Chapter 2 - Evolution and Behaviour: Natural Selection Flashcards
Why is learning so important? and how do we learn?
learning is important because it allows organisms to adapt to new environments that can easily change
animals adapt to changing environments through experiences
learning happens through experience
What is the driving force of evolution?
the driving force of evolution is reproduction; if one cannot reproduce, then natural selection can’t act on anything
What is the main criteria for evolution?
fitness is the main criteria for evolution
being ‘fit’ means being able to pass genes onto the next generation
What is natural selection?
natural selection involves the increase likelihood of reproduction in individuals with adaptive traits and the representation of those traits in future generations
natural selection is a consequence of being well-adapted
what are the three ways that behaviour can evolve through natural selection?
- there is variation in behaviour
- that variation is linked to a gene and is heritable (passed down)
- That behaviour leads to an adaptive advantage
What is ethology?
The study of the evolution of behaviour
behaviour can not be studied directly from the past so there has to be indirect methods to study it
What are 2 indirect methods of studying behaviour?
1) study behaviours of related species
2) evaluative approach ==> evaluating the possible benefit or survival value of the behaviour; this works best with direct evidence to support hypothesized benefit
What was the Niko Tinbergen experiment w/ black-headed gulls?
Black headed gulls fly distances away with bird shells of their young after a couple of hours after when they are hatched (sometimes within minutes); Tinbergen hypothesized that the bright white lining of the shell would make the nest easier to detect by predators.
Tinbergen did an experiment where he took the shells of the black headed gull and placed them about four inches away from the nest where the eggs were and discovered that the shells were discovered more than the egg itself
Further experiments showed that the farther from an intact egg the eggshell was placed, the safer the intact egg. Tinbergens experiments with black-headed gulls reinforced the idea that eggshell removal improved protection from predators
What are two ways researchers can go about to understand how behaviours have adapted to the environment?
- study related animals in different environments (e.g. black-headed gulls and kittiwakes) where kittiwakes live in high altitudes and have less predators therefore they do not practice the shell removing method
- Study unrelated animals in similar environments and see iff they have the same behaviours (convergent evolution)
What is convergent evolution?
its independant evolution of similar features in species of similar lineages/environments; i.e. flying/wings developing in bats vs. in birds
What are Fixed Action Patterns proposed by Konrad Lorenz?
they are fixed behaviour sequences that are triggered by stimuli called releasers or SIGN STIMULI
these fixed behaviour sequences are highly stereotyped (looks the same every time it happens across organisms)
fixed action patterns do not depend on learning or experience and appear to be innate/genetic
after initial triggering of the fixed action pattern, the sequence will continue regardless of interruptions and does NOT depend on feedback (animal will keep doing this until its done)
Describe the example of three-spines sticklebacks and fixed action patterns
territorial males of the three-spines stickleback attack any type of ‘fish’ that has a red under belly. Even when its replaced with a dummy that doesn’t even look like a fish but has a red belly, they attack. Regardless of whether or not the fish responds
What are two experiments one can do to show that a behaviour is innate?
- Deprivation experiments
2. Artificial Selection experiments
What are deprivation experiments?
removing environmental stimuli and seeing if the behaviour still occurs; its tricky because you can’t remove ALL environmental stimuli
What are artificial selection experiments?
an experiment based off the idea that if a gene linked to a trait has a strong genetic component then the offspring of the animal should also have that trait
What is an example of how innate behaviour can be modified by experience through classical conditioning?
pairing a stimulus with a response
An example of this would be to pair a light before a sickleback is exposed to a red-bottom predator; so US: red-bottom rival UR: attack rival (innate)/aggression CS: light CR: attack rival / aggression
so then sicklback will associate the light with the appearance of the rival and begin to show aggression when exposed to the light
What is an example of how innate behaviour can be modified by experience through operant conditioning?
pairing a behaviour with a biologically relevant response
i.e. Herring-gull chicks will peck at a red dot on the mother’s beak which makes the moms regurgitate food; the more far away from the centre of the red dot they peck at it, the slower they get food; until they learn to peck right on the centre of the red dot
How does habituation occur towards an innate behaviour?
Habitutaion has food implications; people with higher BMI’s habituate to the taste of food slower than people who have lower BMI’s; this means they still get the pleasure of the taste of the food for longer periods of time before they ‘stop tasting it’
Why are innate behaviours beneficial?
beneficial upon first encounter with a stimulus that is dangerous or harmful like a predator
____ allows behaviours to adapt over generations to changing environments
evolution
_____ allows behaviours to adapt over lifespan of an animal to changing environments
learning
How does operant (R-O) conditioning help in adaptation?
R-O –> increases behaviours that increase fitness (i.e. access to food, water, copulations, and increase survival and reproductive success
i.e. parents and babies –> both reinforced by social stimuli such as smiling to get things that need to ‘be fit’
another example is how Crows know the optimal height to feed on whelks
