera (Sponges), Cnidarians, Ctenophora

What are the protostome lineages? What distinguishes them?

Lophotrochozoa and Ecdysozoa. Distinguished by different patterns of development.

Cephalic / Caudal

Head / Tail

Dorsal / Ventral

Dorsal: Back, Ventral: Belly

Proximal / Distal

Proximal: Closer structure, Distal: further structure

Superior / Inferior

Superior: above in respect, Inferior: below in respect

What are the Basic Tissue Types

Epithelial, Connective, Muscle, Nervous

What is included in epithelial tissue?

Skin, linings of digestive tract, blood vessels, etc.

What are the two forms of epithelial tissue?

Simple and Stratified

What types of simple epithelial tissue is there?

Simple squamous: flatenned and tightly bound layer of single cells (lining of blood vessels, endothelium)

Simple Cuboidal

Simple Columnar: digestive tract lining

What types of stratified epithelial tissue are there?

Stratified squamous: flat cells at top with bottom columnar, high in keratin and waterproof

Stratified cuboidal

Pseudostratified columnar: one layer, but with irregular shape and nuclei

Connective tissue, what is it and what is included?

cells embedded in a matrix that functions in supports, binding, transport, or immunity.

Includes loose fibrous connective tissue (dermis, fibroblast, collagen, elastic fibers, matrix), hyaline cartilage, bone, adipose tissue

Muscle Tissue what is it and what is included

Elongated cells with contractile proteins for movement. Includes skeletal (common), cardiac (striated), smooth (non striated)

What are the ten organ systems?

Integumentary, Skeletal, Muscular, Digestive, Circulatory, Respiratory, Nervous, Endocrine, Excretory, Reproductive

Integumentary includes

skin and hair, feathers, scales

Skeletal includes

external and internal hardened parts. Bones, cartilage, hair, feathers, scales, teeth, beak. Can be made of bone, cartilage, chitin, keratin

What are the two muscular components?

Somatic (Striated): support body wall, tail and appendages

Visceral: smooth muscles with gut, striated muscles with branchial/gill arches

Types of blood vessels

Arteries, Veins, Capillaries, Lymphatic

Respiratory system in aquatic vs terrestrial organisms

-gills and lungs evolved separately from digestive tract

-gills came from lateral slits in anterior region of digestive tract

-lungs came from primitive fishes, from foregut outpouching of digestive tract

-modern fishes had lungs become swim bladder, terrestrial animals kept lungs

What are the patterns of organization

Asymmetry (no plane to bisect into mirror images)

Radial Symmetry (infinite planes to bisect)

—> Biradial: two planes two divide (ctenophores/ comb jellies)

—> Pentaradial: 5 planes to bisect (due to arms)

Bilateral Symmetry (one plane called median plane divide into left and right)

What are the patterns of organization

Unicellular, Diploblastic, Triploblastic

Describe Diploblastic Organization

Has two embryonic cell layers: Ectoderm and Endoderm

Endoderm: lining of digestive cavity, digestive tissues

Ectoderm: epidermis and nervous system

Looks like ball of cells: endoderm —> mesoglea (non-cellular) —> ectoderm
Occurs in some basal phyla

Mesoglea

gelatinous, non-cellular, jelly-like substance found between the ectoderm and endoderm in cnidarians (jellyfish, corals) and ctenophores

Describe Triploblastic Organization

Three embryonic cell layers: ectoderm, mesoderm, endoderm

Ectoderm: epidermis, nervous tissue

Mesoderm: bulk of body tissues

Endoderm: gastrodermis, gut lining

Contains body cavity called coelom

In protosomes and deuterostomes

What is the coelom? What patterns can it be

A true coelom is an internal body cavity completely surrounded by mesoderm.

Acoelomate pattern: lacking the fluid filled cavity

Pseudocoelomate pattern: not fully mesodermal lining, could be between mesoderm and endoderm

Coelomate: has mesentary which is a thin membrane that joins digestive tract to walls

What is a protostome and what characterizes it?

One of two main groups of animals (sister to deuterostomes).

