Intro into Evolutionary Behvaiour

Question 1

What is a proximate cause?

Answer 1

It describes CAUSATION - the mechanism of how the behaviour is effectuated
and DEVELOPMENT - the ontogeny of how the organism develops

How they do it

Question 2

What is an ultimate cause?

Answer 2

It descries EVOLUTION - phylogeny of the behaviour and FUNCTION - the selection for the behaviour

Why they do it

Question 3

Niko Tinbergen

Answer 3

Identified these 4 specific questions which can be asked about behaviour

Question 4

Red squirrels and nut stashing

Answer 4

Red squirrels stash their nuts in a single stash underground. They do this in autumn where they are oversaturated with food. They hide these from other animals for survival over winter.
Why does the squirrel stash its nuts:
• Evolutionary history - The ancestors of red squirrels may have collected piles of nuts to eat them away from others and over time these nuts were left as a stash
• Survival value - The selective pressure that maintains this behaviour is that squirrels that better stores nuts better survive winter to breed in the spring.
How do they stash their nuts:
• Mechanisms - Instinct makes them hide the nuts and learning helps them hone their ability

Question 5

Eye spots on moths and butterflies

Answer 5

When harassed by a predator they flash their eyespots to startle the predator long enough to escape.
Why does a moth flash its eye spots:
• Survival value – Behaviour increases the length of survival and so increase the chance it will pass on its genes to the next generation.
• Evolutionary history
How does a moth flash its eye spots:
• Mechanisms – predator stimulates the sensory system that immediately activates the motor system, these two mediated by the hormonal system Progresses over time during development from juvenile to adult. Is therefore controlled by genes and their products, as well as their environmental interactions.

Question 6

Levels of analysis - Proximate Causes

Answer 6

1. Genetic-developmental mechanisms:
   Effects of heredity on behaviour. Development of sensory-motor systems via gene-environment interactions.
2. Sensory-motor mechanisms
   Nervous systems for the detection of environmental stimuli. Skeletal-muscular systems for carrying out responses

Question 7

Levels of analysis - Ultimate Causes

Answer 7

1. Historical pathways leading to a current behavioural trait:
   Events occurring over evolution from the origin of the trait to the present.
2. Selective processes shaping the history of a behavioural trait behaviour in promoting lifetime reproductive success

Question 8

Testing a proximate hypothesis

Answer 8

Orientation in bee wolves - Tinbergen

Is a wasp that provisions her underground nest with honey bees as food. She covers the entrance before going hunting but always finds her way back. She will circle over the nest a few times before she leaves, presumably to memorise the landmarks near the entrance.
Tinbergen tested this by setting up obvious pine cone landmarks around the nest. When the female had left, he moved the landmarks. When the female returned, she went back to the centre of the pinecones – despite the nest no longer being there – supporting the hypothesis.

Question 9

Testing an ultimate hypothesis

Answer 9

Egg shell removal by parent birds - Tinbergen

Parents remove empty egg shells once their young have hatched. He hypothesised that the bright white inside of eggs can attract predators such as crows. This removal therefore increases survival of the chicks by reducing predator visibility of the nests.
He placed eggshells at different distances from the nest. The closer the open eggshells to the nest the more eggs were taken by crows. 42% were taken when the shell was 15cm but only 21% when the shell was 200cm away. This supports the hypothesis that removing hatchling shells increases fitness.

Question 10

Scientific method

Answer 10

1. Ask a question about an observed behaviour.
2. Establish a hypothesis to potentially explain what was seen.
3. Set up predictions based on the hypothesis.
4. Test these predictions by gathering appropriate data.

Question 11

Testing for Evolutionary history

Answer 11

Behavioral questions:

1. Apinae, Bombinae and Meliponinae are eusocial. Show division of labor, co-operative care of young and only a few reproductive members. They cannot live on their own and require a full working unit. The Euglossinae are solitary.
2. The Apinae and Meliponinae are swarming. The nest is overcrowded by spring. The colony raises a new queen and the old queen takes some of the workers in a swarm to find a new nest site. This allows the colony to reproduce via splitting.
3. The Apinae and Meliponinae also transfer nectar between individuals. Forager bees giving nectar to receiver bees that store it in a cell, showing task division.

Question 12

Probable Apidae Phylogeny

Answer 12

Check out tree!
This shows:
• One origin of eusociality – before this point all were solitary and after this point all were eusocial.
• Two origins of swarming – Separately in the Apinae honey bees and Meliponinae (but also could have been a single origin and a loss in the bumble bees)
• Two origins of nectar transfer - Separately in the Apinae honey bees and Meliponinae (but also could have been a single origin and a loss in the bumble bees)
But if the phylogeny is wrong the explanation changes to be less parsimonious: