Plants and Their Adaptations

Variations of Parts

RootsLeavesSeed DispersalAttraction of PollinatorsPhototropismGeotropism

Survival

As you watch this presentation, focus on how variations, adaptations, or behaviors enhance a plants’ survival.

Include:Roots Seeds

Stems Phototropism

Leaves Geotropism

Flower

Variations

o Variation is:– the difference between individuals of the same species– the process or act of changing

o Variation is necessary:– If all of the plants in a species were exactly

the same, they could all be taken out by disease or disaster.

Structure and FunctionComparing structure and function of parts andbehaviors helps us understand why variation is

necessary.

Structure is the form of an organism’s parts. Example: A pedal is structured like a landing strip for insects.

Function is what that part does. Example: The function of a petal is to attract insects.

http://commons.wikimedia.org/wiki/File:Mature_flower_diagram.svg

Common Plant Parts

Most plants, no matter how they look, share some common parts.

Most plants have:

RootsStemsLeaves Flowers

http://commons.wikimedia.org/wiki/File:Leaves-scan.jpg

Structure and Function

The structure and function of plant

parts show evidence of adaptation.

Examples Include: Defenses against consumers

Ways to attract pollinators

Seed dispersal to ensure survival

http://commons.wikimedia.org/wiki/File:Weberocereus_tunilla_-_The_Cactaceae.jpg

RootsRoots must adapt to their different

environments.

• Structure and Function:– Roots act as anchors to keep plants grounded.

– Roots take in water and minerals from the soil through tiny root hairs.

– Some roots can store food.

http://commons.wikimedia.org/wiki/File:Cycads_root.png

RootsSome roots spread out along the ground in search of

water in places where it rains often.

http://commons.wikimedia.org/wiki/File:Root.png

Some roots grow deeper into the

ground in search of water inplaces wherethe climate is dry.

Roots

http://commons.wikimedia.org/wiki/File:Root_rot_in_cicer_arietinum_(hydro-grown).jpg

Roots

Some roots begin on a stem rather than below the ground. They are used for support to prop or brace the plant.

http://commons.wikimedia.org/wiki/File:Ghana_roots.JPG

Roots

Soil

Roots

Some plants are able to store food in their roots for later use. These are called storage

roots.

Some examples include: sweet potatoes

carrots

beets

radishes

http://commons.wikimedia.org/wiki/File:Rabano-radish-raphanus-sativus.jpg

StemsStems must adapt to whatever environment

the plant is in.

o Functions:– Hold the plant upright and

support the leaves– Carry water up the plant and

food down from the leaves to other parts of the plant

– Defend plants: thorns, prickles, and stinging hairs

http://commons.wikimedia.org/wiki/File:Cirsium_undulatum_(4990344551).jpg

StemsMany stems are edible like

asparagus, broccoli, cauliflower, and celery.

Cinnamon: The bark is used as a spice.

Garlic and Onion: They are bulbs.

Ginger Root: The edible portion is a branched underground stem called a rhizome.

Potato: The edible portion is an underground stem that is also a tuber.

Sassafras Tree: The shoots and stem bark can be used to make root beer.

http://commons.wikimedia.org/wiki/File:Dracaena_sanderiana_close_up.jpg

Leaves Leaves have many shapes and sizes, all depending

on the environment and how much sunlight the plant needs.

http://commons.wikimedia.org/wiki/File:Leaves-scan.jpg

Leaves

Functions:Make food through

photosynthesis and release oxygen

Protect the plant: prickles and spines

http://commons.wikimedia.org/wiki/File:Photosynthesis.gif

LeavesNotice how some leaves have adapted to

function as a defense.

http://commons.wikimedia.org/wiki/File:Erythrina_zeyheri,_blaarstekels,_Krugersdorp.jpg

Flowers

Functions:A flower helps the plant

reproduce.

The flower contains the pollen and egg necessary to make a fruit which has the seeds in it.

Structure of a Flower

Seeds

Seeds disperse differently depending on their structure:

Wind: Flowers can have a wing-like structure. Water: Flowers can have water-proof covering.Animals/Humans: Flowers can have burrs for

sticking to fur or clothing.Insects: Pollen sticks to insects as they move from

place to place.Some seeds can split and twist to throw seeds in all

directions.

SeedsWind: Maple seeds have a wing-like structure.

http://commons.wikimedia.org/wiki/File:Maple-seed.jpghttp://commons.wikimedia.org/wiki/File:Bumble_Bee_Gathering_Pollen.jpg

Insects: Pollen sticks easily to this bumble bee.

Seeds

Animals: This bison’s face is covered in cockleburs, which are the

Velcro®-like seed pods.

http://commons.wikimedia.org/wiki/File:Flickr_-_Furryscaly_-_Burface.jpghttp://commons.wikimedia.org/wiki/File:Sundari_seed.JPG

Water: The Heritiera littoralis seed has a water-proof covering.

Phototropism

Directional growth in response to the direction of the light source.

o Positive Phototropism: growth towards a light source– Plant shoot leaves exhibit positive

phototropism

o Negative Phototropism: growth away from light source – Roots usually exhibit negative

phototropism.

http://commons.wikimedia.org/wiki/File:Sunlight_on_Beech_roots_-_geograph.org.uk_-_1609346.jpg

http://commons.wikimedia.org/wiki/File:Phototropism.jpg

Geotropism Turning by a plant in response to gravity

oCharles Darwin documented the following:– Stems show negative geotropism (grow in opposite direction of gravitational pull)– Roots show positive geotropism (grow in direction of gravitational pull)

http://commons.wikimedia.org/wiki/File:Root_rot_in_cicer_arietinum_(hydro-grown).jpg

Sweet Potato PlantThis plant was sprouted in a shallow bowl of water in

a kitchen.

The leaves on the main sprout were facing the window and are reaching toward the light.The leaves on the

secondary sprouts are bending toward the light because they were facing away from the window.

The roots are reaching downward toward the ground. They are filling the bowl but always trying to go downward.