Chapter 6

Basic Definitions
Habitat:
A specific place where a group of
organisms can live and reproduce
is called habitat.
Environment:
The sum of biotic and abiotic
factors around an organism is
called an environment.
Adaptation:
The adjustment of organisms to
the changes in their habitat is
called adaptation.
Competition:
The struggle of organisms either
of the same species or different
species for food, water and space
is called
competition.
Succession:
The replacement of one species of
organisms by another species of
organisms in a particular region is
called succession.
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Questions And Answers
Q1. What is habitat?
Ans: A specific place where a
group of organisms can live and
reproduce is called a habitat.
Examples:
Ponds, streams, lakes, deserts
and forest are some of the
examples of habitat.
*****
Q2. What is the difference
between an organism's habitat
and it's environment?
Ans:
Habitat:
1- A habitat is a specific place
where a group of organisms can
live and reproduce.
2- A habitat is always a preference
of one specie.
3- A habitat always has life in it.

Environment:
1- The sum of biotic and abiotic
factors around an organism is
called an environment.
2- An environment could be a
preference of two or more species.
3- An environment does not
necessarily has life in it.
****
Q3. What is an ecosystem? Give
three
examples of an ecosystem.
Ans:
Ecosystem:
An ecosystem is a biological
community and the physical
environment associated with it.
Examples:
Grasslands, deserts and oceans
are three examples of an
ecosystem.
*****
Q4. What do all animals need to
survive?
Ans: All animals need food, water
and space for survival.
*****
Q5. What does the word "adapted"
mean?If an animal is adapted to
its habitat, what does this mean?
Ans:
Mmeaning of The Word "Adapted":
The word adapted means the
adjustment of organisms to their
environment.
* If an organism is adapted to it's
environment, it means that the
organism will be able to survive
the climatic conditions of that
environment.
*****
Q6. Give an example of how an
animal's environment can change
from one part of a day to another.
Ans: An animal's environment can
change from one part of a day to
another and the animal is adapted
to that change.
Example:
Environment of dessert animals
changes daily. Many dessert
animals hide during the day to
avoid the heat of the sun and
came out at night to feed when it
is cooler and less water
evaporates from their bodies.
*****
Q7. Give an example of how a
plant's environment can change
from season to season?
Ans: A plant's environment can
change from season to season
and the plants are adapted to
those changes.
Example:
When winter begins, the sunlight,
temperature and availability of
food become scarce therefore
deciduous trees shed their leaves
to withstand these changes.
*****
Q8. What limit the number of
species that
can survive in a habitat?
Ans: The number of species that
can live in a habitat is limited by
environmental factors such as
adequate food, water, shelter and
climatic conditions.
*****
Q9. What do some animals do to
survive at difficult seasons of the
year?
Ans: Some animals that live in
difficult seasons of the year have
adaptations that allow them to
survive these seasonal changes.
Some animals migrate, some grow
a thicker coat while some
hibernate in difficult seasons of the
year.
*****
Q10. Most flowers close up at
night for protection, but a few
flowers remain closed until dusk
and then remain open till
morning. Can you suggest
reasons for this?
Ans: Most flowers close up at
night to protect their pollen grains
but a few flowers e.g bat pollinated
flowers remain closed during the
day. They open up at evening to
be pollinated by bats and remain
open till morning.
*****
Q11. What are the two main
groups of decomposers? How do
decomposers obtain their energy?
Ans:
Two Main Groups of
Decomposers:
The two main groups of
decomposers are bacteria and
fungi.
Energy of Decomposers:
Decomposers obtain their energy
by
eating dead plants and animals.
*****
Q12. Explain why life on earth
could not continue if there were no
decomposers?
Ans: If there were no
decomposers on earth then the
earth will be full of dead bodies of
organisms and dead bodies will
pile up everywhere. Decomposers
play a vital role in the flow of
energy in an ecosystem so without
decomposers the life on earth
could not continue.
*****
Q13. What do the arrows in a food
chain or food web represent?
Ans: The arrows in a food chain or
food web represent the flow of
energy from producers to
consumers.
*****
Q14. Why do most food chains
have only two,three or rarely four
consumers after the green plant
producer?
Ans: Most food chains have two,
three or rarely four consumers
after the green plant producer.
This is because so much energy is
lost the surrounding environment
mainly in the form of life processes
such as respiration, excretion and
reproduction.
*****
Q15. What would be the effect on
the plants and animals in a food
chain if
a. The top predator increased in
number
b. The plant producers increased
in number
Ans:
a. If the top predator increased in
number, they will decrease the
size of prey population.
b. If the plant producers increased
in number, they reduce water
clarity and harm water quality.
*****
Q16. A weed killer was sprayed
onto a field of wheat. A few weeks
later it was noticed that a large
number of owls in a nearby wood
were dying. The owls eat only
mice and other small mammals,
they do not eat wheat. Could the
deaths of the owls be caused by
the weed killer? Explain your
answer.
Ans: When a weed killer is
sprayed onto a field of wheat, it
build up in the soil. The weed killer
enters the mice and small
mammals bodies when they feed
on the
insects living there. The mice and
small mammals are then eaten by
the owls and weed killer enters the
owls bodies which leads to their
death.