Bio Diversity
1Q.
What are the two things the organisms compete for?
Food and Living Place
2Q.
What device is often used to model population growth?
Computers
3Q.
What is the formula for the growth rate?
Growth Rate = Birth Rate – Death Rate
4Q.
What needs to be considered for a more accurate prediction to calculate population growth
rate of any population?
5Q.

Sex ratio of males and females

Number of animals at each age

Migration and immigration
What is the difference between migration and immigration, and how do they affect the
population size?


6Q.
Migration: Movement from one place to another.
Immigration: To move to live permanently.
What evidence is there that elephant is an herbivore?
It is an herbivore because it eats mainly grass and fruits.
7Q.
Produce a simple food web for the elephant and its dung.
Grass
Elephant
Lion
Dung
8Q.
Dung beetles/termites
How is the elephant adapted for:
a)
Obtaining food and water: It sucks up water by it’s trunk
b)
Protecting itself from predators: They live in groups protecting each other.
c)
Avoiding overheating: Take baths in the rivers and lakes and there ears also provide a
large area to protect them.
9Q.
Why have the numbers of elephants increased in the game reserve?
They have stopped killing elephants since 1994.
10Q.
How are the elephants upsetting the balance of the eco system in the Kruger Park?
They eat a lot and have no major predators.
11Q.
Why the Kruger game reserve resorted to culling elephants between 1976 and 1994?
Because they were threatening to destroy the habit for other animals
12Q.
Why was there an outcry against culling? Explain.
It was reducing the number of elephants in the world.
13Q.
When do elephants reach sexual maturity to reproduce, and until when do they reproduce?
They are mature enough to reproduce at the age of 9 and 12 years until they reach the age
of 55-60 years.
14Q.
What do elephants use their tusks for?
To dig up roots, push bushes and trees, dig in river beds and also to defend themselves.
15Q.
What are some of the options to reduce the number of elephants so they do not destroy the
eco system? Write in detail.

Culling: Kill elephants carefully and does not reduce the number of
elephants to the required level.

Relocation: Capture elephants and drug them to sleep and relocate them to
places where they would not harm the environment for other living things.
16Q.
What do dead leaves form on the Woodland floor?
They form leaf litter.
17Q.
18Q.
What is decomposer?
The microbes that carry out most of the decay are known as decomposers.
What are two types of microbe involved in the decay of leaves? Name them.
Fungi and Bacteria
19Q.
Why are toadstools most commonly found in the woodlands in the autumn?
Toadstools like moist weather. If it is wetter and cooler than toadstools are found.
20Q.
Why are so many woodlice found in compost heaps?
They have wet and dry conditions which are ideal for woodlice.
21Q.
What is the process of decay?
Dead leaves are found on the floor and form leaf litter and give home to many animals and
after sometime the leaf litter rots by the help of microbes and dead animals also rot and
decay.
22Q.
Why little decay occurs in a desert? Explain.
Because they have a hot climate while they decay happens in wet and dry climate.
23Q.
Why desert soils have little humus? Explain.
Because they form by decomposing but desert has a hot climate so the don’t have much
decomposing.
24Q.
Why autumn is an ideal season for decaying?
Because it has a dry and wet climate ideal for microbes.
25Q.
Why is compost heaps so important to gardeners?
To recycle garden waste.
26Q.
Why compost heap needs to be turned regularly? Explain.
So all leaves can decompose.
27Q.
Why is decay very important in the recycling of nutrients?
Decay is important for nutrients recycling because leaf litter releases minerals for plants to
use and to do this microbes carry out respiration and produce carbon dioxide, water, and
heat. The dead material forms a material (humus) which mixes with small rock particles to
form soil. Soil rich in humus hold more nutrients for the plants.
28Q.
What is humus and what is it’s relation with soil?
The dead material (broken down leaf litter) forms a material know as humus which mixes
with small particles and forms soil, soil rich in humus hold more water and nutrients for
the plants.
29Q.
What is habitat?
The place where something lives.
30Q.
What are two different ways the owl is adapted to catch mice?

They have amazing hearing.

