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Kingdom Plantae. http://www.perspective.com/nature/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.
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Kingdom Plantae http://www.perspective.com/nature/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