http://www.perspective.com/nature/plantae/

KINGDOM PLANTAE

Evolution • There are over 280,000 species of plants on

Earth.

• They are estimated to have evolved from green algae 450-630 million years ago.

• The fist plants to evolve where similar to mosses and reproduced using spores, an adaptation to being on land.

• Over time, selection favored plants that could tolerate dry land which lead to seed evolution.

• Plants with true seeds evolved around 390-320 million years ago.

• As selection began to favor plants with seeds a new adaptation was seen, flowers and fruits, around 130-200 million years ago.

• Some flowering plants have adapted to live back in the aquatic environment from wince they first evolved (aquatic angiosperms)

Life Cycle

• Plants have a life cycle that consists of alternating phases. “Alternating of Generations”

• Sporophyte (2N)

• Gametophyte (1N)

• In seeded plants the

sporophyte is the most

dominant form. The

gametophytes are

structures on the

sporophyte. (Ex. flowers)

Classification

• Botany is the study of plants.

• In botany, plants are classified into divisions instead of phyla.

• The divisions are based on three factors:

• Vascularization

• Seed Production

• Flowering

Embryophyta

LAND PLANTS

Embry0phytes • In general, land plants are: • autotrophs (photoautotrophs)

• reproduce asexually and sexually

• multicellular

• Phototropic- grow toward light

• cell walls made of cellulose

• The phyla of kingdom Plantae are divided into four major divisions… • Bryophyta

• Pteridophyta

• Gymnosperms

• Angiosperms

Bryophyta (the mosses) • Non Vascular

• Reproduce with Spores

• Includes the mosses, liverworts, and hornworts

Tracheophytes

VASCULAR PLANTS

Tracheophytes- Vascular plants

• Tracheophytes are land plants that have vascular tissue. They include all plants except for bryophytes.

• Vascular tissue forms vessels that carry water, plant products and nutrients up and down the plant.

• Xylem: Vessels that carry water and soil nutrients from the roots to the plant parts. (flows up!) They are always interior to the phloem.

• Phloem: Vessels that carry food (products of photosynthesis) form the leaves to the rest of the plant (flows down!) They are always exterior to the xylem.

• This allows them to grow taller/larger than non-vascular plants such as the bryophytes.

Pteridophyta (the ferns) • Vascular

• Reproduce with Spores

• Clubmosses, horsetails, and ferns.

Spermatophytes

SEED PRODUCING PLANTS

Spermatophytes • Spermatophytes are plants that reproduce

with seeds instead of spores.

• larger than spores.

• multicellular.

• produced by the fertilized gametes (ovules and pollen) of plants.

• germinate more easily than spores because they do not require much moisture.

• spread by the plant itself, animals, or the wind.

• can be naked or enclosed in the ovary of a flower/fruit.

• Two groups of seed producing plants angiosperms (enclosed) and gymnosperms (naked).

• http://news.nationalgeographic.com/news/2012/02/120221-oldest-seeds-regenerated-plants-science/

Gymnosperms (conifers) • Vascular

• Sporophyte dominant life-cycle

• Tend to be large and woody

• Reproduce with Seeds

• Includes conifers, cycads, Ginkgos, and Gnetales

Magnoliophyta

FLOWERING PLANTS

Flowers

• Stamen= male reproductive organ (pollen is released here)

• Pistal= female reproductive organ (ovule is housed here)

• http://www.mnh.si.edu/museum/news/firstflower/

Angiosperms (flowering plants) • Became the most dominant plant type about 60-100 million years

ago.

• The largest and most diverse division of plants.

• Come in two basic types: monocots and dicots

• Flowers are found on specialized stems called inflorescence.

• Autotrophic

• Vascular

• Flowering/fruiting

• Seed Reproduction

Heterotrophic Angiosperms

• Carnivorous/insectivorous Plants:

• Heterotrophic adaptation increases the growth and reproduction of the plant- most can grow strictly from autotrophic plant products but grow and reproduce better when heterotrophic.

• They capture prey and externally digest it, then absorb the nutrients.

• Parasitic and Saprophytic plants:

• Heterotrophic- some are still slightly autotrophic but some lack cholorphyll completely and are strictly heterotrophic

• Steal food, nutrients, and water from other plants

• Usually do not have roots

• Chemotrophic

Mimicry in Plants • There are many types of mimicry in the plant kingdom, most involve

attracting a pollinator or avoiding a predator.

• Plants have evolved that mimic the scents and appearances of other plants and animals.

• Mimicry gives them reproductive advantage. Those that closely resemble the characteristic that is being mimicked will survive and reproduce better than those that do not.

• http://labs.eeb.utoronto.ca/barrett/pdf/schb_54.pdf