5th - Science Unit 5 Lesson 2

Question 0

What do the arrows represent in an food web?

Answer 0

Arrows represent the energy flow from one organism to another.

Question 1

Is the overlapping food chains in an ecosystem; is a network of food chains that have some links in common?

Answer 1

Food Web

Question 2

What does a food web allow you to identify?

Answer 2

Which animals are predators, which are prey, and which are both.

Question 3

Why are different food chains are linked together?

Answer 3

Different predators eat the same prey

Question 4

Give an example of an organism that can be a consumer, an omnivore, a predator and prey.

Answer 4

Fox, rabbit

Question 5

What happens the population of one organism in a food web changes?

Answer 5

All the other populations in the food web can be affected. It affects everything.

Question 6

What happens when top carnivores are removed from a food web?

Answer 6

Prey populations are no longer controlled.

Question 7

What happens when the prey populations increase in number?

Answer 7

They need more producers to supply them with food; would eat more and more producers.

Question 8

Soon the increased populations of prey would be what?

Answer 8

There would be less grass and other producers to support these organisms.

Question 9

This process has occurred in kelp forests by removing what?

Answer 9

By removing just one organism - the sea otter

Question 10

What are kelp?

Answer 10

Giant algae masses the grow more than 30 meters long. Plants.

Question 11

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.

Answer 11

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.

Question 12

Food, water, and other resources in an ecosystem are what?

Answer 12

Restricted

Question 13

Why do organisms compete in the ecosystem?

Answer 13

They struggle or fight for their share of the limited resources.

Question 14

Who competes for these limited resources?

Answer 14

1. Organisms within the population. For example a fox must compete with other foxes to catch rabbits.
2. Populations. For example foxes and hawks because both eat rabbits.

Question 15

What does the survival of a population depend on?

Answer 15

Survival of populations ultimately comes down to resources.

Question 16

What can restrict the size of the populations?

Answer 16

Limiting factors

Question 17

What are the two types of limiting factors?

Answer 17

1. Abiotic - nonliving things

2. Biotic - living things

Question 18

Name some examples of abiotic factors.

Answer 18

Water, temperature, weather, soil type, space to grow, shelter, and sunlight.

Question 19

Name some examples of biotic factors.

Answer 19

Amount of available food

Question 20

Why can many more populations be supported in a forest in the summer?

Answer 20

Because the forest gets more rainfall and is much warmer in the summer than in the winter.

Question 21

Because a prairie ecosystem has more producers than a desert ecosystem, what can the prairie ecosystem do?

Answer 21

A prairie ecosystem can support larger populations.

Question 22

Biotic and abiotic factors determine what for each population?

Answer 22

The carrying capacity

Question 23

What would happen to the deer population if the wolves population increased?

Answer 23

The deer population would decrease.

Question 24

What limits populations?

Answer 24

Overcrowding

Question 25

Explain how algae can lead to overcrowding.

Answer 25

An algae population in a nutrient-rich pond may seem like it could grow indefinitely. But eventually the algae would get so thick that it would start to use up all the available oxygen in the pond. Without enough oxygen for respiration, the algae and other organisms begin to die off.

Question 26

How do populations grow?

Answer 26

When the number of births in that population is higher than the number of deaths.

Question 27

What is the pattern called when a population has access to ample food, living space and other resources?

Answer 27

Exponential Growth

Question 28

Finish this sentence - The larger the population gets, ______________________.

Answer 28

The faster it grows

Question 29

What does a population need to grow quickly?

Answer 29

Access to ample food, living space, and other resources.

Question 30

What population is currently experiencing exponential growth?

Answer 30

Human population

Question 31

What happens to the competition for resources as the population grows?

Answer 31

It increases

Question 32

As population grows, competition for resources increases. How does this lead the birth and death rates?

Answer 32

It leads to the birth and death rates to be equal.

Question 33

What does it mean if the birth and death rates are equal?

Answer 33

That the ecosystem’s carrying capacity has been reached for that species.