Proximate mechanisms

Question 1

What are proximate causes in animal behaviour?

Answer 1

Immediate causes or mechanisms that directly contribute to a behaviour or trait, including physiological and environmental factors.

Question 2

What are ultimate causes in animal behaviour?

Answer 2

Evolutionary forces that have shaped a behaviour or trait over time.

Question 3

How do testosterone levels relate to behaviour?

Answer 3

Testosterone levels correlate with aggression in many animals from fish to mammals (a proximate mechanism).

Question 4

What happens when an animal is castrated regarding testosterone?

Answer 4

Castration dramatically reduces testosterone levels, affecting behaviour.

Question 5

What is the “winner effect”?

Answer 5

Winning a fight increases testosterone, which increases the likelihood of winning future fights, creating a feedback loop.

Question 6

How can testosterone predict social rank?

Answer 6

Higher testosterone levels often predict a male’s future dominance or rank in social groups.

Question 7

How do environmental factors influence hormones?

Answer 7

Factors like temperature and day length stimulate hormone release, triggering behaviours like migration, breeding, moulting, and competition.

Question 8

Which hormones control moulting in birds?

Answer 8

Gonadotropin and thyroxine; thyroxine stimulates feather follicle growth, triggered by daylight cycles.

Question 9

What are sensory neurons and what do they do?

Answer 9

Neurons activated by environmental sensory inputs (chemical or physical), sending information to the brain or spinal cord.

Question 10

What is the pathway of nerve impulses in sensory neurons?

Answer 10

Impulses created at dendrites → travel down axon → pass synapse → transmitted to next neuron by neurotransmitters.

Question 11

Name the main sensory types animals use

Answer 11

Chemical (taste, smell), mechanical (touch, pressure, vibration, sound), electromagnetic (sight).

Question 12

How do insects detect chemical cues?

Answer 12

Sensory neurons on sensory hairs located on proboscis, legs, feet, and antennae.

Question 13

Which vertebrates have the highest to lowest olfactory sensitivity?

Answer 13

ammals > birds > reptiles > amphibians.

Question 14

What is the olfactory bulb?

Answer 14

A part of the brain responsible for processing smell information.