Biodiversity Unit 2

Which organisms are the most significant recyclers on Earth?

fungi and bacteria

fungi

important ecologically as decomposers and recyclers. their primitive characteristics suggest that they are one of the earliest multicelled eukaryotes

Saprobes

organisms that gain nutrients by breaking down dead organic matter

Symbionts

Organisms that gain nutrients from living organic matter

3 main characteristics of kingdom fungi

decomposers, heterotrophs, chitin-based cell wall

3 general morphology pieces of kingdom fungi

thallus/mycelium, hyphae, haustoria

thallus/mycelium

body of fungus, anchors fungus in place

hyphae

tiny branching filaments that make up the thallus/mycelium

septate hyphae

contain cell walls that partition the cells

coenocytic hyphae

one continuous cell with many nuclei and no cell wall

haustoria

specialized hyphae that releases exoenzymes for multicellular digestion

syngamy

fusion of 2 haploid gametes to form a single diploid zygote

plasmogamy

1st stage of sexual reproduction in fungi, cytoplasms of 2 different parent cells fuse

ploidy

the number of different kinds of chromosomes in a species

dikaryon

2 unfused nuclei share the same cell

heterokaryon

any cell containing 2 genetically distinct nuclei

karyogamy

last stage in sexual reproduction in fungi, nuclei from two different cells fuse into one, and allowing meiosis to occur

meiosis

creates 4 unique sex cells for sexual reproduction

which phylums disperse their spores by air?

zygomycota, ascomycota, basidiomycota

phylum zygomycota

spores dispersed by air, hyphae with few or no septa (coenocytic), rhizopus, reproduction

rhizophus

phylum zygomycota, black bread mold

phylum ascomycota

largest class, free-living and symbiotic, septate hyphae w/ perforations, ascus/spore forms ascocarp, reproduction

ascus

sac that contains spores in phylum ascomycota

ascospores

sexual spores in phylum ascomycota

ascocarp

fruiting body in ascomycota

representatives of phylum ascomycota

peziza, saccharomyces/yeast, claviceps and rye ergot, penicillium, morels and truffles, cheese, wine, and bread

peziza

cup or saucer-shaped body without stems

saccharomyces

yeast, turns sugar into alcohol and carbon dioxide

claviceps and rye ergot

parasite that infects rye, wheat, and grains

penicillium

produces the first antibiotic, penicillin

phylum basidiomycota

spores dispersed by air, septate hyphae, basidium—basidiocarp, reproduction

basidiocarp

fruiting body of phylum basidiomycota

representatives of phylum basidiomycota

mushrooms, toadstools, puffballs, bracket fungi, fairy rings (world’s largest organism)

conidiospores

asexual reproductive cells used by fungi to spread and grow into new organisms

phylum deuteromycota

imperfect fungi, no observed sexual reproduction, produce asexual conidiospores

representatives of phylum deuteromycota

molds, ringworm, predatory fungus

2 types of significant fungal symbioses

mycorrhizae, lichens

mychorrhizae

mutualistic between roots of most plants and fungi- plants provide food for fungi and fungi enhance water and mineral uptake

lichens

mutualistic relationship between fungi and algae or cyanobacteria- algae provides food for fungi while fungi provides structure outside of regular algal habitats for growth

why are lichens considered “pioneer species”?

they help to establish terrestrial ecosystems by converting rocky environments to plant-friendly habitats

3 types of lichens

crustose, fruticose, foliose

characteristics of kingdom plantae

photosynthetic autotrophs w/ cellulose-based cell wall, alternation of generations, gamete evolution

what is the main difference in fertilization in plants vs fungi?

in plants, karyogamy occurs immediately before mitotic cell divisions- creating the diploid zygote

what are the products of meiotic cell division in plants?

spores

order of fertilization

sporophyte, spores, gametophyte, fertilization, zygote grows, repeat

sporophyte in the fertilization cycle

first stage, sporophyte (2n) uses meiosis to create spores

spores in the fertilization cycle

second stage, spores (n) grow through mitosis and eventually produce a gametophyte

gametophyte in the fertilization cycle

third stage, gametophyte (n) uses mitosis to make gametes (sperm + egg)

gametes in the fertilization cycle

fourth stage, sperm + egg fertilized and form a zygote (2n)

zygote in the fertilization cycle

zygote (2n) grows into new sporophyte, cycle repeats

homospory

sporophyte only produces one kind of spore that germinates into a gametophyte

heterospory

produces into 2 kinds of spores: megaspore, microspore

megaspore

germinates into a gametophyte individual that only produces eggs

microspore

germinates into a gametophyte individual that only produces sperm

2 types of gametophytes and sporophytes

isomorphic and heteromorphic

isomorphic

morphologically, the gametophyte and sporophyte and indistinguishable

heteromorphic

morphologically, the gametophyte and sporophyte are distinct

what can haploid cells not engage in?

