Biology 102 exam 2 Richard Mccain

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Protists

Wide range from microscopic, single celled organisms to enormous multicellular

Used as a sort of junk drawer for organisms that don’t fall into animal, plant, or fungi

Why difficult to classify protists

NOT PLANTS

• Gametes and Zygotes are not protected from drying out

NOT FUNGI

• Do not have chitin in their cell wall

NOT ANIMALS

• Do not go through embryonic development

Protists diversity facts

Could be split into as many as a dozen kingdoms (very diverse)

Protists morphology

Most are unicellular, but not all

many have very high level of structural and functional complexity, even if they are just one cell

General biology of the protists

Life cycle

• most are free living (non symbiotic living)

• some parasitic

• asexual reproduction common

• sexual reproduction when times are tough

• some life cycles simple, some complex

Size

• vary in size from microscopic to hundreds of meters

Ecology of Protista

Great and good and great for enviroment

Photoautotrophic forms

• produce oxygen

• function as producers in both types of water

• major component of plankton

• serve as food for heterotrophic protists and different animals

Many protists symbionts

ex. coral reefs and protists

Transportation of protists

3 main ways

1. Paramecium use hair like apendages called cilia

2. Amoeba uses limb like pseudopodia to anchor itself and then pull itself forward

3. Euglena uses a whip like tail called flagellum

Metabolism of protists

Could be aerobic or anaerobic

protists that get energy through photosynthesis are called photoautotrophs and have chloroplasts

Heterotrophic consume organic materials for nutrition ex. Saprobes eat dead organisms

Mixotrophs obtain nutrition through either way depending on what is available

Phagocytosis

Happens in usually amoebas

use pseudopods to engulf food inside

after it is digested with hydrolytic enzymes within lysosome

the rest that is not wanted is thrown out of the cell.

Reproduction of protists

Many can do both asexual and sexual reproduction which include budding and binary fission for asexual or meiosis and fer

Sexual reproduction in protists

Used in time of stress as they need to better adapt to an environment

Pros

• better genetic diversity

• Better adaptation to changing environment

• more efficient in getting rid of bad genes

• more efficient in getting good genes

• produces spores that can resist environmental stress

Cons

• energy costly

• risk of gene conflicts

• time to locate partner

• breaks well adapted genomic configs

Asexual reproduction in protists

most common way for reproduction

Pros

• good for energy

• no risk of gene conflicts

• preserves well adapted genome configs

Cons

• clones

• low diversity for genes

• less adaptive to changes in environment

• less efficient in getting rid of bad genes

• less efficient in getting good genes

Preferred habitat of Protist

prefer the moist or aquatic environments, this includes:

• freshwater or marine enviro

• damp soil

• snow

• host animals and plants

• dead bodies

Green algae

Chlorophyta

Algae refers to many phyla of protists that photsynthensize

inhabit many enviroments including oceans, freshwater, snowbanks, tree bark, and turtle backs

many are symbionts with fungi, plants, or animals

majority unicellular, but many are filamentous or colonial. some multicellular

plants thought to be from chlorophyta as

1. they have cell wall that has cellulose

2. have chlorophylls a and b

3. store excess food as starch

Red Algae

Rhodophyta

multicellular

live in warmer seawater, some deep as 200m

used in many things

• Agar- capsule, dental impressions, cosmetics

• Carrageen- emulsifying agent

• Porphyra-whats wraps sushi

Brown Algae

Phaeophyta

~1500 species

most in colder ocean water

no unicellular or colonial forms

Morphology

• some small forms with simple filaments

• large multicellular forms that can exceed 200m

Pigments

• Chlorphylls a and c

• Fucoxanthin (carotinoid pigment)

