Presentation on theme: "Chapter 22 Miller & Levine Text Biology 112"— Presentation transcript:
1Chapter 22 Miller & Levine Text Biology 112 Plant DiversityChapter 22Miller & Levine TextBiology 112
2Introduction to Plants Provide the base for food chains on landProvide shade, shelter and oxygen for all animalsOldest fossil evidence of plants dates from about 470 million years ago!What is the name of the science of studying plants??
3Kingdom Plantae Multicellular Eukaryotic Carry out photosynthesis using green pigments called chlorophyllInclude trees, shrubs, grasses, mosses and fernsMost are autotrophsCell Walls made of cellulose
4What do Plants Need? 1. Sunlight 2. Water & Minerals 3. Gas Exchange 4. Movement of Water and Nutrients
5Plant Life CycleTwo alternating phases, a diploid (2N) phase called the sporophyte generation and a hapoid (N) known as gametophyte generationThese alternating phases are known as “alternation of generations”
6Early PlantsFor most of Earth’s history plants did not exist. Life was concentrated in oceans, lakes and streams…Oxygen came from algae and cyanobacteriaThe first plants evolved from an organism much like the multicellular green algae living today.
7Overview of the Plant Kingdom Botanists divide the plant kingdom into 4 groups based on three important features:Water-conducting tissuesSeeds3. Flowers
9Types of Plants 235,000 Flowering Plants (Angiosperms) Cone-bearing plants 760 species (gymnosperms)Ferns & Relatives 11,000 speciesMosses & Relatives15,600 species
10Bryophytes (Non-Vascular) No Xylem or PhloemConfined to moist habitats b/c they need water for sexual reproductionCommonly found in wetlands, rain forests, and roadside ditchesGenerally less than 20cm tall3 classes: mosses, liverworts, and hornworts
13Bryophytes Have leaflike, stemlike and rootlike organs Have rhizoids (fine-like roots) that anchor the plantWater and nutrients move from cell to cell by diffusionMosses are the most common and they hold a lot of water – this sponge like feature makes them useful in oil spills, and potting soils
15Seedless Vascular Plants (Ferns & Relatives) Dominant land plant 300 million years agoMost are now extinct
16Seed Plants - Gymnosperm Divided into 2 groups: Gymnosperms & AngiospermsGYMNOSPERMS:The most ancient surviving seed plants are the gymnosperms (naked seeds)Seeds often found in a cone
17Gymnosperms: The Conifers Cone bearing woody trees and shrubsLeaves are usually needlelikeMost are evergreen (don’t drop their leaves in the Autumn)Conifers DO shed their needles, just not all at once – usually 2 to 4 yearsGrow in many different environments600 species (pine, fir, spruce, cedar, hemlock, sequoiasProduce useful products, ie. lumber/paper
18Seed Plant – Angiosperms: Flowering Plants There are thousands of different kinds of flowering plantsAngiosperms ALL produce seeds in reproductive structures called flowers.Flowers contain ovaries, which surround and protect the seed. Then, as the seeds mature, the flower changes into a fruit.The name angiosperm means “covered seed”Mature seeds are scattered, or dispersed, along with the fruit
19Monocots & DicotsBotanists are able to divide the 235,000 species of angiosperms into two large groups based on the structure of their seedsInside the seeds of angiosperms are tiny embryonic leaves called cotyledons. The seeds of one group of angiosperms have one cotyledon, called monocotyledons or monocots.Other angiosperms have two cotyledons. These are called dicotyledons or dicots
20The veins of monocot leaves are parallel to each other The leaves of dicots usually have netlike veins**See other characteristics on page 570
21Monocot ExamplesTulips, daffodils, irises, lilies, palm trees
22Dicot ExamplesButtercups, peas, roses, sunflowers, maple trees, and dandelions
23Grass?The leaf blade of grasses indicates whether they are monocots or dicots based on leaf veins.To which group to grasses belong?You are right if you said monocots!
24Roots, Stems & Leaves “Principal organs of seed plants”
25Roots – Try This: http://www.virted.org/Plants/RootsQuiz.html Absorbs water and dissolved nutrientsAnchors plants to groundPrevents erosionProtection from soil bacteria and fungusTransports water & nutrientsHolds plants upright against forces such as wind and rain
26Roots – Two main types: Plants have taproots, fibrous roots or both #1 Taproots - Characterized by having one main root (the taproot) from which smaller branch roots emerge. Make a plant hard to pull from the groundGo far underground to reach waterEx: dandelions, carrots, beets, radish
28#2. Fibrous Roots –Characterized by having a mass of similarly sized roots. Most monocots have fibrous root systems. Ex: grassesPlants with fibrous roots systems are excellent for erosion control, because the mass of roots cling to soil particles.
29Fibrous Roots - A cabbage seedling with white, fibrous roots snaking through the soil
33Leaves – (focus for Friday’s Lab) The structure of a leaf is optimized for absorbing light and carrying out photosynthesis.
34LeavesPhotosynthetic organ of the plant, used to convert sunlight into foodPhotosynthesis Equation:Stomata: pores within the leaf that open to let CO2 in and O2 out. Guard cells open and close.Cuticle: waxy covering on leaf that prevents water loss
35Vascular tissue= veins for the plant Phloem- transports food (sugar- 2ways)Xylem- transports water (1 way)No vascular tissueNo true roots, stems or leavesExample: MossSeeds = embryo surrounded by endosperm (food for the baby plant)Flowering plantsNon-flowering plantsMake cones, but no fruit or flowersExample: conifers, fir trees, pine trees, etc.Flower parts in 3 or multiples of 3Parallel veins in leafScattered vascular bundles in stem cross section1 cotyledon (seed leafEx. TulipFlower parts in 4/5 or multiples of 4/5Netted veins in leafRing of vascular bundles in stem cross section2 cotyledon (seed leafEx. Sunflower