meiosis because meiosis requires diploids for cell division

gamete evolution- isogamy

gametes are identical in size and mobility

gamete evolution- anisogamy

gametes differ in size but both are motile (unequally)

gamete evolution- oogamy

egg- large, immotile gamete

sperm- small, motile gamete

how long ago did land colonization by plants begin?

400 million years ago

what is a likely common ancestor of plants?

green algae (phylum chlorophyta)

what are some “new” problems facing “land” plants? (7)

obtaining water, transporting water and nutrients, water loss, gas exchange, gravity, reproduction, temperature flux

features of land plants (8)

chlorophyll A/B, starch storage, gametes protected, stomata, wax surfaces, root systems, conduction tissue, support tissue

nonvascular plants

lack vascular tissues, gametophyte to sporophyte, live in small and moist environments

significance of the gametophyte stage in nonvascular plants

the gametophyte stage is the main stage, it is longer lived and more noticeable than the sporophyte stage

3 types of nonvascular plants

phylum bryophyta (mosses), phylum heptatophyta (liverworts), phylum anthocerophyta (hornworts)

xylem in seedless vascular plants

vascular tissue that transports water and minerals from the roots to the stems and leaves

phloem in seedless vascular plants

vascular tissue that transports sugar made in photosynthesis from the leaves to the rest of the plant

microphylls

seedless vascular, small leaves

phylum lycophyta

club mosses- microphylls leaves, roots

phylum psilophyta

whisk ferns- no roots or leaves

phylum sphenophyta

horsetails, roots, leaves (microphylls), stems contain silica, equisetum

megaphylls

large, complex leaves

phylum pterophyta

ferns- roots, fronds (megaphylls)

fern life history cycle

sporophyte, sporangia, spores, gametophyte (prothallus), gametes, fertilization, repeat

2 reproductive structures formed from the fern’s prothallus

archegonium (produces egg), antheridium (produces sperm)

rhizome

underground roots of fern (phylum pterophyta)

which direction has the alternation of generation trend shifted?

gametophyte-dominant to sporophyte-dominant

terrestrial adaptations of seed plants

gametophytes are protected in moist sporophytic reproductive tissue, pollination replaced swimming for sperm delivery to egg

how did the seed evolve regarding terrestrial adaptations of seed plants?

it is protected and surrounded by nutrients, seeds dispersed replaced spores for reproduction

3 parts of the seed (fertilized ovule)

integument, megasporangium, megaspore

integument of seed

protective outer layer of ovule that turns into seed coat after fertilization

megasporangium of seed

structure where female reproductive process occurs

megaspore of seed

reproductive cell that develops into female gametophyte

heterokaryotic dikaryon

a cell with 2 nuclei that are different from eachother

Gymnosperms

“naked seed plant”, do not produce flowers, ovules/exposed

what plant is division cycadophyta, division gnetophyta, and division coniferophyta?

gymnosperm

what plant division is gingkophyta

gymnosperm, ex:ginkgo biloba

division coniferophyta

oldest, largest plant species, leaves form needles, important economically

what is the ovulate cone in division coniferophyta called?

megastrobilus

what is the micropyle in the pine life cycle and what is its function?

opening on the ovule that allows pollen to enter

division coniferophyta life cycle

megastrobilus, microspores/megaspores produced (sporogenesis), microspores, gametophyte, gametes (gametogenesis)

angiosperms

“enclosed seed plants”,phylum anthophyta, produce flowers and fruits, largest plant group, seed in a container “cotyledons”

cotyledon definition (angiosperms)

structure that provides nutrition for embryo plant

2 types of cotyledons

monocots- seeds have one cotyledon

ediocots- seeds have two cotyledons

in which plant group have fruits and flowers coevolved with animals to increase the plant’s success?

angiosperms

phylum anthophyta

“flowering plants”, flowers- sepals, petals