• excess food stored as carbohydrate called laminarin

Yellow-green Algae

Chrysophyta

Diatoms are most numerous unicellular algae in oceans

significant portion of phytoplankton

Cell wall

• two valves, with large valve acting as lid

• contains silica

Diatomaceous earth ised as

• filtering agents

• sound-proofing materials

• polishing abrasives

Endosymbiosis

First eukaryote probs came from prokaryote that went through membrane proliferation, the compartmentalization of cellular function(organelles). Mitochondria from aerobic prokaryote and chlorophyll from photosynthetic one

Primary endosymbiotic event

A heterotrophic eukaryote consumed a cyanobacterium

Secondary endosymbiotic event

The cell that came from primary endosymbiosis is consumed by a second cell

Zooflagellates

Colorless heterotrophs

most symbiotic and many parasties

cause diseases like STI’s, severe diarrhea, or Chagas disease

Amoeboids

Rhizopoda

move and ingest food with pseudopods

make use of phagolysosomes for phagocytosis

Ex. entamoeba histolytica

Ciliates

Ciliophora are them most complex of the protozoans

hundreds of cilia beat in rhythmn

most holozoic, eat food whole

divide by transverse binary fission during asexual

two nuclei

1. micronucleus- heredity

2. macronucleus- metabolism

Dinoflagellates

exhibit great variety in shape

many encased in cellulose armor and then have two flagella that are within grooves of the “armor”

these flagella cause a spinning motion

bioluminescence is sometimes seen in dinoflagellates

Plasmodial Slime molds

Myxomycota feed like fungi and make spores but no cell wall and have flagellated cells

• body in form of plasmodium

• diploid, multinucleated, cytoplasmic mass

• enveloped in slimy sheath

• produces sporangium which produces spores

Cellular Slime Mold

Acrasiomycota feed like fungi and make spores but no cell wall and have flagellated cells

• body in the form of indiviudal amoeboid cells

• later aggregate into pseudoplasmodium which makes sporangium and spores

Protists are main producers

feed most of the worlds aquatic species directly or indirectly

one half of worlds photosynthesis by various protists

Symbionts protists

can provide nutrition to other organisms through photosynthesis. Ex. coral and protists

Decomposer protists

Saprobes specialize in absorbing nutrients from nonliving organic matter

have the essential function of returning inorganic nutrients to soil and water

part of process of life

Parasitic protists

significant portion are pathogenic parasites that must infect other organisms to survive and propagate

include malaria, and other things in humans

some prey on plants and cause crop destruction

basics of fungi

Mushrooms: the fruiting body of a fungus, containing spores that act similarly to seeds in plants

Hyphae: long thin strands that tangle together to make up mycelium

Mycelium: the main structure of a fungus

Mycorrhiza: in the mycorrhizal fungi, the place where the hyphae attach to plant roots

Habitats of fungi

Fungi prefer moist environments but realllu are everywhere

most members can be found in the forest

Characteristics of fungi

~80,000 species

• mostly multicellular eukaryotes that share a way of nutrition

• heterotrophs cells release digestive enzymes and then absorb nutrients

• most are saprobes

• some parasitic

• some mutualistic

• biggest organism to scale on earth

Fungal Decomposers

fungi are important of ecosystem

release element from decaying matter, making them available to other living organisms

ex. bracket fungi, shelf fungi

evolution of fungi

Plants, animals, and fungi trace their ancestry to protists

molecular data tells that animals and fungi shared a common ancestor after plants evolved

• Animals and fungi are more closely related to each other than either is to plants

• flagellated unicellular protist, was most likely the common ancestor

Structure of fungi

body(thallus) of most fungi is multicellular mycelium(yeast are unicellular)

Consist of vast network of threadlike hyphae

• septate fungi have hyphae with cross walls

• Coencytic (aseptate) fungi are multinucleated

• hyphae grow from tip

• help with absorption

Cell walls with chitin

Excess food stored as glycogen as in animals

Structure of spore generators

Sporangiophore- specialized fungi hyphae, stalk of sporangium

Sporangium- the structure of the enclosure unit where spores are

Spores- reproductive particles of the fungi

Reproduction of fungi

Fungi have both asexual and sexual stages of reproduction

Asexual- mitosis makes spore producing structures which germinate and produce more mycelium (usually involves windblown spores)

