Year 9 Science – ECOLOGY Revision 2013
NAME: answers by Mr. Hung
1. What is Ecology?
Ecology is the scientific study of interactions of organisms with one another and with the
physical and chemical environment.
2. Organisms living in different habitats need different adaptations. What are adaptations? Give 3
examples of adaptations of living organisms.
The special characteristics that enable plants and animals to be successful in a
particular environment are called adaptations.

Camouflage, as in a toad's ability to blend in with its surroundings.

Some desert plants, such as the barrel cactus, have expandable stems for storing water.

Many are nocturnal, meaning active during the cool night rather than the hot daylight hours.

The kangaroo rat conserves water by excreting a solid urine rather than liquid.

Some plants have a waxy coating on the leaves, or have small leaves, that reduce the surface
area exposed to the drying elements.
3. Give some Human impact on the environment.

Habitat destruction – clearing land to build and grow food removes habitat for native
species.

Introduced species – compete with native species, prey on them or destroy habitat.

Pesticides – can kill beneficial species and may accumulate in food webs.

Overcropping – removing more individuals from the population than can be replaced by
breeding.

Chemical pollution – toxic chemicals that kill species.
4. What are the differences between producers and consumers? Give examples
Producers make their own food by photosynthesis, eg. Green plants such as trees and grass, and
seaweeds (algae)
Consumers are animals that eat others and they can’t make their own food. They can be
herbivore, carnivore and omnivore. Eg. Human, cow, rabbit, eagle, worms
5. Name 3 common types of consumers with respect to the types of food they eat.
They can be herbivore (plant eaters), carnivore (meat eaters) and omnivore (eating both plants
and animals)
6. What is a Food Chain? Give 3 examples of food chain?
A food chain is the sequence of who eats whom in a community.
Grass  Grasshopper  Rat  Snake  Eagle
Seaweed  small fish  large fish  shark
Water plant  mayfly larvae  dragonfly nymph  fish  water bird
7. A special group of organisms : the decomposers, they are very important in the ecosystem.
What are they? What are their roles?
They are decomposers (fungi and bacteria) break down the dead bodies and their urine and
faeces and return the material to the soil and air for reuse by plants.
8. The following diagram shows a flow chart of how energy is transferred in an ecosystem.
Click at the Ecosystem Button  Environmental Biology Sequence - Ecosystem
Label in the space with the following words:
Decomposer, Producers , Sun Energy ,
Consumers
Sun
Energy
Producers
Consumers
Decomposers
9. Name the process by which:
a) Producers make their own food using sun energy. Photosynthesis
b) Consumers obtain energy from food they eat. Respiration
10.
What is the percentages of energy that can be moved along a food chain from one organism
to the next? What happens to the rest of the energy?
Only 10% will be moving along a food chain from one to the other organisms. The rest 90% will be
eventually lost as HEAT
11. Give TWO differences between a food chain and a food web?
FOOD WEBS show how plants and animals are connected in many ways to help them all survive.
FOOD CHAINS follow just one path of energy as animals find food.
A food web shows more realistic representation of the feeding relationship between organisms – an
organism may be eaten by many organisms instead of by one organism in a food chain
12. Symbiosis is the term for any biological relationship between 2 different organisms living in
close association or direct contact with each other. There are 3 main types namely:
MUTUALISM
COMMENALISM
PARASITISM
Find out the meaning of each and give 2 examples of each relationship.
The 3 types of Symbiosis are Commensalism, Parasitism, and Mutualism.
a. Example of Commensalism is a Spanish moss that receives sunlight by the a tree's
help; the tree gets nothing in return;
b. On parasitism, a dog with fleas benefit from the dog's blood as food and the dog gets
harmed.
c. On Mutualism is E. coli bacteria that gets energy from food eaten by a human
producing vitamins that the host uses.
13. Find out some adaptations of : (give an example of physical adaptation and an example of
behavioural adaptation)
a) Shark - Sharp teeth to prey on sea animals eg. Seal
Having camouflage with the rock to hunt for sea animals
a) Rabbit - Long and sensitive ears to hear the surrounding and long muscular legs to run
away from predators; Digging holes in soil to hide from predator
a) Echidna - Protected by long spikes; rolling the body into a ball so that others can’t attack
a) Elephant - Long trunk and teeth to protect the animal; squirting water to wash and cool
the body – Large ears to cool down the body.
14. What are required for Photosynthesis to take place? Use a chemical equation to represent
this process.
15. How is cell respiration different from breathing?
Breathing is the taking in oxygen and giving out carbon dioxide by the respiratory system
(lungs or gills) – It is a mechanical process. On the other hand, Respiration is the release of
energy by breaking down glucose (sugar) with oxygen. Carbon dioxide and water are the byproducts (=metabolic wastes)
16. There are two types of Respiration – aerobic and anaerobic respiration. Give the differences
between them.
Aerobic
Respiration
Anaerobic
(in yeast and plants)
Anaerobic
(in muscle)
Oxygen is required Yes
or NOT
No
No
Starting material
Glucose
Glucose
Glucose
By- product(s)
number
They are …….
2
carbon dioxide +
water
2
carbon dioxide + ethanol
1
lactic acid
17. Label the structure of the leaf and write down the function of each structure.
palisade mesophyll layer, stoma, xylem, upper epidermis, lower epidermis, phloem, air
space, chloroplast, guard cell, cuticle, vascular bundle/tissue, spongy mesophyll layer
A= Cuticle
B= Upper epidermis
C = guard cells
D = Palisade cells
E = Vascular
bundle/tissues
F = Spongy Mesophyll
B = Lower epidermis
1. Build a Food Web:
Snake, Grass, Eagle, Gum tree, caterpillar, ladybird, ant, rat, aphids, grasshopper, Bee
Add a few more if you like…..
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