Plants, fungi, and plant evolution

Most protists are

unicellular eukaryotes

Eukaryotic cells contain:

nucleus, membrane-bound organelles, mitochondria, plastids in photosynthetic species

Modes of Nutrition: Three main strategies

Autotrophic, Heterotrophic (absorption), Heterotrophic (ingestion), Some protists are mixotrophic (switch between autotrophic and heterotrophic)

Autotrophic

Produce food through photosynthesis

Autotrophic ex

algae

Heterotrophic (absorption)

absorb nutrients from environment

Heterotrophic (absorption) ex

fungi-like protists

Heterotrophic (ingestion)

engulf food via phagocytosis

Heterotrophic (ingestion) ex

protozoa

mixotrophic

switch between autotrophic and heterotrophic

Characteristics of asexual reproduction

Most reproduce by mitosis, allow rapid colonization, produces genetically identical offspring

Desiccation (drying out) leads to what adaptation

waxy cuticle

Gas exchange leads to what adaptation

stomata

Transport of water leads to what adaptation

vascular tissues

Anchoring to soil leads to what adaptation

roots

Support against gravity leads to what adaptation

lignin

Capturing sunlight leads to what adaptation

leaves

waxy layer preventing water loss

Stomata

pores controlled by guard cells that regulate gas exchange and water loss

two main types of vascular tissue:

xylem, and phloem

xylem

transports water and minerals

phloem

transports sugars produced by photosynthesis

Lignin

strengthens vascular tissues and allows plants to grow taller

Rhizoids characterisitics

root-like structures in nonvascular plants

Rhizoids function

anchorage and absorption

Roots characteristics

multicellular

Roots function

absorb water and nutrients, store food, and prevent soil erosion

Leaves functions

increase photosynthesis, capture sunlight, and contain stomata for gas exchange

Plants alternate between two multicellular stages

gametophyte and sporophyte

Gametophyte

haploid (n), produces gametes

sporophyte

diploid (2n), produces spores

Life Cycle Summary

1. Sporophyte produces haploid spores by meiosis

2. Spores grow into gametophytes

3. Gametophytes produce gametes by mitosis

4. Fertilization forms diploid zygote

5. Zygote develops into sporophyte

advantages of plant life cycle

increases genetic diversity, allows adaptation to different environments, spreads reproduction across two life stages

Bryophytes (nonvascular plants) ex

mosses, liverworts, hornworts

Bryophytes (nonvascular plants) characteristics

no vascular system, small size, rely on diffusion for water transport, reproduce via spores, gametophyte is the dominant stage

ferns (seedless vascular plants) characteristics

vascular tissues present, reproduce with spores, dominant sporophyte stage, leaves called fronds

ferns (seedless vascular plants) reproduction

spores produced in sori on fronds

Gymnosperms “naked seed” characteristics

seeds exposed on cones, wind pollination, two spore types: microspores and megaspores

Microspores

pollen, male on pine trees

Megaspores

eggs, female on pine trees

Angiosperms (flowering plants) characteristics

seeds enclosed in fruits, reproduction occurs in flowers, most diverse plant group

Angiosperms (flowering plants) flower parts

stamen and pistil

Stamen

male reproductive structure

Pistil

female reproductive structure

Spore characteristics

unicellular, grow into a gametophyte, little protection

Seed characteristics

multicellular embryo, grows into a sporophyte, protected with a food supply

What do seeds allow

plants to survive harsh conditions and disperse farther

Fungi characteristics

eukaryotic, heterotrophic decomposers, cell walls made of chitin, absorb nutrients from environment

fungi structures

hyphae, mycelium, fruiting body

Hyphae function

threadlike filaments

Mycelium function

forms the main body of the fungus, network of hyphae

fruiting body

reproductive structure

how are fungi reproduced

by spores

forms of spore dispersal

wind, water, animals

how can spores from

asexually and sexually