Living Things and the Environment

Review 8

In your groups, answer the following questions

about your Arctic adaptation: 1. Is the adaptation structural, behavioral or

physiological? Explain why. 2. Why did that organism adapt that particular

trait? 3. How do you think that organism would be

different if it were in a desert instead of the Arctic?

Adaptations Review

Living things must be able to notice and react

to stimuli, such as sounds, chemicals, light or temperature changes in its environment.

Living things and the environment

You and your friends decide to play basketball

because the Sun has come out. Describe the stimulus and the response.

Thought Question 1

Tropism: a plants response to stimuli such as

moisture, light or gravity Phototropism Gravitotropism Heliotropism

Types of stimuli in plants

A plants response to light sources

Phototropism

The fact that all plants’ roots grow down and

their shoots grow up This is controlled by plant hormones called

auxins- they concentrate in the direction the plant should grow

Gravitotropism

A plant adjusts its leaves throughout the day

to catch the Sun’s rays

Heliotropism

During periods of droughts, plants need to

conserve their moisture. Would plants use heliotropism to orient their leaves parallel or perpendicular to the Sun’s rays? Explain your answer.

Thought Question 2

Animals show more complex responses to

stimuli than plants do. Even bacteria show complexity.

A taxis is a movement toward or away from a stimulus.

They’re different from plant tropism in that taxis involve the movement of the whole organism , not just part of it.

Chemotaxis

Stimulus and response in animals

Animals exhibit responses far more complex

than a tropism or taxis.

Animal responses to stimuli

Perhaps you have seen an animal, such as a

cat or an owl, get around pretty well at night. What are two differences in eye structure between typical nocturnal animals and that of a human?

Thought question 3

Use your laptops to research the following sensory organs or

structure. Fill in the type of sensory information that is collected, and write a brief description about how that information is processed. The first one has been completed for you:

Eyes: Light, color, shades of black and white; light is focused onto the retina, where rods and cones translate it into nerve impulses

Ears: Tongue: Fingertips: Nose:

Research sensory responses

In addition to

monitoring the external environment, an organism’s body constantly monitors and maintains its internal environment to keep itself alert and healthy.

Homeostasis

When your body senses a physiological

change, called negative feedback, it can stop the system from moving in the direction it’s going

Negative feedback

Innate behaviors are those that do not need to

be learned or taught. They are programmed within the organism’s central nervous system.

Examples: Taxis Reflex

Innate responses

More complex, innate animal behaviors

triggered by external stimuli.

Instincts

A colony of E. coli moves toward a source of

sugar. A pack of wolves sees one its members running with its head raised and tail straight out, and the other wolves begin to run toward the prey. In both cases, animals moved toward a source of food. How was the E. coli response different from the wolf pack response?

Thought Question 4

Some organisms release chemical messengers

called pheromones into their environments to communicate with members of their own species.

Hidden instincts

Taxes, reflexes, and instincts all have the

same fundamental purpose. What is this purpose?

Describe the major difference between a taxis and an instinctive response.

Thought Questions 5 & 6

Stimulus- external factor that affects an

organism Tropism- Plant’s response to stimuli Taxis- Animal’s response to stimuli

Reflex- nervous system reaction Instinct- more complex reaction to environment

Review

When things don’t come naturally, they must

be passed on from parents to their children through learned behaviors

Learned Behaviors

Some responses are learned, rather than

innate.

Conditioned responses

Mating rituals Territoriality

Schooling

Other complex animal behaviors

What are some instinctual behaviors of

humans? What are the least complex instincts called?

What are the most complex instincts called? Knowing how life developed, pose a theory

about how the complexity of instinctual behavior developed over the history of the world, from plants to humans.

Exit Ticket (Monday)