selection pressure

[nooshnoosh95]

i need some help???
we did a prac and it asks for the selection pressure
the prac was looking at a species of flightless birds with different style bills (tweezer, alligator or tong shaped)
our results showed that there is natural selection for the tweezer style birds

can you please state and explain the selection pressure please..i really dont get what selection pressure actually is

thanks in advance for any help

[Jdog]

selection pressure is some factor that affects the existence of a species.

eg. presence of prey, availability of food and water etv.

[nooshnoosh95]

so could it be the shape of the birds bill??

[WhoTookMyUsername]

No. The selection pressure is what environmental factor that selects for different attributes

[BoredSatan]

^+1

so for example in your situation it could be the location of food that the birds eat

[simpak]

The shape of the bill is what the selection pressure selects for, not the selection pressure itself.

[nooshnoosh95]

so it could be any of intra-species competition, food availability and the environment

[WhoTookMyUsername]

No. Have you read what was being said :s intra species comm petition is not the factor of pressure... It's the environment, in this case bill shape

[nooshnoosh95]

wait is the selective pressure the same as the selective agent
if it is then wouldnt it be the ease of picking up the food or the shape of the food (btw the food was grasshopper skeletons)

[nooshnoosh95]

great thanks