Catching with the help of their talons.

They adapt to see in the dark.

When they fly they are completely silent.
31Q.
Why does the owl catch several mice?
In order to have enough food they will catch several mice and the mice are too small that
the owl needs more and in order to have a good meal he will eat mice in a large amount.
32Q.
What could happen to the owls if pesticides killed the mice?
The owls will have no food and would decrease the number of owls.
33Q.
Which gas do the microbes need when air is let in as compost heap is turned?
They need oxygen.
34Q.
Why less decay occurs in frosty conditions?
Less decay occurs in frosty conditions because in order for the leaf litter to decay
Wet and dry conditions are needed and the leaf litter would maybe get enough wetness but
does not enough dryness for the leaves to decay.
35Q.
Why are plastic bags not put in compost heap?
Because in a plastic bag the heap will take a lot of time to decay.
36Q.
Which animals survive in the wild?
37Q.
Why is it important that the number of animals of a species does not increase or decrease
rapidly? Explain.
38Q.
It is important for the number of animal not to increase rapidly because the animals
which increase rapidly would not have enough prey for their kind as its not possible that
their prey would also have been growing with the same rate. It is important for the
animals to decrease because they are the prey of some animals and after the decrease
those animals would get no food or less food and won’t be able to survive for long which
would even cause a decrease in their population and then also make the food less of their
predators.
If either increase or decrease would disturb the other animals in a food web or chain and
even break that food chain/web.
Why does the number of rabbits stay fairly constant, even though, they reproduce rapidly?
Give two reasons.



There are too many animals that eat rabbits (many predators),
It does not have a long life spam (9-12 years)
Small animals and insects can eat a rabbit and if even those predators increase
they would not have shortage of food.
39Q.
What shape is the pyramid of numbers for the food chain given below?
Grass → Rabbit → Flea
Fleas
Rabbits
Grass
40Q.
41Q.
Why are there very few foxes in an area of woodland?

They prefer open areas

Like fields

Their prey is not available in a good amount.

They like cooler places
Why was there a rapid increase in the deer population in the Yellowstone Park?
Yellowstone park contained Wolves which were the predator of deers and the population
of wolves were less from before which made the predators of a deer less.
42Q.
What is the dilemma of The Great Barrier Reef in Australia?
The dilemma of The Great Barrier Reef in Australia is that it is made of coral and is eating
up the crown-of-thorns (a type of starfish) which is destroying the animals around it and if
they are removed then there population would decrease and the animals eating it would
not have anything to eat and if they remove the crown- of-thorns and relocate them then
animals present in the Great Barrier Reef would have also decrease the predators
population.
43Q.
How do the lynx control the hare population? Give evidence to support your answer.
The lynx control the hare population by as hare increase they have more food available
and the lynx would increase and they would also have more food so they balance it.
44Q.
What is a pest?
An insect or animal that attacks crops, food, or livestock
45Q.
Why do you get lots of slugs when you grow lettuces?
Slugs come in the category of pesticides and destroy the plants.
46Q.
Why are chemicals used to control pests?
Chemical which control pests are known as pesticides. They kill pests quickly and stop
them from destroying the plants, crops and livestock.
47Q.
What are the chemicals called that are used to control pests?
Pesticides
48Q.
What are some types of chemicals that are used to control pests?
Herbicides for weeds, Insecticides for insects, and Fungicides for fungi.
49Q.
What have humans tried to get rid of pests?
Chemical sprays.
50Q.
What problems have come from the use of pesticides? Give a detailed answer

Other animals were also killed by poisons.

Pesticides build up an environment and lead to many carnivores death breaking
their food chain.

51Q.
Pests become resistant to the pesticides and continue harming the plants etc.
What is the use of natural means to control pests called? Give examples.
Biological Means:

Ladybirds used to control whiteflies from attacking tomato plants in
greenhouses.
52Q.
Name one advantage of using pesticide, and one advantage of using predators.
Pesticides: It quickly kills the pests.
Predators: They don’t harm other animals
53Q.
Name one disadvantage of using pesticide, and one disadvantage of using predators.
Pesticides: It sometimes harms or kills other animals.
Predators: It would take much time for an animal to kill another and clean up the mess
54Q.
55Q.
Why biological control does not always work? Give two examples.

