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Biodiversity

In this worksheet, students will learn about the importance of biodiversity and how the balance of organism interdependence can be disturbed by human activities and environmental changes.

'Biodiversity' worksheet

Key stage:  KS 3

Curriculum topic:  Biology: Interactions and Interdependencies

Curriculum subtopic:  Relationships in an Ecosystem

Difficulty level:  

Worksheet Overview

QUESTION 1 of 10

The image below shows a recreation of two birds called DODOS.  The dodo used to live on the island of Mauritius in the Indian Ocean.  It is now extinct. This means that there are no dodos alive any more.

 

Dodo birds

 

The dodo was discovered in the early 1500s by European sailors. It was not afraid of humans, as the dodo was not used to seeing them, so it was easily hunted for meat. It was not able to escape since it couldn't fly, so the dodo became extinct in the 1700s.  The introduction of a top predator in the dodo's ecosystem (humans!) led to its extinction.  Additionally, the dodo's habitat was destroyed for crops and the animals the sailors brought with them (e.g. rats and cats) ate the dodo's eggs. 

 

Ecosystems and Biodiversity

 

Organisms in an ecosystem depend on each other.

 

In our example below: if the grass dies out due to drought, the organisms that feed on it (for example mice) will starve and some of them will die so their population will decrease. This will affect the secondary consumers that feed on them (for example snakes) as they will not be able to find as much food.  If new animals are introduced to the ecosystem, this will also affect the feeding relationships and the populations of different species.

 

 

Food web

 

Apart from living organisms, there are also environmental factors that can affect populations.

 

Temperature and the availability of water and sunlight are some very important factors. If the temperature suddenly drops, some organisms may die as they are not adapted to the cold, leading to a decrease in their population. Other animals may need to migrate to more suitable environments in order to survive. Finally, a disease outbreak may wipe out whole populations, too.

 

It has now become clear that every single living organism plays a key role in its ecosystem and the extinction of an organism can have devastating effects on the environment. Therefore, it is really important to maintain biodiversity: a measure of the variety of different types of life on Earth.

 

In other words, a measure of the variety of different organisms present in different ecosystems. 'Biodiversity' could refer to:

 

- different species

- differences between similar species

- even differences between members of the same species.

 

The last is especially significant, when it comes to sudden changes in the environment.  It is important that some members of a species can quickly adapt to the sudden change in order to survive.

 

Human activities are responsible for the population reduction of many species.  Overfishing has caused many fish species to become endangered. A species is endangered when only a few of its members remain alive. There are many endangered species around the world. For example, the white rhino: currently only two white rhinos are alive, both of them female.  White rhinos and other species have been hunted by poachers for their horns.

 

Pollution of the environment and climate change have all played a part in disturbing the balance of ecosystems around the world.

The dodo used to live on the island of Mauritius in the Indian Ocean. It is now extinct.

 

What does this mean?

There are plenty of dodos living worldwide.

There are only a few dodos living in the world.

There are no more dodos alive in any part of the world.

Tick three reasons why the dodos became extinct.

Dodos found new types of food when European sailors settled in Mauritius and ate too much of their foods.

Dodos were hunted for meat by humans.

Dodos could not fly so could not escape humans when hunted.

New species introduced by European sailors, like cats and rats, ate the dodo eggs.

The dodo interbred with new bird species and went extinct.

Why was the dodo not afraid of humans?

Dodos did not evolve to be afraid of humans, because there used to be no humans on the island of Mauritius before Europeans settled in.

Humans did not look scary.

Dodos could fight humans so they were not scared of them.

Use this food web to answer the next few questions:

 

 

What will be the consequences of the population of lions decreasing, say because of an infection?

 

Tick two answers.

The population of jackals will increase.

The population of jackals will decrease.

The population of mice will increase.

The population of mice will decrease.

What will be the consequences to the population of kites if green plants in the ecosystem die out because of drought?

 

The population of kites will increase.

The population of kites will decrease.

The population of kites will stay the same.

What could kites do in order to keep their population the same?

 

Tick ONE answer.

 

Kites could migrate to another place to find food.

Kites could adapt to eating something else in order to survive.

Kites could grow their own food.

Kites could hibernate.

What is the word defined below?  Type it into the answer box.

