BIOL112 - Ecology (Set 3)

Lectures 21 & 22 - Behaviour

What is behaviour in ecology and why is it important to an organism?

Behaviour is the way an organism acts in a particular situation, it is crucial to an individual’s survival and fitness, and to interactions between species.

What is behaviour driven by?

Selection (genetics) and learning (experience).

What do Tinbergen’s four questions for animal behaviour ask about?

Mechanism, development, function, and evolution.

What categories are Tinbergen’s quetions divided into?

Questions are divided into proximate causes (mechanism and development) and ultimate explanations (function and evolution).

What does Tinbergen’s question about mechanism ask?

“What environmental stimuli or physiological factors are responsible for short-term changes in behaviour?”

What does Tinbergen’s question about development ask? 

How does behaviour change over the lifetime of an indivudal?

What does Tinbergen’s question about function ask?

What is the adaptive significance of a behaviour? (How does it affect survival and reproduction?)

What does Tinbergen’s question about evolution ask?

How has current behaviour been shaped by natural selection?

What is an example of a mechanism question (lizard example)?

“How does the environment and the animal’s nervous system affect basking?”

What is an example of a development question (lizard example)?

“How does basking develop in an individual?”

What is an example of a function question (lizard example)?

“Why do lizards bask?”

What is an example of an evolution question (lizard example)?

“How did basking evolve?”

What kind of behaviour does natural selection favour?

Behaviour that increases the inclusive fitness of individuals.

What is inclusive fitness?

Referring to both an individuals reproductive success, and the success of its relatives with which it shares genes.

What range of stimuli can animals detect?

Light, sound, scent, tactile, electric fields, magnetic fields?

What is a signal (in behavioural context)?

A signal is a stimulus from one animal that causes a change in another animal’s behaviour.

What is communication (in behavioural context)?

The reception of and resopnse to signals.

(Light) what are the two types of photoreceptors that can be found in vertebrate retina?

Rods (don’t distinguish colour) and cones (do distinguish colour);.

(Light) how does the perception of light differ between organisms?

We all see things different (e.g. many birds and insects can see ultraviolent wavelengths, honeybees can even use polarisation to work out the sun’s position on a cloudy day).

(Magnetic fields) how do magnetic fields help homing pigeons?

Brainstem cells inside the inner ear of pigeons can detect the direction, intensity, and polarity of the Earth’s magnetic field, allowing for a sense of direction in low visibility situations.

(Heat) how do vipers, pythons and boa’s detect infrared radiation?

Because of pit organs found on their faces, which contain a specialised membrane for detection. 

(Sound) what are two examples of organisms which can locate prey in complete darkness using sound?

Owls (who’s retina contain mainly rods, with very few cones) and cats.

(Sound) what is an example of an organism’s sound capabilities being matched to their environment?

The transmission of calls from savanna bladder grasshoppers is poor in forests but great in savannas, while the transmission of calls from forest bladder grasshoppers is poor in savannas but great in forests.

(Scent) why is the ability of introduced mammals to detect prey using scent such a problem for New Zealand’s species? 

Because Aotearoa’s endemic species are not properly adapted to survive scent-based hunting.

(Chemical) what happens when a minnow or catfish is injured, in terms of chemical response?

An ‘alarm substance’ in the fish’s skin is dispersed into the water, inducing a fright response among fish in the area.

(Tactile) what is an example of a response to tactile stimuli in spiders?

Some spiders which prey on other spiders deliberately vibrate the web which makes the prey spider think an insect is caught in the web, when the web owner comes over, the other spider eats it.

(Electric fields) how does the electric eel from South America utelise electric fields?

By generating high voltage currents tp help it detect or immobilse prey and deter predators.

What is learning (in terms of animal behaviour)?

The modification of behaviour based on specific experiences, which can range from very simple to very complex.

What are innate behaviours?

Behaviours with a strong genetic component that are largely independent of environmental influences, these do not need to be practiced, but can improve with experience.

(Innate behaviours) what is kinesis?

The undirected movement in response to a stimulus.

(Innate behaviours) what is taxis?

The directed movement towards or away from a stimulus.

What is migration?

The long-range seasonal movement of animals, which is an evolved, adapted response to variation in resource availability.

Is migration innate or learned?

Migration is innate in many species and learned in others.

What are fixed action patters (FAP)?

A sequence of unlearned, innate behaviours that is relatively unchangeable, triggered by an external sensory stimulus known as a sign stimulus.

What is two examples of fixed action patterns (FAP)?

The egg-rolling behaviour of the graylag goose, and the aggressive behavioural response to red undersides in the three-spined stickleback.

What are supernormal stimuli, and what is an example of one?

An exaggerated, unrealistic version of a behaviour that is even more attractive that the real thing, e.g. birds preferring oversized eggs to real eggs.

What is imprinting and how is it distinguished from other types of learning?

A type of behaviour that includes both learned and innate components, distinguished from other learning types by a sensitive period (a limited phase in an animal’s development that is the only time when certain behaviours can be learned).

What is spacial learning?

The process whereby animals learn about their environment to navigate it and find important resources

What is associative learning?

When an animal learns to associate one stimulus with another.

What is social learning?

When an animal’s behaviour is influenced by that of another.

What is animal cognition?

The ability of an animal’s nervous system to percieve, store, process, and use information gathered by sensory recpetors.

What is foraging?

The act of recognising, searching for, capturing, handling, and eating food items.

What is the optimal foraging model?

A model that views foraging behaviour as a compromise between benefits of nutrition and costs of obtaining food (e.g. predation risk and energy expendature (natural selection should favour behaviour that minimises the costs and maximised the benefits).