Sexual- plasmogamy (fusion of cytoplasm from haploid cells from two different mycelia) into the heterokaryotic stage. Then karyogamy (Nuclei fuse to form a diploid) into zygote(Diploid) stage. Meiosis where haploid spores are formed which germinate a multi cellular mycelium

Unicellular yeasts reproduce by budding

Zygomycota

Zygospore fungi

mainly saprotrophs decomposing animal and plant remains

ex. Rhizopus stolonifer is the bread mold

Chytridiomycota

Considered to be the most primitive fungi (500 million years old)

Chytrids are found everywhere. they synthesize and release digestive enzymes that break down molecules in the protective covers

some are part of the digestive flora of ruminants

microscopic, produce motile spores called zoospores

placed in protista kingdom before

Sac fungi

Ascomyctoa ~60,000 species

most are saprotrophs can digest cellulose, lignin, or collagen

most are composed of septate hyphae

morels and truffles, many plant diseases

Asperigillus and Candida cause serious infections: mycosis

Sac Fungi: Reproduction

Sexual reproduction: Ascus: fingerlike sac that develops during sexual reproduction and produce 8 Ascospores

Asexual reporduction is the norm

Yeast usually reproduce by budding

other ascomycota produce spores called conidia or conidiospores

Sac Fungi: molds

Can be helpful

Aspergillus is green molds used to produce soy sauce and citric acid

Species of penicillium is the source of penicillin

Sac Fungi: yeasts

Yeasts can be beneficial and harmful to humans

• Saccharomyces cerevisiae, are added to relatively sterile grape juice to make wine

• when yeasts ferment, produce ethanol carbon dioxide

• used in genetic engineering experiments

• Candida albicans is a yeast that causes fungal infections

• oral thrush is common in immunocompromised patients

Club fungi

Basidiomycota ~ 20,000 species

familiar toadstools, mushrooms, bracket fungi: some super poisonous

plant diseases such as the smuts and rusts

Mycelium composed of septate hyphae

Mycorrhizae

Mutualistic relationships between soil fungi and the roots of most familiar plants

• give plant greater absorptive surface

• help plants acquire mineral nutrients

• can be ecto(out) or endo(in)

80-90% plant species have mycorrhizal partners

fungal mycelia use their extensive network of hyphae and large surface area to channel water and minerals from the soil into the plant

in exchange the plant gives the products of photosynthesis to fuel the metabolism of the fungus

Endophytes release toxins that repel herbivores, or confer resistance to environmental stress factors, such as infection by microorganisms, drought, or heavy metals in soil

Lichens

not single organism, but rather an example of a mutualism in which a fungus (Ascomycota/ Basidomycota) lives in close contact with a photosynthetic organism(algae/cyanobacterium)

may be crust-like, hair-like, leaflike

a) upper cortex of fungal hyphae, which provides protection

b) algal zone where photosynthesis

c) medulla of fungal hyphae

d) lower cortex, which also provides protection

e) may have rhinzinae to anchor the thallus to the substrate

Parasitism, pathogens, and commensalism of fungi

fungi engage in both types of relationships, but fungi parasites can have lots of economic or environmental damage

plant infections from fungi

many plant pathogens are fungi that ruin crops and cause food spoilage and rotting of stored crops

Fungal infections

Common examples are ringworm

Trichophyton violaceum, causes superficial mycoses on scalp

Histoplasma Capsulatum is an ascomycete that infects airways and causes symptoms similar to influenza

Intro to seedless plants

Ancestors of Plants were green algae

Many evolutionary restraints from water to land:

• Avoid drying out

• needing structural support

• capturing sunlight

• dispersal of reproductive cells

Most seedless plants require moistness

Plant Phylogeny(seedless plants)

