Chapters 22, 23, & 25 Are eukaryotic, are multicellular, and have cell walls. Plants

Adaptations of plants Meristem– where new cells are found; tip of stem. Plants grow in response to environmental factors: –Light –Moisture –Gravity –Temperature

Adaptations of plants Some plants respond to chemicals or hormones. Auxin – is a hormone that makes stems grow toward light ad away from the pull of gravity. They make roots grow away from sunlight and toward the pull of gravity. Cytokinins – hormones that stimulate cell division and make dormant seed sprouts. Opposite of auxins.

Adaptations of plants Tropisms – response to gravity, light, and touch. Gravitropism – response of a plant to gravity. Ex. Roots grow into soil. Phototropism – response of a plant to light. Ex. Change in color; leaves fall off; grow in direction of light. Thigmotropism – plant’s response to touch. Ex. Venus flytrap.

Adaptations of plants Adaptations Aquatic plants – live in mud with little oxygen so have air-filled sacs that oxygen diffuses out of. Salt water plants – cells pump slat out of leaves. Desert plants – (xerophytes) tolerate heat, sand, winds and little rain. Seeds are often dormant. Carnivorous & Parasitic plants – soil has little nutrients so must trap & digest insects or live on a host plant to get nutrients. Epiphytes – not rooted in soil so grow directly on other plants. (not parasites) Many plants produce chemicals that are poisonous if eaten. Tobacco – Nicotine.

Classification of Plants

Plant Kingdom Flowering Plants Non-flowering Plants

Plant Life Cycle 2 phases –Sporophyte – diploid (2N) –Gametophyte – haploid (N) Alternating from diploid to haploid is called alternation of generations. Use energy from sunlight to carry out Photosynthesis.

A plant can be divided into 3 parts

. 3 groups FernsMossesGymnosperms Non - flowering Plants Do NOT produce flowers

Examples of Mosses

spores Spore-producing capsule

. No true roots, No vascular tissues (no transport) Characteristics of Mosses (Bryophytes). Simple stems & leaves. Have rhizoids for anchorage; no roots. Spores from capsules (wind-dispersal). Damp terrestrial land. Simplest plants

underground stem root A leaf (finely divided into small parts)

. True roots, feathery leaves & underground stems Characteristics of Ferns vascular tissues. have vascular tissues (transport & support) Dampshady. Damp & shady places Spore-producing organ. Spore-producing organ on the underside of leaves called a sporangia (reproduction)

needle-shaped leaves

Male cones (in clusters) Female cones (scattered)

. roots, woody stems Characteristics of Gymnosperms. needle-shaped leaves. tall evergreen trees. cones with reproductive structures. dry places. vascular tissues (transport). naked seeds in female cones

Angiosperms – Flowering Plants Have reproductive organs called flowers. Flowers attract animals which carry pollen (pollination). Seeds are protected and develops into a fruit. 2 groups – monocot (1 seed leaf)& dicot (2 seed leaves). Annuals (1 season), Biennials (2 seasons), Perennials (many years)

. 2 groups MonocotyledonsDicotyledons Flowering Plants. roots, stems, leaves. vascular tissues (transport). flowers, fruits (contain seeds)

Monocotyledons Parallel veins

. one seed-leaf Characteristics of Monocotyledons. leaves have parallel veins. herbaceous plants. e.g. grass, maize

Dicotyledons Veins in network

. two seed-leaves Characteristics of Dicotyledons. leaves have veins in network. e.g. trees, sunflower, rose

Roots, Stems, & Leaves Made up of: –Dermal tissue -“skin”; prevents water loss. – Vascular tissue -moves water & nutrients. –Ground Tissue – cells that lie b/w dermal & vascular. –Meristematic – responsible for new plant cells and growth.

Roots, Stems, & Leaves Roots: Seedlings grow into primary roots, then to secondary roots. Has a vascular cylinder (xylem & phloem). Function is to anchor plant to ground & absorb water and dissolved nutrients from the soil. Root pressure forces water upward.

Roots, Stems, & Leaves Stems: Function is to produce leaves, branches & flowers; hold leaves upright to sun; transport water & nutrients b/w roots and leaves. Monocot stems-vascular bundles are scattered throughout stem. Dicot stems-vascular bundles are in a ring & contain xylem and phloem tissue.

Roots, Stems, & Leaves Leaves: Plants main organs. Make food (photosynthesis). Have chloroplasts. Xylem and Phloem tissue are in bundles called veins which connect to the stem. Stomata allow air/gases in & out.

Transport in Plants Xylem – moves water. Phloem – moves sugars. Root pressure forces water up. Water is pulled up by a force called cohesion (molecules pulled together). Water molecules are also attracted to other molecules by adhesion. Capillary action is cohesion and adhesion together causing water to move upward. Water will move higher in a narrow tube than in a wider tube.

Plant Classification Non-flowering Plants Flowering Spore- bearing Naked seeds No roots with roots MossesFerns Gymnosperms 1 seed- leaf 2 seed- leaves MonocotsDicots