Ab botany

1. Ab botany • A. Overview of Plants: • All plants are multicellular, eukaryotic & • contain chlorophyll inside of chloroplasts. 2. Plants (also called autotrophs or producers) trap energy from the sun by photosynthesis & store it in organic compounds. (remember) 3. Heterotrophs or consumers get their energy directly or indirectly from plants.Plants also release oxygen needed by consumers. 4. Plants are very diverse & may be terrestrial or aquatic.Kingdom Plantae is divided into 12 phyla or Divisions.More than 270,000 plant species have been identified.

2. B. Plant evolution 1.Plants evolved from green algae

3. 2. Both algae & plants have chlorophyll a & b, have cell walls made of cellulose, and store energy as starch. 3. The First land plants had to develop adaptations to scarcity of water & climate changes (air temperature changes more rapidly than water temperature). 4. The origin of vascular tissue (specialized tissue for carrying food , water, & minerals) was an evolutionary breakthrough in the colonization of land.

5. 5. plants have a two-generation life cycle known as alternation of generations. -This means that a plant exists in 2 forms: the haploid generation is the gametophyte that produces gametes; and the diploid generation is the sporophyte that produces spores by meiosis.

8. 6. Most plants have vascular tissue (conducts water and other nutrients). Nonvascular plants are usually small and transfer materials by osmosis and diffusion. Examples include mosses and hornworts. 7. The earliest vascular plants reproduce with spores instead of seeds. An example is the fern.

10. 8. Vascular plants with seeds can be divided into two major groups: a. Gymnosperms= plants with naked seeds. -seeds do not develop in a fruit. Most develop in a cone. -examples – confiers (pines, spruces, junipers) and ginkgos. -gymnosperms are wind pollinated. Conifers produce two cones: female (seed) cone and male (pollen) cone.

12. b. Angiosperms – flowering plants. -seeds are enclosed in fruit. -flowers attract pollinators, ensure the transfer of pollen to egg, and aid in protecting seeps, pollen and egg. -examples: roses, mustards, legumes, etc

13. 9. Angiosperms are divided into two major categories: a. monocots- have a single cotyledon. examples include grasses, lilies, corn d. Dicots – have two cotyledons. Examples include many shrubs, trees

15. 10. Parts of a seed: -seed coat - protection -radicle – embryonic root -plumule – immature leaf -endosperm – fleshy inner tissue – for nutrients (in beans, peanuts, etc. the endosperm nutrients end up in the cotyledons.

17. 11. Parts of a typical flowering plant

18. 12. The three basic parts of a plant are the roots, shoots and leaves. • Roots function to anchor plants, absorb • water and minerals and some store • nutrients (carrots, sweet potatoes) -roots grow at the tips. A great source for cells undergoing mitosis.

20. b. Shoots (stems) – connect roots to leaves and have vascular tissue for the transport of nutrients, minerals and water. Shoots also provide structural support for a plant. -vascular tissue - • xylem- carries water and minerals up • a plant. Water is cohesive and adhesive • allowing it to “climb” the xylem. Also • transpiration of water out the leaves • and absorption by roots provides a • constant movement of water.

22. 2. Phloem – sugars and other organic molecules move down through the phloem. 3. Other tissues (cork, bark, cambium) provide strength and protection.

24. c. Leaves – the site for photosynthesis. -a typical leaf has a petiole (stem) and a leaf blade. The vascular system of the shoot passes through the petiole into the midrib (central vein) -the upper epidermis of a leaf is coated with awaxy layer of cutin. This helps keep water in. -within the leaf are layers of photosynthesizing cells -the lower epidermis has stomata (stomate = singular). These are openings that allow carbon dioxide in and allow water vapor out.