Alternations of generations

Haplontic refers to life cycle is where there is a dominant haploid stage

Diplontic refers to life cycle in which diploid is a dominany stage

Most plants switch between the two

Gametophyte-Haploid or Sporophyte-Diploid

Land Plant adaptations

Early land plants not more than a few inches off ground, they were nonvascular

Through the need to grow larger, plants made more rigid molecules, vascular tissues, that allowed for transport of water and other molecules through the plant

Xylem

Conduct water and minerals from soil up to the shoot

lignified for mechanical strength and impermeable to water

strengthened xylem can result in very large plants

Phloem

transport products of photosynthesis throughout the plant

consists of sieve elements (conducting cells) and supportive cells

Waxy Cuticle

protects leaves and stem from dessication, but stops CO₂ from coming into leaves

Stomata

breaks in the waxy cuticle that allow for CO₂ that can open or close

Protective flavonoids

Protect from photodynamic damage from UVB

Poisonous secondary metabolites(alkaloids)

deter predators

Sweet/nutritous metabolites

aids in pollination and dispersal of reproductive material through animals

Streptophytes

Land plants/closely related green algae

(Charophytes) are part of new mpnophyletic group “Streptophyta”

• both contain carotenoids and chlorophyll a and b

• both store carbohydrates as starch

Nonvascular plants/ bryophytes

Byrophytes thrive in moist habitats, some live in deserts

generally lack ligin and dont have vascular tissue, water and nutrients circulate inside specialized conducting cells

All conspicuous vegetative organs are gametophytes. sporophyte barely noticeable

three phyla: Hepaticophyta (Liverworts), Anthrocerotophyta(Hornworts), Bryophyta (mosses)

Reproduction of Bryophytes

gametophyte is dominant

• haploid egg and sperm\

• flagellated sperm will swim to the egg

• fertilization ends in sporophyte

Sporophyte is dependent on gametophyte

Vascular tissue

Tissue consists of conducting cells, tracheids and supportive filling tissues, parenchyma

Roots

Thin Rhizoids attach bryophytes to the substrate but dont provide strong anchor nor good absorption

true roots allow for an extensive network to water sources and stabilization for the plant

most form symbiotic relationship with mycorrhiza fungi or nitrogen-fixing bacteria in roots of legume plants

Leaves, Sporophylls, Strobili

Appearance of true leaves improved photosynthetic efficiency is the third inovations of seedless vascular plants< besides sporophytes and vascular tissue

Micophyll

first type of leaf that is small and has single unbranched vein that runs through the center of the leaf

Megaphylls

Larger leaves with a pattern of branching veins

Sporophylls

Leaves that are modified to bear sporangia

Strobili

cone-like structures that contain sporangia, mainly being the pine cone

Seedless vascular plants

Diploid sporophyte is the dominant phase, , reproduction still depend on water during fertilization, thus they like it damp

include : Club mosses, whisk ferns, horsetails, and ferns

Club Mosses

• the earliest group of seedless vascular plants

• small evergreen plants consisting of a stem and microphylls

• none are true mosses or byrophytes

Horsetails

Thin leaves originating from joint on plant

once used as scrubbing brushes because of silica in epidermal cells

Whisk ferns

• Psilotum nudum

• Conspicuous green stems with knob shaped sporangia

• lack both root and leaves

• DNA analysis say they are related to ferns

Ferns

• Most readily recognizable seedless vascular plants

• Considered most advanced seedless vascular plants, very close to seed plants

• some live in dry, most in moist

• sporophyte is dominant stage in life cycle,Fronds

• Sori, are small bumps with sporangium on the underside of fern frond

Importance of seedless plants

Mosses operate and help the tundra

byrophtes make soil more amenable to other plants

ferns contribute to environment: weathering of rock,accelerating making topsoil, and slowing down erosion

