Plants Diversity

1. Plants Diversity

2. What is a plant? • Multicellular eukaryotes that have cell walls made of cellulose • Develop from multicellular embryos and carry out photosynthesis using the green pigment of chlorophyll

3. Plants include: • Trees • Shrubs • Grasses • Mosses • Ferns

4. What plants need to survive • Sunlight • Every plant needs sunlight to carry out photosynthesis • As a result, every plant has adaptations to gather sunlight, such as leaves • Water and Minerals • All cells require a constant supply of water • Photosynthesis requires water, sun also dries out leaves • As a result, plants have specialized structures that limit water loss and help with water uptake

5. What Plants Need to Survive • Gas Exchange • Plants require Oxygen for cellular respiration • Plants require Carbon Dioxide for photosynthesis • As a result, they have adaptations to help with gas exchange with the atmosphere while limiting evaporation • Movement of water and nutrients • Plants take up water and nutrients through their roots, but make food in their leaves • As a result, there are specialized structures that transport things in the plant

6. The Plant Life Cycle • Plants all alternate between 2 phases in their life cycles, a diploid stage called a sporophyte and a haploid stage called a gametophyte • Alternate between mitosis and meiosis to produce two types of reproductive cells—gametes and spores

8. Plant evolution theory • It is thought that the first plants evolved from an organism much like the multicellular algae living today, DNA research supports this theory as well 

9. This cladogram illustrates the evolutionary relationship between the 4 major divisions of plants Plant evolution

10. Bryophytes • Mosses and their relatives are called bryophytes or nonvascular plants • (Vascular tissue is specialized tissue used to conduct water and nutrients) • Life cycles depend on water for reproduction • Produce sperm that must swim through water to reach the eggs of another individual

11. Bryophytes • Can only draw up water by osmosis only a few centimetersabove the ground • Typically low-growing plants that are found in moist, shaded areas • Include Mosses, Liverworts, and Hornworts

12. Mosses • Grow best in moist environments • They can withstand colder climates • Are the most abundant plant type in polar regions • Have rhizoids instead of roots • Rhizoids are long thin cells that anchor the plant and absorb water and minerals

13. Both rely on moist environments and get their name from their shapes Liverworts and Hornworts

14. Bryophytes life cycle

15. Bryophytes life cycle • Just like most plants, bryophytes have a sporophyte and gametophyte stage • The gametophyte is dominant and carries out photosynthesis

16. Seedless Vascular Plants • Vascular tissue is specialized to conduct water and nutrients throughout a plant, these specialized cells are calledTracheids • Tracheids are hollow cells with thick cell walls that resist pressure • There are 2 types of vascular tissue made up of tracheids: Xylem and Phloem

17. Xylem and Phloem • Xylem is a transport subsystem that carries water upward from the roots to every part of the plant • Phloem transports solutions of nutrients and carbohydrates produced by photosynthesis • Both can move fluids through the plant body, even against the force of gravity

19. Seedless vascular plants include: • Club mosses, horsetails, and ferns

20. Club Mosses (lycophyta) • Are small plants that live in moist woodlands • Resemble miniature pine trees and are often called “ground pines”

21. Horsetails (arthryophyta) • Only has one living variety alive called Equisetum, because it looks like a horsetail and grows about 3 feet tall

22. Ferns (pterophyta) • Most diverse group of seedless vascular plants with over 11,000 different species living today • Have strong roots, rhizomes (underground stems), and large leave called fronds • Do well in low light and humid conditions

23. Life Cycle of Ferns/vascular plants • Have a life cycle that is dominated by the diploid sporophyte

24. Seed Plants • Have quickly become the most diverse group of species of organisms on land • Are divided into 2 distinct groups • 1. Gymnosperms: bear their seeds directly on the surfaces of cones, cone bearing plants • Include the pine, cycads, ginkgoes, and gnetophytes • 2. Angiosperms: known as flowering plants, bear their seeds within layers of tissue that protect the seed • Include grasses, flowering trees and shrubs, and all flowers

25. Reproduction is free from water • Adaptations that allow seed plants to reproduce without water include flowers or cones, the transfer of sperm by pollination, and the protection of embryos in seeds • Like all other types of plants, they have a life cycle that alternates between gametophyte and sporophyte stages • Cones and flowers are the sporophyte stage

26. Pollen • In seed plants the male gametophyte is contained in a tiny structure called a pollen grain • Pollen is carried by wind or insects to the female reproductive structures • Pollination is the transfer of pollen from the male reproductive structure to the female reproductive structure

27. Seeds • A seed is an embryo of a plant that is encased in a protective covering and surrounded by a supply of food • Typically there is a protective seed coat that prevents the he seed from drying out

28. Gymnosperms • Are the most ancient surviving seed plants • Gymnosperm means “naked seed,” referring to their exposed seeds • There are 4 varieties of gymnosperms

29. Gnetophytes • Only have 70 known types, are quite unique • They have reproductive scales that are clustered into cones

30. 2. Cycads • Are palm like plants that reproduce with large cones • Today there are only 9 genera in existence

31. 3. Ginkgoes • Contains only one living species, Ginkgo biloba

32. 4. Conifers • The most common gymnosperms, with 500+ species • Includes pines, spruces, firs, cedars, sequoias, redwoods, junipers, and yews • Some live over 4000 years (bristlecone pine)

33. Angiosperms—the Flowering Plants • All are members of the phylum anthophyta • Develop unique reproductive organs knows as flowers • Are an advantage because they attract animals that transport pollen from flower to flower • Flowers contain ovaries, which surround and protect the seeds • Ovaries develop into a fruit after pollination to protect the seed

34. Categorizing Angiosperms • There are 3 different grouping categories we use to classify angiosperms • 1. Monocot vsDicot • 2. Woody vs Herbaceous • 3. Annual, Biennial, Perennial

35. Monocot VS Dicot • Monocots and dicots are named for the number of seed leaves, or cotyledons, in the plant embryo • Moncots have 1 seed leaf, dicots have 2 • Cotyledon is the first leaf or the first pair of leaves produced by the embryo of a seed plant

36. Monocots Dicots • Single cotyledon • Parallel veins in leaves • Floral parts in multiples of 3 • Vascular bundles scattered throughout stem • Fibrous roots • 2 cotyledons • Branched veins • Floral parts in multiples of 4 or 5 • Vascular bundles arranged in a ring • Taproot

38. Woody VS Herbaceous Woody plants have cells with extremely thick cell walls that support the plant body, have the characteristic we call wood Includes all trees, shrubs, and vines (think grape vines) Herbaceous means that the plants do not produce wood as they grow A dandelion is a great example

39. Annuals, Biennials, and Perennials Annuals are flowering plants that complete their entire life cycle in a year Biennials are plants that complete their life cycle in 2 years Perennials are plant the live longer than 2 years Think?! What are the benefits to planting perennials in a garden?