Chapter 25

Plant evolution and Diversity

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______ Are multicellular eukaryotic organism that are generally _____ and primarily live on land.

Plants; Photosynthetic

Algae

First clade after evolution of plastids are all aquatic _____

Land plants transition around 475 MYA, Common features:

1. Photosynthesis

2. Cellulose cell walls

3. Chlorophyll pigments a & b

4. Common enzymes

5. Common sperm structure

6. Starch as a carbon storage

Photosynthesis (chemical equation)

Co₂ + H₂0 —> C₆H₁₂O₆ + O₂

Terrestrial adaption

Transition to land required evolution of water-retention and gravity adaptions

Tissues

_____ arose from apical meristem at growing tips

Land plants (movement)

Generally sessile, land based

exception: sea grasses

Tissues

1.Lower SA/VR decreases water loss to air

2.Perform special functions

3.Produce bodies robust against drought and stress

Alternation of generations

Haploid or diploid phase

Multicellular

Alternation of generations (cycle)

1. The gametophyte produces haploid gametes by mitosis

2. Gametes fuse to form zygote

3. zygote develop into diploid sporophyte

4. The sporophyte produces haploid spores by meiosis

5. Spores germinate and divide to form the haploid gametophyte

Both plants and animals sperm and eggs are ______

Unicellular

Alternation of generation (plants)

Gametophytes reproduce sexually

Sporophytes reproduce asexually

In the course of evolution, The _______ has been reduced and the _______ has become more prominent

Gametophyte, Sporophyte

Sporopollenin

A highly resistant polymer that protects spores and pollen against drying and decay

Gametangia

Multicellular structure that encloses gametes and prevents them from drying out

Embryos

Young plants (new sporophytes) contained within protective structure

Embryos are present in ______ ______, Not _____ (Embryophytes)

Land plants, Algae

Fitness _____ as larger diploid individuals produces more spores

increases

Simplest - complex

1.Bryophytes

2.Vascular seedless plants

3.Gymnosperms

4.Angiosperms

Bryophytes

Liverworts, Mosses, Hornworts

Early plants

Water is necessary for sexual reproduction

Seedless vascular plants

Lycophytes and Pteridophytes

Possess stems, roots, leaves

Vascular systems

Lignified cells confer strength and ability to transport water against gravity

Lignified Tracheids

Fern and conifers

Lignified vessels

flowering plants

Xylem

Dead at maturity, Tissue carry water and minerals from the root to the rest of the plant

Phloem

Alive at maturity, Transport carbohydrates (Sucrose)

Vascular plants can maintain stable internal water content because of several adaptions:

1.Vascular system

2.Waxy cuticle

3.Stomata

Cuticle

A waxy coating external to the cell wall and limits water loss

Stomata

Closable openings that regulate gass exchange and water loss, allow CO2 in and water and oxygen out

_____ replaced seedless vascular plants as most dominant plants on earth

Gymnosperms

Seeds produce _____

Pollen

Gymnosperms

Lack flowers, fruits and endosperm

Cycads

Ginkgos

Gnetophytes

Conifers

Gymnosperm

Egg and sperm are contained in cones (naked seeds)

Pollen carried by wind brings sperm to fertilize egg to:

Embryo

Megastrobilus

Female cones (Far apart)

Microstrobilus

Male cones (close together)

Angiosperms

First flowering plants (roses and cacti)

Flowers and Fruits use other animals to help them disperse what?

Pollen and seeds

Cycads

Earliest diverging modern gymnosperm phylum, arose more then 300 mya

Many are endangered

Conifers

Seed cones

More then 50 genera

Cold and Dry climates

Gnetales

Gnetum

Ephedra

Welwitschia

Gnetum

Do not have broad leaves

Ephedra

Native to arid regions of southwestern US, adaptions to conserve water

Welwitschia

Only one living species which grows in the coastal Namib desert of southwestern Africa

Flowers

Foster seed production

Fruit

Favor seed dispersal

Endosperm

Food helps embryos within seeds grow to seedings

Sepals

Protect unopened buds

Petals

Attracting pollinators

Perianth Contain which parts of the flower

Petal and sepal

Carpels

Stigma

Style

Ovary

Ovule

Female megasporangia

Stamens

Anther

Filaments

Male Microsporangia

Pistil

One or several fused carpels

Perfect flower

Male(Microsporangia) and Female(Megasporangia)

Imperfect flower

Male or Female

Monoecious

Male and female on same plant (1 house)

Dioecious

Male and female are on different plants (2 house)

Angiosperms use a distinctive reproductive process called ______ ________

Double fertilization

Flowers evolved, resulting in a shift in what pollination?

Wind to animal

Secondary metabolites

Organic compounds that are not essential for basic cell structure and growth but aid in survival, structure and reproduction

Terpenes/Terpenoids

Citronella, rubber, turpentine, and amber

Phenolics

Responsible for colors and flavors

Alkaloids

Affect animals nervous system

Domestication

Process of artificial selection, where traits that are desirable to humans are selected.

Corn was domesticated from wild grass and arose from ______

Teosinte, which still grows in Mexico

Shattering

Ears of wild grains break apart and shatter their grains

Grains

Type of dry fruit