Unit 8.1 - Responses to the Environment

Internal Cues come from inside the body.

For example:

Behavioral changes: A hungry animal searching for food, or a tired person falling asleep.

Physiological changes: Low blood sugar causing the body to release hormones that trigger hunger, or dehydration leading to thirst and water retention.

External Cues come from the enviroment.

For example:

Behavioral changes: Birds flying south in response to colder temperatures, or plants bending toward light.

Physiological changes: A lizard warming up in the sun to raise its body temperature, or pupils dilating in low light.

These responses help organisms maintain balance in their bodies (homeostasis) and improve their chances of survival.