* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Diversity of Life
Photosynthesis wikipedia , lookup
History of herbalism wikipedia , lookup
Ecology of Banksia wikipedia , lookup
Plant stress measurement wikipedia , lookup
Gartons Agricultural Plant Breeders wikipedia , lookup
Plant use of endophytic fungi in defense wikipedia , lookup
History of botany wikipedia , lookup
Plant defense against herbivory wikipedia , lookup
Plant secondary metabolism wikipedia , lookup
Pollination wikipedia , lookup
Plant breeding wikipedia , lookup
Plant nutrition wikipedia , lookup
Historia Plantarum (Theophrastus) wikipedia , lookup
Plant physiology wikipedia , lookup
Plant ecology wikipedia , lookup
Evolutionary history of plants wikipedia , lookup
Ornamental bulbous plant wikipedia , lookup
Plant evolutionary developmental biology wikipedia , lookup
Plant morphology wikipedia , lookup
Sustainable landscaping wikipedia , lookup
Flowering plant wikipedia , lookup
Perovskia atriplicifolia wikipedia , lookup
Lesson 3.1 – What is a Plant? Oldest plants are 400 million years old. Contain chlorophyll, just like algae and some bacteria Most are autotrophs (producers) Most are multicellular All have cell walls Plants undergo photosynthesis -- recall that in this process, plants use sunlight, water, and carbon dioxide to produce food and oxygen. All plants (except green algae) have many cells organized into tissues. The cells differ from animal cells because they have a cell wall made of cellulose to make them stronger. They also have chloroplasts and a large central vacuole. Obtain water through roots. Retain water using the waterproof cuticle layer. Support their structure with cell walls and tissue. o Vascular tissue: xylem and phloem transport materials throughout the plant Reproduction in the absence of water. Lesson 3.2 – Classifying Plants Nonvascular plants: plants that lack vascular tissue to transport materials. Low-growing Thin cell walls Do not have roots for absorbing water Most live in damp, shady places and obtain materials from their surroundings. Most diverse NV plant (10,000+ species) Thin, root-like structures (rhizoids) anchor the moss and absorb materials. A slender stalk grows with a capsule at the end. o The capsule contains spores for reproduction. 8,000+ species “wort” means “plant” Shaped like a human liver Often found growing like a crust on moist rocks or soil. Less than 100 species Have curved structures (horns) growing out of the plant Usually live in moist soil Vascular plants have much more strength and stability than NV plants. Phloem moves food made in the leaves to other parts of the plant. Xylem moves water and minerals from the roots into the stems and leaves of the plant. Reproduce by using spores. 12,000+ species Shady, moist areas Stems, roots, and leaves; stems are mostly underground. Leaves are called fronds and are divided into smaller parts that look like small leaves. o Each frond has a cuticle to help retain water. Young leaves are called fiddleheads and uncurl as they mature. Have vascular tissue “ground pine” “princess pine” because it looks like a pine tree branch. Grow in woodlands and near streams. About 30 species Grows in a whorled pattern “scouring brushes” Have vascular tissues Use pollen and seeds to reproduce Roots, stems, and leaves Live in variety of climates Pollen: tiny structures containing cells that become sperm cells. Pollen delivers the sperm cells to the egg cells. After fertilization, seeds develop. o Seed: structure that contains a young plant inside a protective covering. Gymnosperm: a seed plant that produces naked seeds (not enclosed in a fruit). Needle-like or scale-like leaves Deep-growing roots Oldest type of seed plants (360 mya) Cycads: Grow mainly in tropical areas Look like palm trees with cones Conifers: Cone-bearing plants Most are evergreens that keeps their leaves or needles all year Largest and most diverse group Ginkgoes: Only one species, Ginkgo biloba Planted in cities because they tolerate air pollution Gnetophytes: Hot deserts and tropical rain forests Trees, shrubs, and vines Angiosperm: flowering plants; produce flowers and have seeds enclosed in fruits. Divided into two groups based on the number of cotyledons they have – seed leaves that provide food for the embryo inside the seed. Monocot: only have one seed leaf; grasses, lilies, and tulips are examples. Parallel veins Floral parts in multiples of 3 Vascular tissue scattered throughout stem Many roots that spread out Dicot: have two seed leaves; roses, maple trees, and apples are examples. Branched veins Floral parts in multiples of 4 or 5 Vascular tissue arranged in a ring One main root Lesson 3.3 – Plant Structures Functions: o Anchor the plant o Absorb water and minerals from soil o Store food Structure: o Root cap at the tip to protect the root o Root hairs grow out of the surface to absorb materials o Vascular tissue in the center of the root Desert roots spread far out but stay close to the surface so they can collect as much rain as possible. Forest roots do not need to spread out; they go deep into the ground to anchor the trees. Some trees have prop roots that begin above ground to keep them very secured. Many plants have fibrous roots which look like little tree branches; helps prevent soil erosion and water loss. Some plants have tap roots that grow straight down into the ground, so they are able to reach water deep in the ground. Function: o Carries substances using vascular tissue o Provides support for the plant o Holds up leaves to sun Structure: o Woody stems rigid (trees) are hard and • Outer layer of bark (cork) with cambium inside to produce new phloem and xylem layers. • Heartwood is at the center; inactive xylem used for support o Herbaceous stems are soft (most flowers) o Both types of vascular Structure: o Annual Rings: represent a tree’s growth; made of xylem. o Width of the rings can give info about the weather conditions that year. o Each ring represents one year. Function: o Capture sunlight o Photosynthesis Leaves have veins going through them, which hold the xylem and phloem. When the veins are full of water/nutrients, the plant does not wilt. The upper surface of the leaf: upper epidermis. Thin and flat; traps sunlight. Has a waxy covering which helps prevent water loss; called a cuticle. Below this layer is the palisade layer, which contains tightly packed cells containing chloroplasts. Then is the spongy layer, which has loosely packed cells to allow carbon dioxide to pass through the cells. The bottom layer is the lower epidermis. This layer contain several tiny pores, called stomata, that can open and close to allow water and gases to move in and out of the leaf. (transpiration) o Guard cells are located around the stomata, and change their shape forcing the stomata to open or close. Three main parts: o Embryo: young plant that develops from the zygote (fertilized egg) o Stored food: helps the embryo grow o Seed coat: outer covering of a seed; protects the seed from drying out Scattering of seeds – the further they go, the better chance for survival Animals eat food and the seeds are deposited in new areas Burrs around seeds get stuck in animal fur Wind and water carry seeds Germination: when the embryo begins to grow and push out of the seed Uses water and stored food to grow; first downward (roots), then upward (stem). Flower: reproductive structure; attracts insects and animals. Pollination: the transfer of pollen from male rep. structures to female rep. structures. Sepals: leafy structures that enclose flower before blooming; form base for flower. Petals: leafy structures arranged in a circle around the pistil; colorful to attract plant pollination. Stamen: male rep. part; filament-stalk and anthersproduces sperm cells. Pistil: female rep. part; ovary-at base, contains egg; stigma- where pollen attaches. Lesson 3.4 – Plant Reproduction Two stages: Sporophyte- the plant produces spores which develop into a gametophyte. Gametophyte- the plant produces two kinds of cells: sperm cells and egg cells (rep. cells). Angiosperms are classified based on the length of their life cycles. o Annuals: complete a life cycle in one growing season o Biennials: complete a life cycle in two growing seasons; first year they mostly grow roots, second year they grow taller with flowers. o Perennials: plants that live for more than two years All plants reproduce sexually with fertilization – when a male and female cell unite. the fertilized egg is a zygote. Some plants reproduce asexually. New plants grow from the roots, leaves, or stems of “parent plants”. Can happen quickly, but can lead to unfavorable traits (genetically identical). These plants need water in order for male cells to travel to female cells (produced by the gametophyte). Reproductive structures called cones – covered with scales; there are female and male cones. Male cones = pollen grains (sperm cells); female cones = ovules (contains 2 egg cells). Wind often carries pollen to a female cone, where the pollen gets stuck. The ovule encloses the pollen, and it fertilizes an egg. The zygote develops into an embryo. Female cones remain on the tree to allow the embryo (seed) to develop; the male cones usually fall off. When seeds mature, scales open and the wind carries them away. Pollen falls on a flower’s stigma (pollination). o Wind and other organisms, called pollinators, help this process. Sperm and egg join together in ovule (fertilization). Zygote develops as part of seed. Zygote develops as part of seed. Ovary changes into a fruit; the seeds are dispersed because of the fruit. Lesson 3.5 – Plant Responses and Growth Tropism: a plant’s growth response toward or away from a stimulus o Growing toward something is a positive tropism o Growing away from something is a negative tropism Called phototropism Leaves, stems, and flowers grow toward light The plant hormone auxin speeds the rate at which cells grow in response to light. Plant’s response to gravity; caused by the pull of gravity on cells at the end of the roots. Causes the roots to grow down and the stem to grow up. Without this, plants would not be able to grow from seeds. Some plants, like the Venus Flytrap and mimosa, respond to touch. The VF closes its leaves to trap insects when they land on it; the mimosa curls all of its leaves when it is touched. Short-day plants: need only a few hours of sunlight to grow. Long-day plants: need many hours of sunlight to grow. Day-neutral plants: can grow in any amount of sunlight. Dormancy: a period when an organism’s growth or activity stops. Cooler weather causes plants to stop making chlorophyll, changing green leaves into red, orange, and yellow. Lesson 3.6 – Plants in Everyday Life Food for people and animals Shelter for animals and insects Shade and oxygen Many other ways also! Green algae is used in scientific research and as a thickening agent in foods. Other plants are used to treat medical conditions. Gardening and agriculture Paper and lumber Linens, furniture, tires, etc.