Ice Breaker • What are the characteristics of algae? • Prokaryote or Eukaryote? • Autotroph or Heterotroph? • Outside covered by a Cell Membrane or Cell Wall? • What do you know about plants? Chapter 8: Plants Mrs. Charney Northville Central School Flowers of the Day Foxglove Gerber Daisies Section One: The Plant Kingdom • Plant- autotrophic, eukaryotes, has many cells, undergo sexual reproduction, and surrounded by cell walls • What makes them different from algae? • They are adapted to live on land • Have ways to obtain and keep water • Can transport materials through their body Adaptations for Living On Land • Retaining Water- plants have a thick cuticle which is a waxy coating that helps to keep water in the plant • Transporting Materialsplants have a system in which water, minerals, and food move throughout the body • Xylem- water goes up • Phloem- food goes down Phloem Xylem Adaptations for Living on Land • Support- low-lying plants do not necessarily have this problem, but large plants and trees need to have rigid cell structures and vascular tissue (bark) • Reproduction- plants undergo sexual reproduction that can be fertilized within a dry environment • Zygote- a fertilized cell (sperm and egg are together) Classifying Plants • Non-Vascular Plantsplants that lack a good system for transporting materials up and down their bodies • Low-growing plants • Very slow method • Vascular Plants- plants that have true vascular tissue (xylem and phloem) • Plants are taller • Quicker method Do you think these trees would need vascular tissue? Partnered Ice Breaker • What are two characteristics of plants that make them similar to algae? • What is the difference between xylem and phloem? • What is the difference between nonvascular plants and vascular plants? Origin of Plants • Fossil evidence shows that green algae are ancestors of plants today Two Stages of Plant Life Cycles • Sporophyte- produces spores • Gametophyte- produces egg and sperm cells Section Two: Plants Without Seeds Pretty Flowers of the Day Hydrangea Black-Eyed Susan Types of Seedless Nonvascular Plants • Keep in mind that non-vascular plants do NOT have xylem and phloem • Three groups of Nonvascular Plants • Mosses • Liverworts • Hornworts • All three groups are low-growing and live in moist environments • Sporophyte grows right out of gametophyte Mosses • Most diverse group of nonvascular plants (10,000 species) • Rhizoid- thin, root-like structure anchor mosses and absorb water • Spores produced in a capsule at the top Liverworts • 8,000 species of liverworts • Sporophyte named after the shape of the human liver Hornworts • Less than 100 species of hornworts • Live among grass • Sporophyte looks like a horn Seedless Vascular Plants • Have vascular tissue • Reproduce by spores • Examples: • Ferns • Club Mosses • Horsetails Ferns • 12,000 species • Have true stems, roots, and leaves • Major part of the fern is the frond • Frond- leaves that are divided into many smaller parts that look like small leaves • Spores released from underside of leaves Frond Horsetails • Very few species left on Earth • Very hard, bristly leaves • Used by early Americans to clean their pots and pans Club Mosses • Only a few hundred species left on Earth • Unlike true mosses, these mosses do have vascular tissue • Looks like the small branch of a pine tree Ice Breaker • What is the difference between xylem and phloem? • What is the difference between a plant that is non-vascular and a plant that is vascular? Section 3: The Characteristics of Seed Plants What are Seed Plants? • Seed plants are all around you, and are very abundant • For every 1 seedless plant, there are 10 seed plants • Seed Plants • Have vascular tissue • Use pollen and seeds to reproduce • Have roots, stems, leaves Review of Vascular Tissue • Vascular tissuekeeps plants upright, and supplies cells with food, water, and minerals • Xylem- goes up, carries water • Phloem- goes down, carries food Ways of Reproduction • Unlike seedless plants (i.e. moss), seed plants can live in any environment • Seedless plants have to live in moist environments • Seed plants use the two following structures to reproduce: • Pollen- tiny structures that contain cells that will be sperm cells one day • Seed- a structure that contains a young plant inside a protective covering that keeps the plant from drying out • Seed Structure and Dispersal Inside of a seed is a partially developed plant • Three main parts: • Embryo- the young plant that develops from the zygote, or fertilized egg • Cotyledon- the leaves of a seed; sometimes food is stored in the cotyledon • Seed Coat- outer covering that protects the seed from drying out • Fruit- protects the whole seed • What are the three ways in which organisms move from place to place? • Seed Dispersal- Wind, water, other organisms • Plant Growth Germination- occurs when the seed begins to grow again, and pushes out of the seed • It is best that a seed plants itself away from its parent. Can you think of why would this be? • Does not have to compete with its parent • Spreads its species out over an area • Can you imagine if all of the pine trees in the Adirondack region were only located in the schoolyard of Northville? Roots • Three functions of roots: • Anchor the plant • Absorb water • Store food • Three types of roots • Fibrous- dense and tangled; take up a lot of space • Examples: grass, onions, corn • Taproot- one big, massive root that branches off into little smaller hair-like roots • Examples: dandelions, carrot Fibrous Tap Root Structure of Roots • Root Capprotects the root from injury as the root grows through the soil • Root Hairsincreases surface area so that more water and minerals are absorbed; also helps to anchor the plant better Stems • Stems- carries substances between plants roots and leaves; holds leaves up towards the sun • Two types of stems: • Herbaceous stemsoft (ex. Daffodils) • Woody stem- hard (ex. Maple tree, roses) • Cambium- located in woody stems that is found towards the outside; makes new xylem and phloem Ice Breaker • What are the three