YR2-CH18-LSN4

• Biologie
• Middelbare school
• havo, vwo
• Leerjaar 2

LESSON 4

TODAY:

• REFLECTION: LAST WEEK
• PREPARATION: HW FOR TODAY
• LESSON: POPULATION DYNAMICS
• WORKING ON ASSIGNMENTS
• DISCUSSING ASSIGNMENTS

J Curve

- unlimited population growth

- no environmental resistance

- exceeding carrying capacity

S Curve

- limited population growth

- environmental resistance

- stable size around carrying capacity

Give as many examples of abiotic and biotic factors that could be seen as 'environmental resistance'

A rabbit plague

Many years ago a small group of rabbits was released in a large park. Because of low environmental resistance, that group managed to grow exponentially to a population size that exceeds carrying capacity.

In an attempt to reduce the population size, a few buzzards have been introduced into the park. This species of bird of prey will eventually form a population size that does remain stable.

In your notebook:

- Draw a sketch of a graph in which you plot the population size of both the rabbit and the buzzard.

- What do you put at the x-axis, what do you put at the y-axis?

Predator prey dynamics

prey numbers always exceeds predator numbers

Predator tops are always later in time.

Assignments on classroom

first 15 minutes in silence

Assignments on classroom:

"Ecology lesson 4"

ANSWERS

Assignment 1 - R:

_FALSE_ 1. Limiting factors can only be abiotic factors. 

_FALSE_ 2. Immigration is when individuals leave a habitat. 

_TRUE_ 3. Emigration is when individuals leave a habitat.

_FALSE_ 4. A population grows exponentially when it shrinks every generation. 

_FALSE_ 5. They carrying capacity the minimum amount of individuals needed to sustain a population. 

_TRUE_ 6. There is a strong relationship between the numbers of a predator and its prey..

_TRUE_ 7. The size of a habitat is an abiotic limiting factor. 

_FALSE_ 8. A quadrat is used for studying animal populations.

_TRUE_ 9. The human population has grown exponentially since the industrial revolution.

_TRUE_ 10. Animal populations are researched using the capture-mark-release method.

Assignment 2 - T1:

1. The number of animals in an area were researched using the ‘mark, release & recapture’ technique. For this method animals are caught, they are marked with a marker or nail polish and then they are released again. When the scientists return, they again catch animals and pay extra attention to if they catch marked animals again.

a. What factors would the scientist need to pay attention to when marking the animals? Name and explain 2 please.

1. IS THE MARKER OR NAIL POLISH TOXIC

2. WILL THE COLOUR EFFECT THE CAMOUFLAGE

b. Complete the table using the correct formula. 

-20%

Assignment 3 - T2:

1. A class was looking at the different animals found in various areas of the school grounds. Four groups collected samples from three different areas. Then they counted the number of animals in each. 

a. Give a possible guiding question and hypothesis for this research?

- WHICH AREA CONTAINS THE MOST INSECTS?

- IF AN AREA HAS THE MOST NUTRIENTS, THEN THIS WILL CONTAIN THE MOST INSECTS SO I EXPECT THE MOST INSECTS IN THE LEAF LITTER

b. Take each habitat and name & explain 2 biotic and 2 abiotic factors that could influence conditions in these habitats.

TABLE D

c. Looking at Group 3 only, which habitats do ants prefer? 

- SOIL

d. Looking at Group 4 only, which habitats do ants prefer? 

- LEAF LITTER

e. Complete the whole class table below by adding the results of all 4 groups together.

Now use the whole class results from question 3 to answer these questions :

f. Which habitat do ants prefer? 

- LEAF LITTER

g. Why is this answer more reliable?

- BECAUSE IT COMBINES THE DATA OF VARIOUS GROUPS

h. Explain why you wouldn’t use Group 4’s results to make a firm conclusion about which habitat woodlice prefer.

- THERE NUMBERS DIFFER A LOT FROM THE OTHER GROUPS.

Assignment 4 - I:

Some students carried out a study in a local cornfield. They took measurements of the height of the corn plants at a number of fixed distances away from the hedge. They also estimated the biomass of the corn plants. Their result showed that the height and the biomass of the corn plants increased the further away from the hedge that they were growing.

A. Try to explain the student’s results and conclusion.

THE HE MORE SPACE THE PLANT HAS, THE MORE SUNLIGHT IT GETS, MORE SUNLIGHT MEANS MORE PHOTOSYNTHESIS MEANS MORE BIOMASS.

B. The farmer is now considering removing the hedge. Give and explain 2 reasons why the farmer should remove the hedge and two reasons why the farmer should not remove the hedge.

WHY THEY SHOULD REMOVE THE HEDGE:

- CREATE MORE SPACE FOR THE PLANTS WITH SUNLIGHT

- LESS COMPETITION FOR NUTRIENTS AND WATER

WHY THEY SHOULD NOT REMOVE THE HEDGE:

- IT AFFECTS THE ECOSYSTEM OF ANIMALS

- IT ATTRACTS INSECTS NEEDED FOR POLLINATION

HW FOR LESSON 4

WORK THROUGH THE PRESENTATION ON LESSONUP CALLED:

YR2-CH18-HW5