Some scientists monitored the population of Cabomba plants in a lake over a period of 6 months. Month January February March April May June Number of plants 765 768 772 483 212 167 Between which months did the number of Cabomba begin to decrease?

Cabomba is an aquatic plant genus, one of two belonging to the family Cabombaceae . Through the data present in the table we can observe that between the month of April to June, the population of the Cabomba plant decreases.

Some scientists monitored the population of Cabomba plants in a lake over a period of 6 months. Month January February March April May June Number of plants 765 768 772 483 212 167 List two possible reasons for the decrease in the population of Cabomba plants.

The two reasons that can affect the population rate of C abomba plants are as follows: Light: The light intensity will produce an increase in the rate of photosynthesis. Cabomba plants require good light and warm water temperatures (from 18-32°C). If enough light does not reach the bottom of the lake then the population of Cabomba plants will decrease. Water quality (dissolve oxygen): For a thriving lake, enough dissolved oxygen should present in the water. Cabomba plant is an aquatic weed, that competes for oxygen with different aquatic animals and plants. If the level of oxygen decrease in the lake and then the population of Cabomba plants will decrease.

E M B I B E

Cambridge Lower Secondary Science Stage 9: Workbook>Chapter 3 - Ecology>Exercise 3>Q 6

MEDIUM

Lower Secondary Stage 9

IMPORTANT

Earn 100

List two causes of extinction of a population.

Important Questions on Ecology

EASY

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Workbook>Chapter 3 - Ecology>Exercise 3>Q 7

Some scientists monitored the population of Cabomba plants in a lake over a period of 6 months.

Month	January	February	March	April	May	June
Number of plants	765	768	772	483	212	167

Between which months did the number of Cabomba begin to decrease?

EASY

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Workbook>Chapter 3 - Ecology>Exercise 3>Q 7

Some scientists monitored the population of Cabomba plants in a lake over a period of 6 months.

Month	January	February	March	April	May	June
Number of plants	765	768	772	483	212	167

List two possible reasons for the decrease in the population of Cabomba plants.

EASY

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Workbook>Chapter 3 - Ecology>Exercise 3>Q 7

The number of Cabomba plants in the lake was estimated by counting the number in one 'sample' area. Suggest one reason why the data may not be accurate.

EASY

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Workbook>Chapter 3 - Ecology>Exercise 4>Q 1

An increase in the human population causes an increase in the demand for electricity.

Name two fossil fuels that are burned to generate electricity.

EASY

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Workbook>Chapter 3 - Ecology>Exercise 5>Q 2

Which of the following is a problem linked to an increase in the burning of fossil fuels:

MEDIUM