BIO205 Lecture 5
- Lecture 5: What is a population?
- Effects show evolutionary changes
o Example of shooting big horn sheep and the decreases in size and weight of the horn in
o Hunters want large individuals with large horns so they shoot them so that as time goes
on, the population of big horn sheep have smaller horns
- So how do the wood frogs do it then?
o They don’t have water in the cell
o Cryoprotectant: Glucose stored in cells
o Encourage ice crystal formation outside of cell
o Control of ice formation outside of cells
o Remain frozen in a period of time where they can freeze certain parts where they want
and not freeze where they don’t want
o They can’t lose too much water too fast though
can’t be below -6 degrees Celsius
not more than 70% body water frozen
temperature drop cannot be too fast
- Penguin picture
o Arctic birds called Northern penguins (they’re not actually penguins though...)
o Adapted to the environment
- What will happen to these birds?
o Immense in huge colonies in the cliffs on the ledges...
o Very small eggs so the hatchlings are small and need to take care of it for a long time
o Sticking the eggs to the rock so that it doesn’t roll?
o Maybe the shape of the egg would make it not roll? Cone shaped egg?
o All birds who build on cliffs have cone shaped eggs
o Polar bears wait at the bottom of the cliffs to wait for eggs or chicks to fall down and
o Global warming might affect these arctic birds because of the fishes that comes into the
water in that region
o We look at the impact on the population and not just on individual bird
- What is a population?
o A population is...
A group of individuals of the same species
Inhabit a given area at the same time
- Populations have a distribution
o The arctic birds are along the Canadian and arctic ridges and Alaskan area
- You can study distributions at various spatial scales
o Starting off in large area and then focus in more, such as regional area o Focus on the bay...but the birds aren’t everywhere...only on high steep cliffs so away