Lesson 13

Plants carry out some of the same functions as animals do to stay alive. Plants respond to the environment, exchange gases, transport water, make their own food, and reproduce.

Plant survivors All plants respond to changing conditions in their environment. Some plants have special designs that allow them to survive in the environments where other plants cannot.

The golden barrel cactus lives in very hot and dry deserts. When it rains, the cactus stores lots of water by opening itself up like an accordion. The waxy coating helps reduce water loss. The spines help shade the plant from the sun by making shadows.

The Venus flytrap lives in very poor soil conditions. When an insect touches the small hairs on a Venus flytrap, the leaf snaps shut and traps the insect. The plant releases Chemicals to break down the insect. After digestion, the leaf opens again.

Arctic plant survival Perennials Due to the short growing season, most tundra plants are perennials, they spend several years gathering and storing nutrients between each episode of seed production. Many can reproduce by sending runner through the soil, sprouting new plants at the nodes. This is less costly than blooming and producing seeds and fruit.

Heat Efficient To deal with cool summers, the flowers of Arctic dryad and Arctic poppy revolve slowly thought the long days, catching the sun’s rays.

Protective Covering Some plants, such as the wooly lousewort, protect themselves from wind, desiccation, and cold by growing thick “fur” that is made up thousands of tiny, curly hairs.

Nutrition Some tundra plants, such as Labrador tea and Arctic dryad, retain old leaves rather than dropping them. This conserves nutrients and helps protect the plant from cold, windscour and desiccation.

Questions Questions: What two ways does the cactus protect its water supply? waxy coating prevents water loss Needles provide shade Describe three ways that a Venus flytrap is like other plants. can reproduce leaves roots, stems, Describe one way it is different from most plants. Eats animals Describe one method that Arctic plants use to survive in a harsh climate. grows hair

Plant Responses A Plant’s reaction to its environment is called a Response

Root Response to Gravity. Plant roots support the plant and absorb water. Plants need to the water to help make food. The roots of most plants grow down. Roots respond to Gravity. Gravity is the force that causes things to try to move towards the center of Earth.

Flowers are part of the reproductive system plants and can develop into fruit in some plants. The stem provides structure and pathways for transport Leaves take part in photosynthesis, respiration and transpiration.