 

'A measure of the variety of different types of life on Earth.'

What is the main reason why many fish species are endangered?

bigger fish eating them

overfishing by humans

a disease outbreak

What reasons can you suggest as to why poachers hunt rhinos and elephants?

for their fat

for their skin

for their horns and tusks

Define the term 'endangered'.

A species is endangered when only a few of its members remain alive.

A species is endangered when none of its members remains alive.

A species is endangered when there there is a decreasing number of its members alive around the world.

  • Question 1

The dodo used to live on the island of Mauritius in the Indian Ocean. It is now extinct.

 

What does this mean?

CORRECT ANSWER
There are no more dodos alive in any part of the world.
EDDIE SAYS
The dodo is extinct; this means that there are no more dodos alive in any part of the world. It is gone forever.
  • Question 2

Tick three reasons why the dodos became extinct.

CORRECT ANSWER
Dodos were hunted for meat by humans.
Dodos could not fly so could not escape humans when hunted.
New species introduced by European sailors, like cats and rats, ate the dodo eggs.
EDDIE SAYS
There were a few reasons why the dodo became extinct:
• Dodos were hunted for meat by humans.
• Dodos could not fly so could not escape humans when hunted.
• New species introduced by European sailors, like cats and rats, ate the dodo eggs.
  • Question 3

Why was the dodo not afraid of humans?

CORRECT ANSWER
Dodos did not evolve to be afraid of humans, because there used to be no humans on the island of Mauritius before Europeans settled in.
EDDIE SAYS
As there were no humans living on the island of Mauritius, dodos did not evolve to be scared of them. That meant they didn't try to escape and so were easy to catch and kill.
  • Question 4

Use this food web to answer the next few questions:

 

 

What will be the consequences of the population of lions decreasing, say because of an infection?

 

Tick two answers.

CORRECT ANSWER
The population of jackals will increase.
The population of mice will decrease.
EDDIE SAYS
If the population of lions decreases, fewer jackals will be eaten, so their population will increase. For the same reason, the population of wild cats will increase; therefore, they will be eating more mice, so the mice population will decrease.
  • Question 5

What will be the consequences to the population of kites if green plants in the ecosystem die out because of drought?

 

CORRECT ANSWER
The population of kites will decrease.
EDDIE SAYS
If most green plants die out, there will not be enough food for mice, so their population will decrease. As a consequence, owls and snakes will not have enough food, so their population will also decrease. Kites will find it hard to feed, so their population will decrease, too. Basically, plants feed the whole web: without them, it cannot survive. Animals will be faced with two choices: die or migrate.
  • Question 6

What could kites do in order to keep their population the same?

 

Tick ONE answer.

 

CORRECT ANSWER
Kites could migrate to another place to find food.
EDDIE SAYS
The only answer from the options above is that kites could migrate to a different area, where there is more food. Without plants, there will not be any other animals they could adapt to eating as there is nothing to feed them either.
  • Question 7

What is the word defined below?  Type it into the answer box.

 

'A measure of the variety of different types of life on Earth.'

CORRECT ANSWER
biodiversity
EDDIE SAYS
Biodiversity: a measure of the variety of different types of life on Earth. In other words, a measure of the variety of different organisms present in different ecosystems. Biodiversity could refer to different species, differences between similar species and even differences between members of the same species.
  • Question 8

What is the main reason why many fish species are endangered?

CORRECT ANSWER
overfishing by humans
EDDIE SAYS
Many fish species are endangered because of overfishing by humans. Sadly this has led to a massive reduction in fish stocks all over the world, a situation which is being worsened by climate change.
  • Question 9

What reasons can you suggest as to why poachers hunt rhinos and elephants?

CORRECT ANSWER
for their horns and tusks
EDDIE SAYS
Rhinos and elephants are hunted by poachers for their horns and tusks. These are extremely valuable in the markets in Asia and poachers are prepared to break the law, take great risks and kill these magnificent animals in order to get rich.
  • Question 10

Define the term 'endangered'.

CORRECT ANSWER
A species is endangered when only a few of its members remain alive.
EDDIE SAYS
A species is endangered when only a few of its members remain alive. Examples of this around the world range from elephants and rhinos through frogs and fish to butterflies, snails and a whole variety of trees and flowering plants.
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