6.2 Comparing populations

• Biologie
• 9th Grade

6.2 Comparing populations          p. 154

Describe how this affects both populations (in-/decrease) and why.

Red vs. Grey Squirrels

Describe how this affects both populations (in-/decrease) and why.

Milkweed vs. Butterflies

Homework answers (6 - 14)

02:17

Which one is correct?
(decomposers = fungi / bacteria)

1. Primary consumer - producer - secondary consumer - decomposer
2. Producer - primary consumer - secondary consumer - decomposer
3. Decomposer - primary consumer - secondary consumer - producer
4. Producer - decomposer - primary consumer - secondary consumer

02:37

Which one is the producer?

1. the tree
2. the acorns
3. the rat
4. the snake

03:08

Which one is true?

1. A food chain is made from many food webs
2. A food web is made from many food chains

03:19

what does your body
need energy for?

Starter: aquatic food web (1)

In a certain ecosystem we have grass, which grows abundantly in fields and meadows. It uses sunlight to produce its own food through photosynthesis. Another important organism is algae, which thrives in water bodies like ponds, lakes, and oceans, also harnessing sunlight to create energy.

Starter: aquatic food web (2)

We also have grasshoppers, which munch on grass. These insects are crucial herbivores in many terrestrial ecosystems. In aquatic environments, tiny organisms known as zooplankton feed on algae, floating and drifting in the water. Additionally, rabbits hop around the fields, grazing on grass and other plants.

Starter: aquatic food web (3)

Next, we have frogs, which snap up insects like grasshoppers, playing a vital role in controlling their populations. In the aquatic world, small fish feed on zooplankton, acting as a critical link in the food chain. On land, snakes might slither through the grass, preying on grasshoppers and sometimes even small frogs.

Starter: aquatic food web (4)

Finally, we find hawks soaring high and keenly watching for their prey, which includes rabbits, snakes, and small fish. In the water, large fish might hunt small fish, completing the aquatic food web.

SHOW YOUR FOOD WEB!

How many food chains did you see?

The longest food chain:

Workbook page 185

questions 15 a and b

Make a photo and 

upload in the next screen!

Your answers to Q 15 a and b:

Practise questions!

Which animal(s) would be MOST affected if all the grass died?

hawk

sparrow

caterpillar

grass

fox

mouse

berries

Which animal(s) would be
MOST affected if all the grass died?

What would happen to all the hawks if the number of foxes would decrease?

hawk

sparrow

caterpillar

grass

fox

mouse

berries

What would happen to all the hawks
if the number of foxes would decrease?

Mercury in the sea = kwik in de zee

Mercury used to be found in pesticides and paint for boats. Mercury is poisonous and damages the nervous system and reproductive system in mammals.

Look at the food chain and explain why mercury could be a problem for human health.

Explain why mercury could be
a problem for human health.

00:27

What are 'trophic levels?'

1. Food chains
2. Food pyramids
3. Horizontals in a food pyramid
4. Food webs

01:06

What does the width of the bars represent?

1. How much the organisms in it eat
2. How many organisms are in it
3. How much energy the organisms in it have
4. How many organisms are eaten by the next level

01:27

What does each trophic level in a pyramid of biomass represent?

1. How many organisms are in it
2. The combined weight of the organisms in it
3. How heavy the food is that the orhganisms eat
4. How many food items the organisms represent

03:00

What does the width of a trophic level in a pyramid of biomass represent?

Workbook page 187

questions 18 - 22

What you do not finish 

now will be homework.

Q's 23 (2) - 25