Exam 2 Florence Wen // Bio153

Prokaryote Functions

-Break down organic material in dead plants and animals

-Release CO2 used by plants

-Make N available to most life forms

-O2 in atmosphere came from photosynthetic bacteria

How do prokaryotes benefit humans?

-Important to produce some foods

-Chemical reactions in industry

-Used for pharmaceutical products

-Bioremediation of polluted sites

Shared Characteristics of the 3 domains

Dna replication, ribosomes, plasma membrane

Kingdoms in Domain Archaea

Methanogens, Halophiles, Thermoacidophiles

Methanogen Environment

No oxygen, produce methane from H gas and CO2

Halophiles Environment

salty environments

Thermoacidophiles Environment

high temperatures

Why aren't viruses considered living?

-Cannot reproduce on their own

-Acellular

-No metabolism

-"Parasitic Chemicals"

How do prokaryotes reproduce?

binary fission

Endospore

when bacteria goes into a dormant state when environment is unfavorable

Endospores are resistant to

1) heat

2) drying

3) radiation

4) antibiotics

5) various chemical disenfectants

How do prokaryotes have genetic diversity

transformation, conjugation, and transduction

Transformation

a cell absorbs and integrates fragments of DNA from the environment

Conjugation

one cell directly transfers genes to another cell

Transduction

viruses transfer genes between prokaryotes

Gram-positive bacteria

Retain dye, appear purple, have a thick cell wall

Gram-negative bacteria

do not retain dye, appear pink, thin cell wall, usually more harmful to humans

How are 1/2 of prokaryotes motile?

Flagella

Cyanobacteria

-gram negative, blue-green algae

-photosynthetic, unicellular

-may be responsible for introducing oxygen to the atmosphere

-Produce harmful hepatotoxins and neurotoxins

Which domain is most closely related to eukaryotes?

archea

Are any archaea photosynthetic and are they known to cause infectious disease?

No

Kingdoms in Eukarya

Protista, Fungi, Plantae, Animalia

What do all eukaryotes have in common?

unicellular or multicellular, asexual and sexual reproduction, nucleus, membrane bound organelles

Characteristics of Protists

-Eukaryotic

-Mostly unicellular and aquatic

-Lack plant structures and animal features

-Make up plankton

Heterotrophic Plankton

zooplankton

Autotrophic plankton

phytoplankton

How do protists reproduce?

mostly asexual, but sexual in a stressful environment

"Plant-like" Protists

Green algae, Diatoms, Red Algae, Brown Algae, Dinoflagellates

Green Algae

mostly freshwater or moist land areas, photosynthetic, cell walls made of cellulose

diatom phylum?

Bacillariophyta

Diatom characteristics

most numerous unicellular organism in oceans, phytoplankton, cell walls made of silica, make O2

Red Algae

reddish, mostly marine and multicellular, eaten in Asia

brown algae

brownish, large, multicellular, includes kelp and other seaweeds, found on rocky coasts

Dinoflagellate Phylum

Pyrrophyta

Dinoflagellate characteristics

marine and freshwater abundant, most have 2 flagella, some heterotrophic

What is a red tide?

an algae bloom of dinoflagellates often resulting in dead marine life because of toxins

Protozoans

animal-like heterotrophic unicellular organisms classified by structure used for movement

Amoebiods Phylum

Rhizopoda

Ameobiod Characteristics

no cell wall, move with pseudopods and phagocytize food

ciliate phylum

ciliophora

Ciliates characteristics

beat in coordinated rhythm, use binary fission

sporozoan phylum

apicomplexa

Sporozoan Characteristics

non-motile, parasitic- form spores that are contained within cysts

Fungi characteristics

eukaryotic, heterotrophs through absorption, reproduce by spores, mostly multicellular

Are fungi more closely related to plants or animals?

Animals because both are:

-heterotrophic

-use oxygen

-use glycogen as energy reserve

-some animals have exoskeletons made of chitin (cell wall)

How are fungi different than plants?

-Lack chloroplasts

-Cell walls made of chitin instead of cellulose

-Energy reserve is glycogen instead of starch

asexual reproduction in fungi

grow as mold, clones produced by mitotic production of spores, or simple cell division (yeasts)

Chytrids (Chytridiomycota)

Found in freshwater and terrestrial habitats, can be a decomposer or a parasite, causes amphibian declines

Zygomytes

Mostly terrestrial, hyphae penetrate food and absorb nutrients

Ascomycetes

"sac fungi", spores produce in the sac, include morels and some yeasts.

Fruiting Body= ASCOCARP

Basidiomycetes

Mushrooms, shelf fungi, some mycorrhizae and molds. Defined by club-like structure, important decomposers of wood and other plant material. Produce spores externally

Fruiting Body= BASIDIOCARP

Deuteromycota

"Imperfect fungi", produce asexually, fermenters of cheese and alcohol and soy sauce. cause respiratory tract infections, athletes foot, and ringworm

Fungi form symbiotic relationships with

Lichens and mycorrhizae

Why are fungi important to the ecosystem?

decomposition (carbon cycle), mutualists with plants, tree diseases

why are fungi important to humans?

crop disease, spoilage of foods, on wood. cause fungal diseases, used to make antibiotics, used for cyclosporin (organ transplants, immunosuppressant), and bioprospecting (new medicine research)