Spiral cleavage (specific to lophotrozoans) as development

—> has 3 divisions after fertilization with 2, 4, 8 cells and unaligned layers

—> Blastopore develops into mouth

—> Shizocoelous coelom (not universal)

—> Trochopore larva (have or had in past), only protostomes have

What characterizes deuterostomes

Radial Cleavage: 8 cells arranged into two layers, complementary

Blastopore develops into anus

Enterocoelous coelom

No trochophore larva

What are the three Eras?

Mesozoic, Cenozoic, Paleozoic

What are the four supergroups of animal-like protists

Alveolata, Amoebozoa, Excavata, Rhizaria

Protists are non-monophyletic

Unrooted, don’t know order of evolution

What is the significance of paleozoic time period to animal life?

Around 540 mya, contained the Cambrian explosion of animal phyla (all current groups present at this time)

However, animal like protists well before this

What was the most sever mass extinction?

The Permian

80% and 70% of terrestrial life went extinct.

Due to volcanic event, its atmosphere and climate impact

Describe generally the evolution of protists

They can be traced back 1.5 bya with fossils

All groups were present by Cambrian period

They are polyphyletic

Some species are animal like and plant like (Euglenoids flagella and photosynthesis)

Protozoa group meaning first animal

What are the generalized features of animal like protists

Unicellular, but complex with membrane bound system (nucleus, mito, membrane, lysosomes)

Contain pellicle: proteinaceous zone of cell interior to inside plasma membrane, that provides rigid

Supported by contractile vacuoles: keep internal state in narrow limits by expelling excess water

What are the asexual forms of reproduction in animal-like protists?

Binary fission (divide along long or perpendicular axis)

Schizogony (multiple mitosis of nucleus before cell division - mutlinucleate)

Budding (unequal cell division)

Describe animal-like protists relation to sexual reproduction

Variable among taxa

Haploid individuals produce gametes in zygotic meiosis

Amoebas do not sexually reproduces

Ciliates have complex form with macro and micronucleus

What defines the Excavata Protozoan Group

Named for excavated feeding groove

Some plant like (phytoflagellated) some animal like (zooflagellated) flagella

Important primary producers

Several are pathogenic

Describe the important pathogenic excavata species

Giardia intestinalis: waterborne disease, infecting small intestine

Trichomonas vaginalis: sti where men are asymptomatic

What defines the amoebozoan group

Amoeboid shape that moves with pseudopodia (extensions of cell that body flows into)

Lack pellicle

Phagocytosis for food

Do not sexually reproduce

What are some characteristic amoebozoan species

Naegleria fowleri causes encephalitis

Acanthamoeba causes keratitis

Entamoeba hisolyca results in amoebic dysentery and has no mitochondria

Describe the rhizarians (TSAR Clade)

They are amoeboid, but not sister to amoebozoa

Some have filopodia or axopodia (specialized pseudopodia)

Includes Foraminifera: secrete calcium carbonate, making white cliffs of dover and abundant since Cambrian

Describe the alveolata group

Highly variable with three groups: Dinoflagellates, Ciliates, Apicomplexans

Have or had plastids (phytoflagellates)

have stacked vesicles (alveoli) below plasma membrane

What are dinoflagellates

alveolates

marine

biflagellated

bloom = red tides

Describe ciliates

Alveolates such as paramecium

Cilia for moving and feeding

Cytostome mouth

Freshwater and marine

Free living meaning less disease relations

Fixed by rigid pellicle

Asexual: transverse fission (perpendicular)

Sexual: conjugation with dimorphic macro and micro nuclei

Describe apicomplexans

They are alveolates which are intracellular parasites

Have ring shaped apical complex

No cilia or flagella (internal parasites)

Include: plasmodium, cryptosporidium, toxoplasma

What disease is plasmodium related to, and what does its life history look like?

