5th - Science Unit 5 Lesson 2 Flashcards
What do the arrows represent in an food web?
Arrows represent the energy flow from one organism to another.
Is the overlapping food chains in an ecosystem; is a network of food chains that have some links in common?
Food Web
What does a food web allow you to identify?
Which animals are predators, which are prey, and which are both.
Why are different food chains are linked together?
Different predators eat the same prey
Give an example of an organism that can be a consumer, an omnivore, a predator and prey.
Fox, rabbit
What happens the population of one organism in a food web changes?
All the other populations in the food web can be affected. It affects everything.
What happens when top carnivores are removed from a food web?
Prey populations are no longer controlled.
What happens when the prey populations increase in number?
They need more producers to supply them with food; would eat more and more producers.
Soon the increased populations of prey would be what?
There would be less grass and other producers to support these organisms.
This process has occurred in kelp forests by removing what?
By removing just one organism - the sea otter
What are kelp?
Giant algae masses the grow more than 30 meters long. Plants.
Explain what happened to the kelp forest food chain as a result of removing the sea otter. Include why the sea otter was removed and how that affected other organisms.
In the 1800’s, too many sea otters were hunted for their fur. Without sea otters, fewer sea urchins were eaten. The sea urchin population was soon out of control. Sea urchins destroyed the kelp forests by chewing off the kelp where it was attached to the ocean floor. This caused the kelp to float away. Smaller fish that depended on the kelp could not survive without it, and their populations decreased. The organisms that depended on the small fish began to die off.
Without the sea otter to help control the size of the sea urchin populations, the kelp forests almost disappeared. In the 1900’s, many countries agreed to stop hunting sea otters. However the sea otter population is not recovering as quickly as scientists had hoped.
Food, water, and other resources in an ecosystem are what?
Restricted
Why do organisms compete in the ecosystem?
They struggle or fight for their share of the limited resources.
Who competes for these limited resources?
- Organisms within the population. For example a fox must compete with other foxes to catch rabbits.
- Populations. For example foxes and hawks because both eat rabbits.