water ferns have nitrogen fixing bacteria and restore this important nutrient

dried peat moss used as fuel as renewable resource

florist uses sphagnum to maintain moisture in flowers

Evolution of seed plants

Gymnosperms and Angiosperms

• evolved from spore-bearing plants known as progymnosperms

Angiosperms are most recently evolved

Evolution of pollen and seeds

Seed

• protects and provides food for embryo

• Dormancy lets seed survive until hatching at the right moment

• Seed dispersal enhanced by fruits that coevolved with animals

Pollen

• Dispersal of sperm not dependent on water

More seed evolution

• Embryo protected by inegument

  • Extra layer or two of sporophyte tissue

  • Hardens into seed coat

• Also contains food supply for embryo

Evolution of seed plant gametophytes

2 kinds

Male(Micro) gametophytes

• within pollen grains

• dispersed by wind or pollinator

• no need for water

Female(mega) gametophytes

• develop within an ovule

• enclosed within diploid sporophyte tissue in angiosperms

Five phyla seed plants

Gymnosperms

• Coniferophyta

• Cycadophyta

• Gnetophyta

• Ginkophyta

Angiosperms

• Anthophyta

Gymnosperms

“Naked seeds”

Seperate female and male gametes

pollination by wind

lack flowers and fruits of angiosperms

all have ovule exposed on a scale

Conifers

Coniferophyta

spruces,pines,firs,cedars, and others

Cycads

Cycadophyta

Slow growing gymnosperms of tropical and subtropical regions

sporophytes resemble palm trees

Gnetophytes

Gnetophyta

only gymnosperms with vessels in their xylem

-contain three genera

• Ephedra

• Gnetum

• Welwitschia

Ginkgophytes

Ginkgophyta

only one living species remain

• flagellated sperm

• dioecious

  • Male and female reproductive structures form on different trees

Angiosperms

Flowering plants

1. monocots

2. dicots

Angiosperm life cycle

Difference between Monocot and dicot

1 cotyledons vs 2

Parallel veins vs netlike veins

vascular bundles complexly arranged vs in a ring

fibrous root system vs taproot

floral leaves in multiple of threes vs 4’s or 5’s

Monocots do not produce true word while Dicots do

True wood continued

true wood is made through secondary growth that expands the girth of the plant and creates true wood which proliferating xylem.

Features of the animal kingdom

• Multicellularity

• Complex tissue structure

• Heterotrophic

• active movement

• diversity in form and size

• Most exhibit sexual reproductionI(not sponges)

• offspring go through developmental stages

• determined/fixed body plan

Complex Tissue structure

Unique intracellular communication(gap Junctions)

• connective tissues

• epithelial tissues

• nervous tissues

• muscle tissue

Animal reproduction

Early development after zygote forms

Cleavage(series of mitotic cell division)

• cells continune to divide and/or rearrange

Blastula

• migration of cells-6 to 32-cell hollow ball

• blastocoel is internal cavity

Gastrulation-forms gastrula

• sets up formation of ectoderm and endoderm germ layers

• in most animals, mesoderm within remaing blastocoel

Features used to classify animals

1. symmetry

2. number of tissue layers

3. origin of mouth and smell

4. body plan and cavities

body symmetry

Asymmetrical

• Porifera(sponges)

Radial Symmetry

• arrangement around central axis

• oral vs aboral sides

• good for stationary or planktonic lifestyle

• cnidarians, ctenophores

Bilateral

• divides body into right and left halves

• allows for sense organs in head (cephalization)

• suited for all other animals and moving forward

Embryological development (tissues and symetry)

1. parazoa(beside animals)

   1. no true tissues or symmetry

   2. sponges(porifera)

2. Eumetazoa(true animals)

   1. remaining animals with distinct tissue

Embryological development (germ layers)

Radiata-diploblasts

• two germ layers- ectoderm and endoderm

• radial symmetry / Cnidarians, ctenophores

Bilaterata- triploblasts

• three germ layers- ectoderm, endoderm, and mesoderm

• bilateral./ all other animals

Endoderm

inner lining of most digestive tract organs, trachea, lungs

Mesoderm

all muscle, bone, cartilage, blood, most other visceral organs