Plants

1. Plants biology

2. Plants • Multicellular eukaryote • Autotrophs-use photosynthesis • Thick cell wall made of cellulose • Specialized cells • Fungi • Multi or unicellular Eukaryote • Heterotrophs • Cell wall made of chitin

3. Hypothesized that plants came from Protista phylum of green algae. • Both use photosynthesis to make food and both are eukaryotes • They both have cells walls made of cellulose and use the same chlorophyll • Store food in the form of starch- a complex carbohydrate • Plants make the evolutionary leap to land around 440 million years ago

4. How to get out of the water ( Algae) without drying out (plants)? • Protect the outside- • plants adapted a thick waxy coating called a cuticle to protect against evaporation and damage from the sun

6. Get food- • use the leaf to carry out photosynthesis- bigger leaves means more photosynthesis, but more water loss. • How might this play a role in adaptations for cacti?

7. Get nutrients- • use the roots- a special organ in plants that gets water and minerals from the ground, but also holds it in place • Can also be used for storage of extra starches • Like carrots and potatoes

8. Nutrient transport- • Nonvascular- first to develop • Must be close to ground and water source • Plants are smaller and only a few cells thick • This allows for the faster transport of nutrients and water through diffusion and osmosis.

9. Vascular plants developed a stem- • a structure that allows for the quick transport of water and minerals from the roots to the leaves and sugars back down. • Also provides structural support to grow up instead of out • These organisms can live farther away from water and grow much bigger getting to more sunlight

10. Reproduction • Must protect gametes, no longer fertilize through the water • Make a seed- a protected gamete that contains the embryo and food source. • It can withstand heat and dryness • Seeds are not spores • Spores are haploid, but seeds are diploid • Plants use alteration of generation just like algae

11. Timeline for Evolution of Plants • Starts with nonvascular plants • Such as mosses and bryophytes • Simple cell arrangement close to ground to easily transfer water

12. Use alternation of generations • Only plant organism where the diploid sporophyte is dependent on the haploid gametophyte • Produce 2 sexual reproductive structures • Antheridium- male sperm produced • Archegonium- female eggs produced

16. Liverworts and Hepaticophyta • Thallose- broad flat structure- grow on damp soil • Leafy- thinner stems, mainly found in areas that have constant fog.

17. Hornwort- Anthocerphyta • Unlike the mosses and liverworts, the hornwort contains chloroplasts in its sporophyte so it makes its own food.

18. Non-seed Vascular Plants • Developed about 375 million years ago • Grow bigger and can move farther away from bodies of water • Taller means more sun and more photosynthesis

19. Vascular means that it has tubes inside of the organism that transfers water and nutrients throughout the plant. • Vascular plants are also sporophyte dominant • This means that the diploid (adult) is the main system that gets water and nutrients for the plant

20. Lycophyta- very similar to mosses- live close to ground and are photosynthetic • Diploid sporophyte is dominant • Contain leaves, stems, and roots • Leaves contain a small vascular tube to transport nutrients

21. Arthrophyta- horsetails • Small vascular plants with a dominant sporophyte growth • Its stem is hollow and can grow to about 3 feet tall • Reproduces spores like the lycophyta using the strobili- a non-photosynthetic structure on a leaf.

22. Pterophyta- or ferns- appear about 375 mya • Mostly live in moist areas • Sporophyte dominant life cycle • Main stem is underground called a rhizome- this stores starches and forms the root system • Fronds (leaves) grow from the large rhizome • Fronds have many different pinnae- small leaves • Ferns are first plants to have vascular tissue to each frond and pinnae

23. First seed plants are seen about 360 mya • Many died out • First conifers developed about 250 mya • First flowering plant are found about 140 mya

24. Seed plants are vascular plants that produce spores that are encased in a protective coating that contains nutrients for the developing embryo • Pollen grain- the male gametophyte • Ovule- the female gametophyte • They combine to make a diploid zygote • Why seeds?