functions of roots? • What is the cotyledon in a seed? • What are the two ways of reproduction in a seed plant? • Tree Studies Examine the following wood samples…what do you see? • Each ring represents one year of growth • Dendrochronology- the study of tree growth by examining annual rings • Annual rings- circles in a tree that represent how old the tree is • One dark ring and one light ring make up one full year • Light ring- growth in spring; really rapid growth • Dark ring- growth in summer/fall; slower growth Summer/Fall Spring Leaves Leaves- capture the sun’s energy and carry out the food-making process of photosynthesis Leaves vary greatly depending on the tree Oak trees have really big leaves Pine trees have needles Palm trees have leaves that are big, but have small parts to it Parts of a Leaf Cuticle- prevents water loss Stomata- pores that open and close to control when gases leave (O2) and enter the cell (CO2) Transpiration- the process by which water evaporates from a plant’s leaves Stomata close during the day to prevent transpiration from the heat Stomata open at night when its cooler and there is less of a chance of transpiration Photosynthesis in Leaves Photosynthesis occurs at the top of the leaf, where there are more chloroplasts Section Four: Gymnosperm and Angiosperms Gymnosperms vs. Angiosperms • Think of a pine cone versus an apple • Although they are structurally different, they both contain seeds • Both are in different groups • Gymnosperms- produces “naked” seeds • Seeds are not enclosed within a fruit • Trees tend to have needlelike leaves, and deep roots • Example: pine tree, spruce tree Types of Gymnosperms • Cycads- grow in subtropical and tropical areas • All plants about 175 million years ago were cycads • Conifers- cone-bearing plants • Largest and most diverse of the gymnosperms • Ginkgoes- only one living tree today called Ginkgo biloba • Gnetophytes- live in dry areas • Can be either trees, shrubs, or vines • The plant Welwitschia can live for 1,000 years Reproduction in Gymnosperms • Cones- the gymnosperm reproductive structure that can be either male or female; covered in scales • Trees usually have both the male and female parts, but some trees just have one or the other • At the base of each female scale of a pinecone are ovules • Ovules- a structure that contains an egg cell • This will develop into a seed once it is fertilized Reproduction in Gymnosperms • Steps of reproduction in a gymnosperm are as follows… • Step One: Pollination- pollen transfers from the male structure to the female structure • Step Two: Fertilization- once the sperm meets the egg cell, the ovule closes off and seals it (the embryo forms) • Step Three: Seed Developmentfemale cones stay on the tree until they get mature; males fall off of the tree after they pollinate • Step Four: Seed Dispersal- when the seed is mature, the scales open up and release the seed out into the air to be picked up, carried to a new place, and form into a new plant Ice Breaker • Roughly explain the reproductive cycle of a gymnosperm Pretty Flowers of the Day Buttercup Petunia Angiosperms • Angiospermsflowering plants that have their seeds enclosed within fruits • Flower- the main purpose of a flower is for reproduction • Carries reproductive structures • Attracts insects to help pollinate Parts of Flowers • Sepal- located at the base of the flower; when the flower has not bloomed yet, it is contained within the sepal • Petals- colorful; this is the main part that attracts insects to the flower for pollination Male Parts of the Flower • Stamen- male reproductive part • Anther- top part where the pollen is produced • Filament- thin stalk where the anther sits on Female Parts of the Flower • Pistil- female part of the flower • Stigma (“sticky stigma”)- top where pollen sticks • Style- long tube where pollen travels down to fertilize ovaries • Ovary- where the egg and sperm cells join; protects the seed as it grows Reproduction in Angiosperms • Pollination• Pollen from an anther falls onto the “sticky stigma” • The pollen then grows a long tube down the style to the eggs • The sperm cells make their way down to the egg cells via the tube • Fertilization- the sperm and egg cells form (to make a zygote) and then begin to make an embryo within a seed • Fruit Development- as the seed develops in the ovary, the ovary then becomes a fruit • Fruit- a ripened ovary that protects seeds Major Groups of Angiosperms • Recall that cotyledons are the first leaves of a seed, and a place where embryos can get their food • Monocots- “one cotyledon” • Dicot- “two cotyledons” Differences Between Mono and Dicots Monocot Plant Part Dicot One cotyledon Seed Two cotyledon Parallel veins Leaf Branching veins Bundles of Vascular Tissue Scattered Stem Vascular Tissue Bundles of Vascular Tissue in Ring Flower Flower Parts in Fours or Fives Flower Parts in Threes Ice Breaker • What is the cotyledon difference between a monocot and dicot? • What is the leaf differences between a monocot and dicot? • Explain the reproduction in an angiosperm Pretty Flowers of the Day Tulip Water Lily Section 5: Plant Responses and Growth Tropisms • Think of… • Being pricked by a needle • You try to move away from the needle because it hurts • Being really cold, and a fire in the fireplace is burning in the next room • You move to the fire to warm up • Both the needle’s pain and the fire’s warmth is called a stimulus • Tropism: a plant’s response toward or away from a stimulus Types of Tropisms Yum! • Thigmotropism- a plant’s response to touch • Example: vines crawling up a wall, Venus Fly Trap • Phototropism- a plant’s response to light • Geotropism- a plant’s response to gravity Life Spans of Angiosperms • Annual- flowers that complete their life cycle in one year (only live for one year) • Examples- marigolds, petunias • Biennial- flowers that complete their life cycle in two years (only live for two years) • Examples- Celery, foxgloves • Perennials- flowers that live for more than two years • Example- Purple Coneflower, Maple tree Video Plants and People