Plants Botany = the study of plants

Plant Evolution Mosses and ferns Earliest relatives Cooksonia – 470 MYA Photosynthetic bacteria - as early as 1.5 BYA (billion years ago) Algae – around 750 MYA to 1 BYA (million years ago) All early plants were heavily dependent on water.

Nonvascular plants have no vessels, no roots, no stems or leaves. Examples: Mosses & Liverworts

Plant Adaptations to Land Vascular Tissue: Transport tissues; move water and nutrients to all parts of a plant Reproduction: Spores vs. Seeds Cuticle: A waxy outer covering that prevents water loss and provides protection Stomata: Openings on leaves that allow gas exchange As plants became larger and moved farther inland they had to adapt.

Vascular Tissue Xylem: transports water up Phloem: transports food & nutrients down

Xylem Phloem

Seedless Vascular plants have simple vessels, roots, stems and leaves but still reproduce using spores Examples: Club Mosses & Ferns

Seed Vascular plants have vessels, roots, stems and leaves. Reproduce using seeds. Examples: trees, bushes, flowers

Parts of the Plant Roots water and minerals are absorbed (taproots vs fibrous roots) also used to anchor the plant movement of water up to leaves is influenced by TRANSPIRATION, a process that moves water upwards

Stems Support plant transports water and nutrients Turgor pressure: the pressure inside a cell that is exerted by water Two types of stems: herbaceous and woody

A celery stalk soaked in food coloring will absorb the food coloring, you can see the xylem.

Leaves Where photosynthesis takes place; more specifically in the chloroplast Photosynthesis Equation:

Stomata: pores within the leaf that open to let CO2 in and O2 out. Water can also move through the stomata. Guard cells open and close. Cuticle: waxy covering on leaf that prevents water loss

Leaf Modification 1. Spines: 2. Color: 3. Shape:

How Plants Grow Germination occurs when a seed sprouts (usually caused by changes of temperature and moisture) Monocots have 1 seed leaf (cotyledon), Dicots have 2 seed leaves

Perennials - live several years, and reproduce many times, woody plants are perennials Annuals - a plant that completes its life cycle in one growing season (grows, flowers, reproduces and then dies) Biennials - takes two growing seasons to complete, it reproduces in the second growing season

PRIMARY GROWTH makes a plant taller at roots and stems; meristematic tissue SECONDARY GROWTH makes a plant wider, or adds woody tissue; vasular cambium tissue

Tree Rings tell the age of a tree, each ring represents a growing season. The photo shows a tree who has been through four growing seasons. The lighter thinner rings are winter periods. VASCULAR CAMBIUM: area of the tree that makes more xylem and phloem and forms the annual rings

Gymnosperms -"naked seeds" -cone bearing plants (seeds grow on cones) -needle like leaves -usually stay green year round -wind pollinated Examples: pine trees & evergreens

Angiosperms -flowering plants -seeds are enclosed in a fruit -most are pollinated by birds & bees -have finite growing seasons Examples: grasses, tulips, oaks, dandelions

Flowering Plants are divided into two main groups:

Monocots

Dicots

Flower /Pistil

Plant Reproduction Pollen is produced by the stamen, which is carried by wind or pollinators to the stigma of another flower. Once the ovules are fertilized, they develop into seeds and the ovary of the flower becomes the FRUIT

Pollen Grains Pollen contains plant sperm, and fills the air during the springtime, which often causes seasonal allergies.

Asexual Reproduction Many plants can make clones of themselves; this is called VEGETATIVE PROPAGATION

Plant Hormones Auxin – makes roots form and buds grow, important in trophic responses; also effects when fruit are dropped from a plant Gibberellin – growth hormone; effects height of the plant Ethylene – effects rippening of fruit Cytokines – effects the rate of cell division

Plant Responses Nastic Response – a response that causes movement but does not depend on the direction of the stimulus Ex: flowers opening and closing from day to night to conserve heat; Mimosa plant responds to touch

Plant Responses Trophic Response – a plants response to a stimuli (copy the information from Table 4 into your notes)