Related to malaria

Sporogony: asexual spores generated in mosquito who can transmit sporozoites to humans

Schizogony phase: spores in liver undergo Exoerythrocytic cycle where cells divide without division and then rupture into blood cells

Gametogony phase: in blood gametes are produced in the Erythrocytic cycle that mosquito can bite

When mosquito bites, gametes fertilize and meiosis occurs to make spores

What are the common features of Metazoans / Basal Animal Phyla

Multicellular animals

Presence of monoflagellated cells

Mitotic aster apparatus

Cell junctions

Proteins for movement and other functions (protists didn’t have this extent)

Monophyletic

What are the selective advantages of multicellularity

Larger, complexity, resource efficiency, less prone to be eaten, greater motility

How does multicellularity change what it means to be an individual

Multicellular organisms can undergo apoptosis:

—> stripping down of parts

—> supports early embryonic development

—> apoptosis when replication errors to prevent cancer

Multicellular organisms have division of cell types and functions:

—> reproduction in gametic cells

—> somatic cells seem to be against evolution, but are just a greater part of multicellular organisms (shifting of roles)

Porifera - Pore bearer refers to what species

Sponges

What are the for important cell types of Porifera

Pinacocytes: flattened pavement of integument

Porocytes: are the characteristic cells of poriferans, connect outside water to inside

Choanocytes: embedded in body wall and extending into cavity

Mesenchyme: unspecialized cells

What supporting structures are in Porifera

Spicules, which provide evidence for skeletal system

Made of various materials dependent on species

Needle like are glass like silicon, while varied structures are proteinaceous

hard = skeletal elements

has no tissues or organs

How do the choanocytes function in Porifera

the collar contains a flagella which moves with water current

water drawn in through pores with negative pressure

passing water contains particulates that get stuck on collar and move into cell and vacuole

water leaves through osculum of sponge

Describe the basic body form of Poriferans

Have little cellular specialization

Contains interior spongocoel which is the primary cavity

Pinacocytes line exterior, with porocytes embedded and open into cavity

Choanocytes in body wall stick out into spongoecoel

Water is constantly filtered through

What ecological roles do Porifera serve

Water filtration for clear water in coral reefs

Food for reef fishes

Describe the variation of sponge body forms

Walls can fold to increase chambers

Ascon, Sycon, Leucon with increasing folding

Leucon loses spongocoel

Describe reproduction of sponges

Asexual reproduction:

—> common in freshwater

—> gemmule structures allow for overwintering (released before winter and contain amoeba until released in spring)

Sexual reproduction:

—> monoecious and asynchronous

—> choanocytes produce gametes

—> planktonic larva: in water column briefly before settling

Outline the diversity of sponges

~9000 spp

four groups differentiated by spicule characteristics

wall complexity not phylogenetically informative

What species are part of the Cnidara phylum?

Hydra, jellyfish, anemone, coral

What are shared characteristics of cnidaria

Radial or biradial symmetry

Diploblastic tissue organization

Gastrovascular cavity

Nerve net

Cnidocyte cells

Describe the Diploblastic development of Cnidaria

Ectoderm gives rise to epidermis with:

-epitheliomuscular cells that can contract (most)

-cnidocytes

Endoderm gives rise to gastrodermis (ciliated and moves water)

Describe the Life Cycle of Cnidarians

Alternation of Generation between polyp and medusa stages

Polyp: sedentary, structural body column with large cavity and mouth at apical part, asexual budding into medusa

Medusa: free swimming, flipped and shortened column to polyp (bell shape), mouth downward with tentacles, sexual (dioecious) with gametes released into water

Zygote developes into ciliated larva called planula

Describe the structure and function of Cnidocytes

Functions: capturing prey, defense, motility, competition

Structure:

nematocyst is inner stinging part, inverts to produce tube and string

operculum plate covers inner,

cnidocil is trigger

may have barbs, be sticky, or other methods of function

Describe the hydrostatic skeleton present in Cnidarians

pressure on walls make turgid structure that muscles counterract

provides support, functions in movement

not hard like bone, cavity can be filled with water,

outline the diversity of Cnidaria

Hydrozoans: small, common, marine, colonial polyps (some feeding, some reproductive)

