Exam 3 Botany

five major microevolutionary processes

1. mutation

2. gene flow

3. genetic drift

4. non-random mating

5. natural selection

What are the founder effect and bottlenecks an example of?

genetic drift

allopatric vs sympatric speciation

• allopatric: caused by geographic separation

• sympatric: no geographic separation

common mechanism for sympatric speciation in plants

polyploidy

polyploidy

double chromosome sets, due to nondisjunction in meiosis or mitosis

autopolyploidy

chromosome duplication in 1 species, leads to sympatric speciation

allopolyploidy

duplication of chromosomes between 2 sterile species (e.g. donkey and horse)

systematics

study of biodiversity and evolution

taxonomy

identifying, naming, and classifying species

classification

hierarchical grouping of species

What is included in a complete scientific name

genus and epithet

Why do we use scientific names instead of common names?

1. unambiguous

2. contain information about plant’s relationship

3. universally recognized

4. common names often have confusing information about relationships that aren’t related to evolutionary relationships

hierarchical levels of classification

Kingdom, phylum, class, order, family, genus, species

how are phylogenetic trees constructed

• monophyletic group (clade) is the common ancestor and all descendants

• closer together = closer relation

polyphyly

includes members from multiple lineages (e.g. homeotherm)

paraphyly

does not include all members of common ancestor (e.g. cold-blooded)

homologous vs analogous characters

• homologous: same origin, evolve different function

• analogous: different evolutionary origin, same function

what is algae

multi or unicellular photosynthetic protist

what photosynthetic organisms are not algae or plants?

cyanobacteria

sporic meiosis

produces haploid spores which divide mitotically, true plants do this

gamete vs spore

• gamete: haploid, has to fuse with another gamete to make a diploid zygote

• spore: haploid or diploid, grow to adult without fusion of another cell

zygote

gamete egg and spore come together to make an embryo

isogamy

gametes have identical morphology

anisogamy

gametes have different morphology

oogamy

gametes are highly differentiated (large, immobile egg and small, mobile sperm)

How are Charaphytes green algae similar to true plants

• similar cell division

• oogamous

• zygotes retained attached to parental gametophyte

• zygote cell walls have sporopollenin

• apical-like growth

How are Charaphytes green algae different to true plants

true plants have

• male and female gametangia

• keep zygote and developing embryo

• embryophytes

• multicell sporangia

• apical meristem tissue growth

path to make antheridia and archegonia

microsporangia → microspores → male/female gametangia → antheridia/archegonia

antheridia

male, many sperm

archegonia

female, 1 egg

gametophytes

come from spores and produce gametes by mitosis

• haploid

sporophytes

come from gametes, make spores, meiosis

• diploid

non-vascular plant's life cycle

1. male + female gamete fertilize

2. create zygote → sporophyte

3. sporophyte undergoes meiosis

4. creates M + F spores → gametophytes

5. create gametes - cycle

three phyla of non-vascular plants

Phylum Marchantiophyta - liverwort

• haploid meisospores → gametophyte

Phylum Anthocerophyta - hornworts

• sporophyte has continual growth, unicell rhizoids

Phylum Bryophyta - mosses

• multicell rhizoids, gametophytic leafy part, sporophytic stalk

adaptations needed for drier terrestrial life + larger size

• efficient conducting systems (xylem and phloem)

• structural support

• prevention of water loss

• specialized organs for photosynth, water and nutrient uptake

protostele

solid cylinder of vascular tissue with phloem surrounding or interspersed with xylem

• most ancient

siphonostele

pith surrounded by vascular tissue

• evolved from protostele

eustele

discrete vascular bundles around a central pith

• evolved from protostele

microphyll

1 vascular bundle/vein, arise from protostele

megaphyll

multiple vascular bundles/veins, arise from siphonostele and eustele

homospory

1 type of spore → M/F gametangia from gametophyte

heterospory

produces megaspore (male) or microspore (female) in different sizes

what do megaspores grow into

female gametophyte

what do microspores grow into

male gametophyte

sporocyte

spore mother cells undergo meiosis to create spores

sporophyll

leaves that have sporangia

strobili

concentration of sporophylls at tip (pinecones)

Sporopollenin

protective coat on spores

Megasporophyll

plant structure that holds female gametes/eggs

sporangia

enclosure where spores form

sporophyll

leaf or leaflike structure that holds sporangia

Microsporophyll

plant structure with capsule that holds male gametes/sperm

matrotrophy

maternal care during development

rhizome

analogous to roots, help hold onto substrate

sorus

cluster of sporangia