25. Gymnosperms- seeds form on a cone • Include phyla • Cycadophyta, Gynkogophyta, Gnetophyta, Coniferophyta • Angiosperms- flowering plants- anthophyta • Produce seeds enclosed in a fruit • A fruit is the ripened ovary of a flower • Aids in the protection and dispersal of a seed. • Think about how you carry an orange from place to place?? • What about different types of seeds?

27. Parenchyma cell- most abundant in plants • Thin, flexible cell wall • Cells are mainly used as storage and food production • Store water, starches, and fats • Fruits and vegetables are composed of these • Many cells contain chloroplasts for photosynthesis

28. Collenchyma cells- long cells that can stretch • This is important because they provide structural support as the plant grows

29. Sclerenchyma cells- very think and rigid • Many die at maturity, but the thick cell wall remains for support of the plant • Can form fibers- like for rope and cloth • These are the gritty cells you get from pears

30. Dermal tissues • Epidermis- cells on the top of the plant that protect against water loss • Cells fit very tightly to keep water in • They form the waxy cuticle

32. Stomata- a structure that helps control water and gas exchange • Found on the underside of leaves. Why? • 2 Guard cells surround the stomata and open and close it as needed by the plant. Recall the gas exchange during photosynthesis

33. Small root hairs help to absorb nutrients as part of the dermis of plants • Stems and leaves that form a fuzzy layer called trichomes are used to protect against water loss and predations

34. Vascular tissues- for vascular plants only !!! • Xylem- a tube system that transports water and minerals • Phloem- a tube system that transports sugars through the plant • Read more on the helper cells in the book

35. Meristems- a new growth on the plant • Apical meristems- found near the tips of roots and stems and allow for the plant to grow in length • Lateral meristems allow the plant to get wider add diameter • Vascular cambium- produce new xylem and phloem as the plant gets wider • Cork cambium- produces tough cells that cover the plant as bark

37. Random info • Root cap- near the apical meristem of a root, allows for better protection of the apical meristem as the root grows through the ground

38. Stems- not all go upward and out • Tubers- a underground stem that can produce a new plant- can store nutrients, like a potato • Rhizomes- can store nutrients and they grow horizontally. AKA- stolon's and runners • This can produce many plants off of 1 stem, like ginger, bamboo, and poison oak • Any portion of a plants that stores sugars is called a sink

40. Leaf structure • Cuticle and epidermis protect the cells inside • The palisade mesophyll gets maximum exposure to the sun for photosynthesis • The spongy mesophyll are loose cells that allow for the movement of air and other materials through the leaf for photosynthesis • This is the layer in which most vascular structures run in the leaf • One more layer of epidermis covers the bottom along with the guard cells and stoma • No stoma on top, would cause too much transpiration

41. Plant responses to stimuli • Plant hormones regulate the growth and reproduction of plants • A hormone is a chemical that causes physiological change, or the change in the way the organism grows and acts

42. Different hormones cause different actions in the plant • Auxins- promote cell elongation, so new cells will get longer when the hormone is introduced • This hormone is diffused from one cell to another as the plant gets longer • Also controls fruit development, the reduction of side branches, and falling of leaves

43. Gibberellins- use for growing plant height • Seed development • Flower budding • Many businesses use the hormone to make things happen faster, like more fruits and more flowers in a shorter time. • Cytokines- cause mitosis to happen • Ethylene- a gas that causes fruits to ripen • Farmers will use the gas to make fruit ripen faster

44. Positive tropism- plants move towards, like sunlight • Consider how different hormones are used to elongate cells in a specific direction. • Negative tropism- plants move away, like other plants • Nastic movement- like the Venus fly trap

45. Other random facts • Plant alkaloids are toxins produced by plants that contain a nitrogen compound • Spicy food- capsaicin toxin • Cocainefrom the coco plant • codeine, morphine, opium- all produced by a toxin form the poppy plant • Nicotine, caffeine • Most of these toxins are found in the seeds of plants. • Household vegetables contain toxins, that in huge doses could hurt you- tomatoes are an example