19.4 Predation Flashcards
What is a predator
What is prey
A predator is an organism that feeds on another, known as their prey
So predator and prey have evolved alongside each other
If either of them had not matched the adaptations of the other, it would have become extinct
What are some characteristics that predators have adapted to hunt their prey better
. More effective camouflage
. Faster movement
. Better means of detecting prey
What are some characteristics that prey have adapted to avoid predators
Better camouflage
More protective features eg spines
Concealment behaviour
If in a lab, a predator and prey are put together, the predator will eat the prey
How is this different to in nature, showing why prey rarely become extinct
The range and variety of the habitat is confined to the lab
So in nature the situation is different:
. The area the prey can travel is much further, and variety of environment is more diverse
. Eg there are lots of refuges so prey can escape predators
This is why prey rarely become extinct
Describe the effect of predator prey relationships on population size
. Predators eat their prey, so reduce population size of prey
. So there is less food available for the predators, so they are at greater competition with each other for the few prey left
. SO predator population decreases as some individuals can’t find enough prey so can’t survive and reproduce
. So few predators means few prey are eaten, so more survive and can reproduce
. So prey population increases
. So with more available food, predator population increases
Why is the predator prey relationship not always accurate in nature
In natural ecosystems, organisms eat a range of foods and therefore the range in population sizes are less severe
What are other reasons for fluctuations in population size
Why are population crashes important
Disease and climatic factors play a part
These periodic population crashes are important in evolution as there is a selection pressure which means those individuals cant escape predators as well, withstand disease, or an adverse climate
So will reproduce less so population evolves
