A6: Ethology

Ethology

Ethology is the study of animal behaviour (actions and habits) in natural conditions.

Animals are adapted to their natural environment and may act differently when removed so it always best to observe them here.

NATURAL SELECTION

This is the gradual, non random process in which biological traits become more common in a population or less common in a population due to how they influence the survival of that organism.

Natural Selection All organisms want to reproduce and pass their

genes on to the next generation.

If a biological trait gives an organism a better chance to survive, then that organism will likely survive long enough to reproduce and pass on the trait to the next generation.

If the biological trait does NOT give the organism a better chance to survive, then it is likely the organism will die before reproducing and passing the trait to the next generation.

Natural Selection

The trait may be an innate behaviour (one that is preprogrammed and in the genes of the animal)

Ex: Hedgehogs

Hedgehog

Stop here.

Ex: European Blackcap

Summer: Live and breed in Germany

Winter: migrate to Mediterranean (Spain)

European Blackcap

MIGRATION

90% to Mediterranean

10% to UK

European Blackcap

Question #1: Is this direction of travel genetic? (Are the birds preprogrammed to migrate in a certain direction or are they just following their parents? Innate Behaviour Learned?)

European Blackcap

Eggs from both UK birds and the Spain birds were collected

The young birds were reared (away from their parents)

They were released during migration time and the direction of migration was recorded

SPAIN BIRDS: No matter where they were raised, they flew south-west

UK BIRDS: No matter where they were raised, they flew west.

Therefore, it appears that the direction of migration is genetic!

European Blackcap

Question #2: Why would Blackcaps recently start migrating to UK instead of the tradition south-west direction of the Mediterranean? Is there an advantage to this?

European Blackcap

Due to climate change (and global warming), UK winters are not as cold or harsh as before.

Until recently, if a blackcap had a gene which led them to migrating in the UK, those blackcaps would likely not survive the harsh UK winter, and thus not pass on the gene to the next generation

European Blackcap But since now UK winters are more tolerable, if

a blackcap migrates to the UK, they will be able to survive the winter and reproduce in the following spring, and pass this trait on to the next generation.

Furthermore, since few blackcaps migrate to the UK, there will be less competition for food for these birds and thus may be overall healthier.

So the gene for migrating west continues to exist in the population.