Scyphozoa: marine, true jellyfish, medusa dominant, dioecious

Cubozoa: box jellyfish, toxic (predation or defense), tentacles in four corners

Anthozoa: marine, polyp only, gastrovascular cavity divided by mesenteries (with gonads, cnidocytes), symbiotic with zooxanthellae, external radial symmetry, internal biradial, include anemones

Describe the characteristics of Ctenophora or Comb Jellies

diploblastic (have muscles so maybe triplo)

biradial

mesoglia is cellular with muscle cells

gastrovascular cavity with anal opening

nerve net

monoecious with external fertilization

Describe the structure of a Ctenophore / Comb Jelly

Has eight comb rows along body walls with cilia

Colloblast cells on tentacles are sticky to catch prey

Paired tentacles = biradial

What are the characteristic features of Lophotrochozoa

Trochophore Larva: characteristic shape, cilia at apex and anus, complete digestive system (two orifice, anterior/posterior with tube)

Lophophore: feeding organ, trunk with ring at top, with ciliated tentacles, mouth at top of column that loops back up to anus

If either is present = lophotrochozoans, neither doesn’t mean either way

Is there are characteristic feature of the Phylum Platyhelminthes? Describe common characteristics of Platyhelminthes

Platyhelminthes or Flatworms have no universal features and are not monophyletic

Common features:

worm with flat body

acoelomate; instead filled with mesodermal parenchyma

bilateral symmetry; some cephalization (anterior)

organ system level organization (first group), cnidarians only had hints of netlike nerves and skeletal elements

incomplete gut

protonephridia excretion

nervous system: anterior ganglia, longitudinal ventral nerve cords

monoecious

What groups or classes are within Platyhelminthes

Turbellaria (planarians)

Trematoda (flukes)

Monogenea (monogenetic flukes, ectoparasites)

Cestoidea (tape worms)

Describe characteristic features of Turbellaria / Planarians

Polyphyletic

Free-living flatworms: benthic, marine, freshwater, few terrestrial

Mobile: circular and longitudinal muscle fibers, cilia on ventral surface

Predatory

Dorsal/ventral flattening —> compressed body form

Describe anatomy of Turbellaria / planarians

digestive system: single opening with protruding pharynx, three lobes (anterior two posterior), diverticula pouches extend laterally

thin epidermis

circular muscles: extend to become thinner

longitudinal muscles: shorten length

parenchymal tissue unspecialized

parenchymal muscle support thinner

ventral nerve cords

Describe gut morphology of Turbellaria

variable from tube to complex branching

branching of diverticula increases cell coverage, which provides alternative to blood vessels

Describe excretion of Turbellaria

Through protonephridia unit

Long tubules around periphery, flame cell at cap, cilia of flame cell push down fluid which is filtered for nutrients and excreted

Describe nervous system of turbellaria

pair of ventral nerve cords

some have netlike nerves extending into peripher, which coalesce into ganglia // others branch with segmental patterns where commissures connect nerve cords

consists of sensory and motor neurons

Describe reproduction in Turbellaria

most complex system in planarians

monoecious

copulatory sac receives sperm: stored and sent into oviducts

eggs deposited outside in cocoon

vitellaria in eggs for nutrients

mostly non larval development

also asexual: transverse fission

What are trematodes

Trematodes are parasitic flukes, usually associated with the bile duct of digestive system and target vertebrates

They are flattened and wide like a whales tail

Most diverse of platyhelminthes, two subclasses Digenea (two host) and Aspidogastrea (one host)

Complex life-histories

Describe trematode internal anatomy

simple except reproductive system, dispense most of anatomy

host provides living setting

almost exclusively sexual

eggs into host digestive tract

digestive structure: mouth and two long ceca tubes

What is the tegument of trematodes and its structure?

the outer covering or skin that serves as defense

it is syncytial: a multinucleated structure due to cell fission

Outer tegument: glycocalyx: maintains contact with bile duct and extends cytoplasmic bodies below basement membrane

Inner tegument: basement membrane (thin sheet support)

Describe a life history of a common Liver Fluke

Produces fertilized eggs in host

Eggs in water develop into larva

Cilia of larva find host (snail), form sporocyst and redia that produce hundreds of embryonic cells

Cercaria larva are motile, enter water to find second intermediate host (Plant)

Consumption of plants repeats process

What are monogenea

include parasites of fish which burrow into skin or gills of animals

What are cestoidea

Tapeworms (highly specialized gut parasites)L

-target vertebraes and intestines

-simple anatomy: secondary evolution trend as ancestors more complicated

-intermediate hosts, usually one

Describe the structures of Cestoidea

Anteior: Scolex (attaches to inner lining of digestive track with hooks)

Neck narrows

Posterior: divided proglottid (maturation away from neck) is a reproductive structure, can reproduce with other tapeworms

Gravid ploglottid: matured, sac of fertilized eggs, voided through host feces until next host

beef Tapeworm: No digestive system; rudimentary nervous and excretory system

“male and female reproductive system on wheels”

Describe the lifecycle of a Beef Tapeworm

Using scolex to attach to intestine, tapeworm sexually reproduces

proglottid breaks off and is eliminated

cow ingests eggs which hatch in oncosphere (thorned and burrows into through digestive tract to circulatory system)

Embeds in muscle and becomes inactive cyst

Human eats beef with cyst —> activates

Describe generalized traits of mollusks (and what they include)

Soft bodies

includes snails, bivalves, octopus, squids, etc.

triploblastic, coelomate

morphologically variable, united with:

Body form: muscular head-foot (ventral), visceral mass (dorsal),

Mantle (inside shell) and mantle cavity

Radula (chitinous): rasping for mouth

Trochophore larva (many)

Open circulatory system (except cephalopods): blood not in vessels, direct cell contact

What are the three important classes of Molluscs

Gastropods, Bivalves, Cephalopods

Describe the generalized anatomy of Molluscs

Ventral muscular head-foot with overlying visceral mass

Cephalization, with head like structure at anterior

Skeletal shell element

Mantle iand mantle cavity

Outline the structure of the shell/mantle/mantle cavity, with Ex: Bivalve

Top Shell: periostracum (protein outer layer), prismatic layer (mineralized), nacreous layer (smooth inside, protein, CaCO3)

Mantle: lined by epithelium, thick at shell tip (shell gland), lay down materials (grow shell),

—> pearl forms between nacreous layer and epithelium when irritant gets trapped

Mantle cavity: between mantle and head foot, water can circulate, contract walls for ventilation of water or air,

—> may contain gills

—> release nitrogenous (nephridium) and digestive (anus) wastes from anus into cavity

—> releasing reproductive products

Describe the radula structure of molluscs and function

Radula is within diverticula of radula sac

It can protrude, wrapping around cartilage

scraping algae or biofilms

associated with mouth, but not homologous to teeth

What species are gastropods

Snail, slugs, limpets

Describe gastropods characteristics

Aquatic (both marine and freshwater) and terrestrial

Intermediate host for parasites

~65,000 spp.

Describe torsion of gastropods

While ancestors only had larvae, modern have torsion twisting

Larval form visceral mass twists 180 counterclockwise

Results in: cavity superior to head, gills above head, anus feeding into area above head

Hypothesized as protecting head which can withdraw into cavity

Describe respiration of gastropods

Aquatic: gill structures in mantle cavity

Land: mantle cavity highly vascularized (like lung)

Open nephrostome / pneumostome allow air or water in

Describe the coiling shell of gastropods

Right or left handed based on species

Assymetrical

Protection, hydration

Constrains space: one nephridium, one atrium, one lung

Describe reproduction in Gastropods

Most lay eggs

Some dioecious, broadcast spawners

Monoecious: copulation and mutual sperm exchange, protandrous or protogynous

Some live bearing (viviparous)

Marine forms have trochophore larvae —→ veliger larvae

Describe three examples of Gastropods

Banff Spring Snail: survive hot temperatures, at risk

Cone Snails: decorated, radula with harpoon and toxins to immobilize and consume fish

Nudibranchs: live in coral reefs