Plant Adaptations Trees shrubs grass moss ferns Importance

Plant Adaptations Trees, shrubs, grass, moss, ferns

Importance of plants n Earth’s major producers n Food and shelter for many organisms n Supply O 2 needed for cellular respiration

Characteristics of Plants n Eukaryotic n Multicellular n Autotrophs n Cell walls made of cellulose u. Remember fungi & bacteria?

Theory—plants evolved from green algae (one of the plant-like protists) about 500 million years ago.

Similarities btwn plants & green algae: n n n Have cell walls made of cellulose Have the same types of chlorophyll used in photosynthesis Store food as starch

Some differences: n Green algae needs water constantly for photosynthesis & reproduction n Have no structures to prevent drying out What characteristics allow land plants to over come these obstacles?

Adaptations of landliving plants 1. Structures that provide plant with food, water, and minerals – leaves & roots.

Leaves n Broad, flat organ that traps light energy n Cells contain 1000 s of chloroplasts (photosynthesis) n Location for most photosynthesis in plants

Adaptations of Leaves The leaf of the pitcher plant is modified to attract & then digest insects & other small prey due to lack of nitrogen. Plants that grow on forest floors produces broad leaves to capture the small amount of sunlight that penetrates between taller trees

Roots n Plant organ that: u Anchors plant in ground u Absorbs water & minerals from soil (assisted by root hairs) u Transports nutrients to stem

Adaptations of Roots Exposed to air, ex. Epiphytes Usually for plants that need to grow on top of other plants to reach sunlight. Must get water from rain or mist because they are not in the soil. • Ex. Orchid Swollen portions that can have buds to produce new shoots. Ex. Tubers, radish, potato, rutabaga

2. Structures that aid in the transport of materials stem & vascular tissues.

Stem n Provides structural support for upright growth n Some green stems may also carry out photosynthesis n Contains tissues for transporting food, water, and nutrients from one part of the plant to another

Water moves from the roots to the leaves (what occurs in the leaves and what does it produce? ) Through xylem tissue

The sugars/food produced in the leaves move to the roots through the phloem tissue.

Summary Substance Water Food/Sugar Direction Leaves Roots Vascular Tissue Xylem Phloem

Adaptations of the Stem A tuber is a stem, usually growing underground, that stores food. Ex. potato A rhizome is a horizontal, underground stem. New shoots can form allowing the plant to undergo periods of dormancy. Ex. ginger

A bulb is made up of a central stem surrounded by short, thick leaves. that protect the bulb & store food. Ex. Onion, garlic

Tropism – movement of plant in response to environmental stimulus • • Controlled by hormones 3 Types of tropism 1. Photo- light example: stem grows towards light 2. Gravit- gravity example: Roots grow towards Earth 3. Thigmo- touch example: Climbing vines

3. Structures that help prevent water loss - cuticle & stomata

Cuticle n Protective waxy layer on leaves n Prevent evaporation & tissues from drying out

Stomata n Openings in the cuticle of the leaf n Regulated by guard cells - allow for gas exchange during photosynthesis n Can close to prevent water loss – transpiration Stomata & guard cells

Adaptations of the Leaves The narrow leaves of a pine tree contain a waxy epidermis as well as stomata shrunken below the surface of leaf to reduce water loss. Cactus and other succulents have a tick waxy coating and reduced leaves to prevent water loss in arid climates.

4. Structures for reproduction w/out water - flowers

Most flowers have 4 basic parts. petals pistil/ carpel stamen sepals

Adaptations of Flowers Brightly colored and sweet nectar to attract pollinators Development of fruit for seed dispersal

Flowers & Pollinators n Wind pollination - not very efficient; usually produce vast amounts of pollen to help ensure pollination; ex. Oak trees n Animal pollination - Most angiosperms are pollinated by animals - mainly insects, birds, bats - they carry pollen from one flower to another.

n Animals have evolved body shapes that enable them to reach deep within certain flowers, ex. Hummingbirds

Different fruits n Fleshy fruits - apples, grapes, melons, tomatoes, squash, cucumbers n Dry fruits – peanuts, walnuts, wheat, barley, corn, rice

Seed Dispersal n By animals - Seeds contained in sweet, fleshy fruits. Seeds are covered with tough coatings that protect them from digestive chemicals. Then the seeds sprout in the feces eliminated from the animal.

n By wind & water - Seeds are typically lightweight, allowing them to be carried in the air or to float on the surface of the water