BSC 1011 Unit 2

gamete evolution

different strategies for gamete production and fusion that developed in many plant-like protists. - isogamy, anisogamy, and oogamy

Division Coniferophyta

division of gymnosperms containing conifers and evergreens. - they are the oldest and tallest plants - needle-like leaves - important economically

division Ginkgophyta

division of gymnosperms containing the genus Ginkgo biloba, which is its only living species left.

oogamy

eggs are large and immobile, sperm are smaller and motile motile

syngamy

fertilization

cotyledons

first leaves produced by the embryo of a seed plant

phylum anthophyta

flowering plants

annuals

flowering plants that live for about a year. seed dispersal is less important for annuals, as the environment they are currently in is suitable for the parent plant

perennials

flowering plants that live for multiple years; seed dispersal is important

penicillium

fungi belonging to phylum ascomycota, which was used to produce the first antibiotic, penicillin

megaspores

one of 4 haploid spores formed from meiosis from a megasporangium, which develops into into a female gametophyte via mitosis.

Age of Gymnosperms

mesozoic era

genuses belonging to the ascomycota phylum

peziza, saccharomyces, claviceps, penicillium

alternation of generations

plant life cycle in which there is an alternation between a haploid gametophyte (n) and a diploid sporophyte (2n).

pollen

plant microspores, which are dispersed into the air (megaspores stay within the plant).

seedless vascular plants

plants that have vascular tissue but reproduce by spores. - club mosses, ferns, whisk ferns, and horsetails - have a xylem and phloem - leaves are microphylls or megaphylls

nonvascular plants

plants that lack vascular tissue, so they absorb water directly through its cells. - gametophyte is the dominant phase, and the sporophyte is nutritionally dependent on the gametophyte - often small and live in moist environments - release gametes into water

tube cell

produces pollen tube

angiosperms

"enclosed seed" plants, which produce flowers & fruits. - they are the largest plant group - include the phylum anthophyta

gymnosperms

"naked seed" plants, including conifers; they do not produce flowers, and their ovules/seeds are exposed

phylum deuteromycota

- "imperfect fungi" - molds, ringworm, predatory fungi - form many symbioses (mycorrhizae, lichens) - no known method of sexual reproduction - produce asexual condiospores

is pollination synonymous with fertilization?

no; every time pollination (sex) occurs, fertilization does not always occur. it is simply a process required to lead to fertilization.

phylum anthocerophyta

non-vascular plants (belonging to kingdom plantae) that are commonly known as hornworts

phylum hepatophyta

non-vascular plants (belonging to kingdom plantae) that are commonly known as liverworts

phylum bryophyta

non-vascular plants (belonging to kingdom plantae) that are commonly known as mosses

phylums of nonvascular plants

bryophyta, hepatophyta, and anthocerophyta

support tissue in plants

cellulose, lignin, and bark

basidium

club-shaped reproductive structure in which members of phylum basidiomycota produce spores

phylum ascomycota

- "sac fungi" (reproduce with ascocarp) - largest class of fungi - free-living and symbiotic - disperse spores by air - septate hyphae with perforations - morels, truffles - used in fermentation to make cheese, wine, and bread

kingdom plantae

- autotrophs with cellulose-based cell walls - green algae is their likely ancestor - colonized land 400 mya - classifications: non-vascular, seedless vascular, seed plants, seed "ferns", gymnosperms, and angiosperms

sporophyte

- diploid, multicelled individual formed from gamete fusion - produces haploid spores via meiosis for dispersal - spores germinate via mitosis to produce gametophytes - "adult" phase, which is what we are seeing from most plants right now - dominant form in higher plants (seedless vascular, ferns)

kingdom fungi

- heterotrophic unicellular and multicellular organisms - decomposers (and digest extracellularly) - chitin-based cell wall - saprobes (gain nutrients from dead organic matter) and symbionts (gain nutrients from living organic matter)

phylum zygomycota

- mostly coenocytic hyphae (have few or no septa) - disperse spores by air - include the genus rhizopus (black bread mold)

phylum basidiomycota

- mushrooms, toadstools, puffballs, bracket fungi - form fairy rings - disperse spores by air - septate hyphae

trends in alternation of generations

- plants moved from gametophyte dominance to sporophyte dominance - larger sporophyte and small, independent gametophytes - reduced gametophyte independence on sporophytes

how did seed plants evolve?

