General Plant Characteristics Multicellular Eukaryotic Cell walls made of cellulose Autotrophs (photosynthesis) –Use chlorophyll a and chlorophyll b Life cycle is characterized by alternation of generations
Flowering plants Cone-bearing plants Ferns and their relatives Mosses and their relatives Green algae ancestor Flowers; Seeds Enclosed in Fruit Seeds Water-Conducting (Vascular) Tissue Plant Groups Green algae are thought to be the ancestors of plants -similar size, color, and appearance -Similar reproductive cycles -Identical cell walls and pigments used for photosynthesis
There are two major groups of land plants which are separated based on their adaptations that enable them to survive on land: Vascular Plants: have vascular tissue - internal tubes for transporting water and minerals from the ground. Examples: fern, oak trees, roses, grasses, etc. Cuticle: a waxy waterproof layer that prevents water being evaporated from plant. Non-Vascular Plants: Water enters plant directly through surface. They do not have roots. Rhizoids anchor plant. Example: moss Rhizoid Capsule Stalk Sporophyte Gametophyte Stemlike structure Leaflike structure Thought Question: Which group of plants is more limited in terms of how large the individual plant can grow?
Cone-bearing plants 760 species Ferns and their relatives 11,000 species Mosses and their relatives 15,600 species Flowering plants 235,000 species The Diversity of Plants How has this diagram changed over the last 200 million years?
Comparing Features of Seed Plants Feature Seeds Reproduction Examples Feature Seeds Reproduction Examples GymnospermsAngiosperms Bear their seeds on cones Can reproduce without water; male gametophytes are contained in pollen grains; fertilization occurs by pollination Conifers, cycads, and ginkgoes Bear their seeds within flowers Can reproduce without water; male gametophytes are contained in pollen grains; fertilization occurs by pollination Grasses, flowering trees and shrubs, wildflowers, cultivated flowers GYMNOSPERMS - (gymn = naked, sperm = seed) Male cones produce pollen that travel to the female cones which contain ovules. Seeds develop uncovered on scales within the female cones. ANGIOSPERMS - (angio = vessel, sperm - seed) Flowering plants produce their seeds using flowers. Many flowers have male and female organs. Seeds develop inside a protective, fleshy tissue called fruit. Many flowering plants rely on animals to pollinate them and some use wind pollination.
Filament Anther Stigma Style Ovary Carpel Petal Sepal Ovule Stamen The Structure of a Flower The reproductive structures of angiosperms are flowers. These structures all evolved as modifications of leaves. Sepal - a whorl of modified leaves that protects the flower bud before it opens. Petal - generally more brightly colored than sepals, advertise the flower to pollinators. Stamen - The pollen producing male reproductive organ of a flower, consisting of an anther & a filament. Carpel - The female reproductive organ of a flower, consisting of a stigma, style, & ovary.
Comparing Wind-pollinated and Animal-pollinated Plants Characteristics Pollination method Relative efficiency of pollination method Plant types Reproductive organs Adaptations that promote pollination Characteristics Pollination method Relative efficiency of pollination method Plant types Reproductive organs Adaptations that promote pollination Wind-pollinated Plants Wind pollination more pollen produced/ wasted, less decoration gymnosperms and angiosperms Cones or Simple Flowers Pollination drop Wind-pollinated Plants Wind pollination more pollen produced/ wasted, less decoration gymnosperms and angiosperms Cones or Simple Flowers Pollination drop Animal-pollinated Plants Vector pollination less pollen produced/ wasted, more decoration Angiosperms Flowers Bright colors, sweet nectar Animal-pollinated Plants Vector pollination less pollen produced/ wasted, more decoration Angiosperms Flowers Bright colors, sweet nectar Compare/Contrast Table Which pattern of macroevolution is demonstrated by this table? Why?
Haploid Diploid ??????? Spores (N) Sporophyte Plant (2N) Gametophyte Plant (N) FERTILIZATION Sperm (N) Eggs (N) Generalized Plant Life Cycle The generalized plant life cycle is described as alternation of generations. This is a life cycle in which there is both a multicellular diploid form, the sporophyte, and a multicellular haploid form, the gametophyte. The gametophyte produces gametes. The sporophyte produces spores. What cellular process is illustrated here?