Cane toad was used to control cane beetles but now is a major pest.

Cats were used to control rats but instead they raided dust bins.
What is the benefit of biodegradable pesticides?

Can be cheaper than chemical pesticides.

Can be more effective than chemical pesticides
56Q.
Complete the following table by indicating whether the ant population will grow reduce or
stay the same.
Statements
Grow/Reduce/Same
In spring the queen ant lays lots of eggs as she emerges from
dormancy in the winter. Several of the eggs hatch into worker
ants after 20 days.
Plenty of food is available. The worker ants feed the queen so
more eggs are laid. More worker ants hatch.
In summer, drought conditions occur and little food is available
for the queen to produce eggs. Several workers die.
The heath land catches fire, killing many workers but not the
queen.
Rain allows new growth of plants and plenty of food is available
to feed the queen so she can produce eggs.
The onset of cold in late autumn kills many workers and the
queen prepares to survive the winter in a dormant state.
57Q.
Grow
Grow
Reduce
Reduce
Same
Reduce
Complete the following table by listing the correct pest with the correct garden plant or
animal.
58Q.
Garden Plants
Pests
Roses
Greenfly
Tomato Plants
Whitefly
Lettuce
Slugs
Sheep
Lice
Complete the following table by the stating the different factors and their examples that
affect the size of population.
List of Factors
Examples
Physical Factor
Temperature, Rainfall, Acidity
Catastrophes
Flood, Fire, Drought, Earthquake
Biological Factors
Competition, Predation, Disease/Parasites
State whether the following statements are ‘True’ or ‘False’. If ‘False’, then rewrite the
59Q.
correct statement, and support your statement.
1.
All bacteria cause disease. False : Some
2.
A population is the number of all the animals in an area. True
3.
Some of the most poisonous animals in the world are found in Australia. True
4.
All predators are carnivores, and all preys are herbivores. False: Omnivores
5.
Fungicides are fungi used to kill pests. True
6.
Predation is important to a prey as it allows only the strongest ones to survive. True
7.
Dung beetles are decomposers. True
8.
Compost heap breaks down to form the humus part of soil. True
9.
One of the reasons many worms are found in compost heaps is that they are very moist.
True
10. Energy is lost from a food chain as heat. True
11. Ox pecker warns the ox of the approach of predators. False: eats pests of ox
12. When the heath land catches fire, it kills many ant workers and the queen. False: But the
queen
13. On an average, a female elephant gives birth every five years. True
14. Elephants have major predators. False: Minor
15. The hare population size controls the number of lynx. False: The lynx population controls
the number of hare.
60Q.
Fill in the blanks.
1.
Both Wasps, and Bees have stings but drone does not.
2.
Some of the most poisonous animals in the world are found in the country Australia
3.
The Indian Taipan is the world’s most poisonous snake; one bite contains 110mg of
toxin enough to kill up to 100 people.
4.
The blue-ringed octopus, the funnel web spider, and the box jelly-fish can all be deadly.
5.
Rattle snake lives in desert areas.
6.
Energy is transferred from the sun to planet material by the process of photosynthesis
7.
Another name for a dung beetle is scrab
8.
Non-living factors in the size of population are regarded as a-biotic factors whereas,
biotic factors are living factors.
9.
The elephants and rhinos are part of the big Five animals in Africa.
10. Another name for killing elephants is culling
11.
Culling is essential for elephant survival.
12. The leaf litter is rotted down by microbes
13. Woodlice are the most efficient organisms at breaking down wood.
14. The microbes that carry out most of the decay are fungi and bacteria
15.
16.
Compost heaps are kept by the gardeners to decay garden waste.
,
,
plants and
remains are
and can be put on compost heaps.
17. Kew gardens has one of the biggest compost heaps in the world.
18. The number of organisms of one type (species) in an area is called it’s population
19. The number of
falls followed by a fall in
20. Pests destroy garden plants, trees and feed off animals.