- pollination replaces swimming sperm to egg - seeds replaced spores, which was able to keep an embryo dormant, and keep it nourished and protected - gametophytes were protected and encased in the sporophytes

parts of a flower

- sepals, petals - stamen: anthers & filaments - pistil: stigma, style, ovary, and ovules

morphology of fungi

- thallus/mycelium: body - hyphae: filaments that make up the thallus/mycelium; can be septate or coenocytic - haustoria: specialized hyphae that release exo enzymes for extracellular digestion

seed life cycle

1.) an integrument megasporangium (contains unfertilized ovule) produces megaspore mother cells via meiosis. 2.) megaspores develop into gametophytes that produces egg/sperm. 3.) through the micropyle on the seed, a pollen grain containing the male gametophyte fertilizes the ovule by producing a tube to it via mitosis [?], turning the ovule into a seed

fern life history

1.) fertilization: sperm and egg come together, forming a diploid zygote 2.) at this point, the zygote can reproduce asexually or sexually, if sexually, the zygote divides via mitosis to form the diploid sporophyte (what we recognize as fern) 3.) the sporophyte will form sori, which contain clusters of sporangia, onto the fronds. inside the sporangia are spore mother cells, which will undergo meiosis to produce 4 unique haploid spores each. 3.) the spores germinate into a gametophyte (prothallus) that produces BOTH an archegonium and antheridium, which produce gametes (egg & sperm).

gymnosperm life cycle

1.) gymnosperm trees will produce both ovulate and pollen cones, which are the sporophytes. 2.) ovulate (female) cones: the sporophytes (cones) contain megasporangia. in the megasporangia, there are diploid mother spore cells that engage in meiosis to produce haploid megaspores. only 1 of the 4 spores produced will survive, and it will engulf the cytoplasm of the others to become large. pollen (male) cones: microsporangia (2n) contain microspore mother cells, which will undergo meiosis to produce 4 haploid microspores, which develop into pollen (the gametophyte that produces sperm). when a pollen reaches the ovule, the pollen grain germinates and forms a pollen tube, which it will later use to find its way to the egg. 3.) the spores produced will germninate via mitosis to form haploid mega- or microgametophytes, which will produce the egg and sperm.

problems that land plants face

1.) obtaining water 2.) transporting water and nutrients 3.) water loss 4.) gas exchange 5.) gravity 6.) reproduction 7.) temperature flux

zygomycota life cycle

1.) plasmogamy: a + and - individual's hyphae fuse

steps within alternation of generations (heterospory)

1.) two different gametes fuse, causing syngamy (fertilization) 2.) short dikaryon (n + n) phase, quickly followed after by karyogamy (fusing of the two nuclei), which creates a diploid zygote 3.) the diploid zygote continues to divide mitotically until producing the megasporophytes and microsporophytes, which will bear the micro and megasporangia (2n). 4.) the sporangia are a reproductive sacs that contains diploid mega/microspore mother cells. these mother cells can engage in meiosis to produce genetically unique haploid spores (not gametes!). if the plant is homosporous, there is simply a sporophyte that germinates into both an archegonium and antheridium 4.) the spores germinate and develop via mitotic divisions into a gametophyte, which can produce identical gametes via mitosis

features of land plants

1.) use chlorophyll a and b 2.) store food as starch 3.) protected gametes 4.) have stomata and root systems 5.) have wax surfaces, conduction tissue, and support tissue

microsporangium (pines)

2n sporangium containing microspore mother cells, which divide via meiosis to produce microspores, which develop into pollen grains.

the plant scene

300 mya, some seedless vascular and nonvascular plants experienced large, dense growth. much of the oil, coal, and gas deposits present today were formed by them.

divisions (phylums) of gymnosperms

Cycadophyta, Ginkgophyta, Gnetophyta, and Coniferophyta

gametic meiosis

a diploid individual produces haploid gametes; the gametes fuse to form a diploid zygote that divides to form another diploid individual. - this is the meiotic type of most animals.

seed

a fertilized egg/dormant embryo with surrounding nutrients protected from environmental conditions.

mycorrhizae

a mutualistic association of plant roots and fungus, which are often formed by fungi in the phylum deuteromycota

heterospory

a sporophyte that produces both microspores (germinates into a gametophyte that produces sperm) and megaspores (germinates into a gametophyte that produces eggs). - this is what most plants do.

homispory

a sporophyte that produces only one kind of spore, which germinates into a gametophyte. that gametophyte then produces eggs and sperm

lichens

a typically mutualistic association between fungi and algae or cyanobacteria. - algae provides food, fungi provides suitable environment for photosynthesis - "pioneer species" that help to transform environments into plant-friendly terrains - 3 forms: crustose, fruiticose, and foliose

zygotic meiosis

a zygote is formed by syngamy, which then undergoes meiosis to produce haploid spores - meiotic type of many fungi

sporic meiosis

alternation of generations; a diploid organism produces haploid spores via meiosis

what is unique about fern gametes?

although the sporophyte creates genetically unique spores, the gametophyte that develops out of it produces gametes via mitosis, so all of its gametes are genetically identical. ferns try to get around this by having the antheridium & archegonium develop at different times.