Characteristics of plants

-eukaryotic, multicellular, photosynthetic

-chlorophyll a & b

-cellulose cell walls

-starch energy storage

-developing embryos protected by tissues of parent plants

-alternation of generations

Prerequisites for survival of plants

sunlight, CO2, water, inorganic nutrients

nonvascular seedless plants

Earliest terrestrial plants, lack roots stems or leaves, sporophyte is photosynthetic but cannot live apart from maternal gametophyte

3 phyla of bryophytes

mosses, liverworts, hornworts

How did bryophytes disperse?

wind dispersal, common in moist forests and wetlands. can inhabit extreme environments (mountaintops, tundra, deserts)

Mosses (byrophyta)

15,000 species, arctic to tropic regions mostly in damp shaded areas, can become dormant during droughts then rehydrate itself

Bryophyta structure

-"leafy" shoot

-dependent sporophyte consisting of foot, stalk, and sporangium.

Sporangium

site of meiosis and spore production. one sporangium can generate over 50 million spores

Hornworts (Anthocerophyta)

100 species, tall narrow sporophyte that remains attached to gametophyte, long-lived and has chlorophyll

Liverworts (Hepatophyta)

10,000 species

-Body flattened thallus or leafy appearance

-Sporophyte short lived, lacks chlorophyll

-Rhizoids (root-like structures)

-Anchors plants, absorbs some nutrients/water

Diplontic Life Cycle (Animals)

-only diploid stage is multicellular

-haploid cells are unicellular

Gametophyte reproduction

-Haploid (1n)

-Reproduce sexually

-Produce gametes

-Either male or female

-Antheridium (make sperm)

-Archegonia (make egg)

-Most noticeable, dominant phase of bryophyte life cycle

Sporophyte

-Diploid (2n)

-Reproduce asexually

-Produce spore (1n) via meiosis

-Sporangium (makes spores)

-Attached to parent gametophyte for water and nutrients

-Small, tucked inside female

step 1 of alternation of generations

Meiosis in sporophyte: produces haploid reproductive cells (spores)

step 2 of alternation of generations

Mitotic division of plant spore produces new gametophyte

step 3 alternation of generations

gametophyte (haploid): gametophytes produce gametes (egg and sperm)

step 4 of alternation of generations

fusion of egg and sperm during fertilization form a diploid zygote

step 5 of alternation of generations

Sporophyte

Vascular Plant successes

-water conservation systems

Vascular plant characteristics

-waxy cuticle

-stomata

-vascular systems

-sporophyte is dominant generation

-taller and larger than nonvascular plants

Xylem

-conduct water and minerals from roots

-flow is "upward" only

-dead hollow stacks of cells

Phloem

-Conduct sucrose and nutrients throughout plant

-Bidirectional flow

-Live tube for transport

Lignin

-strengthens cell walls of xylem

-provides decay resistance

seedless vascular plants

-reproduce sexually, release spores

-flagellated sperm

-sporophyte separates from gametophyte

-well developed vascular tissue

-dispersion by spores

Advantages of spore-dispersed plants

-cheap, small, decreases resource investment

-produced in high numbers and has high number of offspring

disadvantages of spore dispersed plants

-wasteful, small spores unsuccessful

-must land on good moist soil

-decreases resources to support growing gametophyte

When did Seedless Vascular Plants appear?

427 mya, Cooksonia

Club Mosses

Division Lycophyta

-1000 species

-Formerly very large in size

-All herbaceous

-Formerly woody

-Relicts of earliest vascular plants

Horsetails

Division Sphenophyta

-15 species

-Rhizome produces tall aerial stems

-Whorls of slender, green branches

-Small, scalelike leaves at joints

-Unchanged for over 300 million yrs.

Whisk Ferns

Division Psilophyta

-12 species

-Many extinct species known

-Lacks roots and leaves

-Simplest of seedless vascular plants

-Branches photosynthetic

Ferns

Division Pterophyta

-12,000 species (75% in tropics)

-Floating ferns to large tree-like ferns

-True roots, stems, and leaves

-Sporophyte separate from gametophyte

-Large conspicuous fronds (leaves), divided into leaflets, fiddlehead (young frond)

Sorl

Clusters of sporangia on the underside of ferns

Prothallus

heart shaped gametophyte fern. has rhizoids as anchor. antheridium and archegonium

Gymnosperms

The "Naked Seed" Plants, 800 species

Seed

-embryo sporophyte, food reserves, seed coat (protection)

-develops from "female" gametophyte

Pollen

immature male gametophyte

Heterosporous

-sharp differences between male microspores (pollen grains) and female megaspores

-pollen grain contains entire male gametophyte, including sperm

four divisions of extant gymnosperms

cycads, gingko, gnetophytes, conifers

Cycads

Division Cycodophyta, 185 species

-Short, palm-like trees

-Unbranched

-1 cone per tree, either male or female

-Flourished during Mesozoic

Dioecious

male and female structures on different plants

Monecious

male and female structures on same plant

Ginkgos

Division Ginkgophyta

-1 surviving species

-Unchanged for 200 million years

-Dioecious, some trees produce seeds and other produce pollen

-Male tree typically planted

Ginkgo Biloba

-considered oldest living tree

-improve mental functioning, ability to concentrate, and circulation of blood

-Chinese believe: strengthen lungs, kidneys, relieves cough, improves circulation

Gnetophytes

division gnetophyta

-70 species

-Three genera

-Ephedra (35), Gnetum (30), and Welwitschia (1)

Ephedra Sinica

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