Gametophyte (N) Sporophyte (2N) BryophytesFernsSeed plants Evolution of the Gametophyte and the Sporophyte
Review of Plant Evolution Thought Question: What is the evolutionary advantage associated with each of the derived characters shown in the cladogram below? Flowering plants Cone-bearing plants Ferns and their relatives Mosses and their relatives Green algae ancestor Flowers; Seeds Enclosed in Fruit Seeds Water-Conducting (Vascular) Tissue
Moss + relatives Fern + relatives Gymno- sperms Angio- sperms Characteristic Features No roots, stems, or leaves Spores produced by sporangia, have underground roots & stems, leaves above ground gymn - naked Sperm – seed Seed is exposed ang – vessel sperm – seed Seed is covered by fruit Fertilization Thin layer of water; sperm swims to egg (ovule) Some use swimming sperm, others use wind blown pollen Some use wind- blown pollen, others use animal vectors Dispersal of Offspring Spores blown by wind or carried by water Seeds blown by wind or carried by water Seeds blown by wind, carried by water or spread by animals Method of Getting Water and Minerals PoresRoots & vascular tissue Habitat Wet, moist Tolerates drier conditions Widely adapted: Aquatic to desert
Veins Xylem Phloem Vein Cuticle Epidermis Palisade mesophyll Epidermis Stoma Guard cells Spongy mesophyll The Internal Structure of a Leaf Thought Question: What materials enter the stoma? What materials leave it?
Stoma OpenStoma Closed Guard cells Inner cell wall Stoma Guard cells Inner cell wall Function of Guard Cells When water pressure is high, guard cells are forced into a curved shape and open the stoma When water pressure is low, the guard cells pull together and the stoma closes Photosynthesis = carbon dioxide in and oxygen out Cellular Respiration = oxygen in and carbon dioxide out
Evaporation of water molecules out of leaves. Pull of water molecules upward from the roots. AB Transpiration Thought Question: How does water get sucked-up the plant? Does the plant have to work (use ATP) do this? Explain.
Pulling It All Together 3. Transpiration – the movement of water out of the leaf, pulls water upward by osmosis 2. Capillary action – the tendency of water to rise in a thin tube cohesion – attraction between like molecules adhesion – attraction between different molecules 1. Root pressure and active transport cause water to move from the soil into the root What causes a plant to wilt?
Absorption of Light by Chlorophyll a and Chlorophyll b VBGYOR Chlorophyll b Chlorophyll a Chlorophyll is the type of pigment found in plants (pigments are molecules that absorb light). Chlorophyll Thought Questions: How does the wavelength of light absorbed and reflected by leaves related to the change of leaf color in the autumn? How does this relate to the pigments found in different types of algae at different depths of water?
Photosynthesis: Chloroplasts - bacteria sized organelle used for photosynthesis. The light dependent reactions take place in granum. Granum - Stacks of thylakoids where the first half of photosynthesis takes place, (light-dependant reactions). Stroma - The space around the thylakoids where the second half of photosynthesis takes place. (The Calvin Cycle)
Hydrogen Ion Movement Photosystem II Inner Thylakoid Space Thylakoid Membrane Stroma ATP synthase Electron Transport Chain Photosystem IATP Formation Chloroplast Light-Dependent Reactions Produce oxygen gas and convert ADP and NADP + into energy carriers ATP and NADPH. These reactions take place within the thylakoid membranes of chloroplasts.
ChloropIast CO 2 Enters the Cycle Energy Input 5-Carbon Molecules Regenerated Sugars and other compounds 6-Carbon Sugar Produced Calvin Cycle Uses ATP and NADPH from the light-dependant reactions to produce high- energy sugars. The Calvin Cycle takes place in the stroma of chloroplasts and does not require light. Factors Affecting Photosynthesis- Both temperature and the availability of water can affect rates of photosynthesis. Can you explain why?
Photosynthesis includes of take place in takes place in uses to produce use Light- dependent reactions Calvin cycle Thylakoid membranes StromaNADPH & CO2 ATP Energy from Sunlight and Water ATPNADPHO2O2 Chloroplasts High-energy sugars Thought Question: What factors will impact the rate of photosynthesis? What will cause the rate of photosynthesis to increase? Decrease?
Essays 1. a. Label letters A-J on the diagram of flower parts. b. Even though plants have to expend a lot of energy to make flowers, why is it still an evolutionary advantage to have flowers? Use the terms pollinators, pollination, fruit, seed dispersal, reproductive success, physical appearance in your response. 2. The evolution of Plants and Animals on land are strongly linked, particularly when it comes to the evolution of insects. Explain how the evolution of the first plants 470 million years ago, and the first vascular plants 410 million years ago, is linked to a major change in animal evolution. Also, explain how the evolution of a new group of plants 150 million years ago (with an adaptive radiation starting 65 million years ago) has led to the types of plants and animals that are common today. Some key terms to incorporate include: open niches, mass extinction, coevolution, and mutualism.