monocotyledons (monocots)

angiosperm flowering plants that develop from seeds having one cotyledon. - flower petals are in multiples of three - long, blade-like leaves with parallel venations

dicotyledons (dicots)

angiosperm flowering plants that develop from seeds having two cotyledons. - petals are in multiples of 4 or 5 - broad, narrow leaves with netted venations

angiosperm life cycle

angiosperms are heterosporous, so there will be the production of both male and female gametophytes. 1.) gametogenesis female: megasporangium inside the ovum contain megaspore mother cells, which divide by meiosis to produce 4 haploid megaspores. in embryo sac, one megaspore survives divides 2 and 1/2 times to produce 7 cells, which make up the female megagametophyte. one of the 7 does not divide and becomes larger than the rest and contains 2 nuclei, which later gives rise to the 3n endosperm. one of the 7 cells becomes the egg. male: in the anthers contain microsporangia, which contain microspore mother cells that undergo meiosis to form 4 haploid microspores. the microspores will be released into the air. if it reaches the female gametophyte, it will divide to become pollen grains (the haploid gametophyte). the pollen grains then produce produce a tube cell and a generative cell. the generative cell produces two sperm, and the tube cell forms the pollen tube. 2.) fertilization angiosperms undergo a "double fertilization", in which one sperm fertilizes the egg to form a zygote, and the other fertilizes the central cell, which results in the production of an endosperm (food supply). 3.) development of the embryo the zygote, which is now surrounded by a food supply (fruit), develops into an embryo. the embryo later germinates into a diploid sporophyte that can produce spores via meiosis.

reproduction of fungi

fungi reproduction can either be asexual (performed by "imperfect fungi") or sexual. *sexual*: 1.) cytoplasm of 2 different cell types fuse (plasmogamy), resulting in fertilization (syngamy). at this point, the cell has 2 nuclei (n + n; dikaryon). 2.) mitotic cell divisions occur before nuclei fuse 3.) karygamy: fusion of nuclei, which allows the cell to divide meiotically to produce spores

saprobes

fungi that absorb nutrients from dead organic matter

symbionts

fungi that gain nutrients from living organic matrer

plasmogamy

fusion of cytoplasm from two different cell individuals, which leads to fertilization (syngamy) during fungi reproduction

karyogamy

fusion of nuclei

ansiogamy

gametes are different in size and both are motile, but on different levels.

isogamy

gametes are equal in size and motility

vascular seed plants

gymnosperms and angiosperms

gametophyte

haploid, multicelled individual that produces gametes via mitosis. it is the dominant form in lower (non-vascular) plants.

ferns are an example of what type of plant?

homosporous

septate

hyphae whose cell walls partition into individual cells

coenocytic

hyphae with no cell wall partitions

generative cell

in a pollen grain, the cell that divides mitotically and forms two sperm cells

dikaryon/heterokaryon

in fungi reproduction, cells divide mitotically before the nuclei fuse during this transition (n + n) ploidy.

ascocarp

in sac fungi, the reproductive structure in which haploid nuclei fuse to form a zygote. formed by the sachs/spore sac

how do flowers ensure pollination?

insects and mammals help to disperse pollen and seeds via fruit.

microsporophylls

leaf-like structures that make up the microstrobilus and bears microsporangia, which contain the microspore mother cells.

megasporophylls

leaf/scale-like structures making up the megastrobilus. each "scale" contains one megasporangium.

phylums of seedless vascular plants

lycophyta, pterophyta, psilophyta, sphenophyta

seed ferns

may have evolved into today's seed plants

megagametogenesis

production of female plant gametes (pollen) via mitosis

gametogenesis

production of gametes

microgametogenesis

production of male plant gametes (pollen) via mitosis

sporogenesis

production of spores in the sporophyte by meiosis

isomorphic

refers to plants' alternating generations life cycle in which the sporophytes and gametophytes are indistinguishable in morphology

heteromorphic

refers to plants' alternating generations life cycle in which the sporophytes and gametophytes differ in morphology

fruits

ripened ovaries of flowers that help disperse seeds

phylum lycophyta

seedless vascular plants known as club mosses; have roots and leaves (microphylls)

phylum pterophyta

seedless vascular plants known as ferns; have roots and leaves as fronds (megaphylls)

phylum sphenophyta

seedless vascular plants known as horsetails; have roots, stems containing silica, and microphylls - genus Equisetum belongs to this phylum

phylum psilophyta

seedless vascular plants known as whisk ferns; have no roots or leaves. - since they lack leaves (important in photosynthesis), their whole stems are green.

what are the meiotic products of fungi?

spores

general fern life history

sporophyte → sori → sporangia → spores → gametophyte (prothallus) → archegonium (eggs) & antheridium (sperm)

micropyle

the opening to the ovule in seed plants, where the pollen enters

how are flowers and fruits beneficial to the plant?

their bright colors and patterns draw the attention of animals, and pollen/nectar/fruits reward those that make contact with them. when animals then travel to other places, they disperse the pollen or seeds from the fruit.

do plants undergo meiosis?

they do not undergo meiosis to produce gametes, but they do undergo meiosis to produce spores! spores are the source of genetic variation, and the male and female gametes formed from those spores are all genetically identical

seed plants

vascular plants that produce seeds (angiosperms and gymnosperms). - their gametes are protected in moist sporophytic reproductive tissues - seeds were changed as the dispersal agent (in the past, sperm swimming to eggs)

conductive tissue in plants

xylem and phloem

saccharomyces

yeast; phylum ascomycota