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Component Local example
Genus Camelus
International/Global example
Diceros bicornis
Population Caravan
Community Camels, Sheep, lizards,
scorpions, plants
Sand, rocks
Ecosystem Desert
Rhinoceros, zebra, lion, elephant,,
trees, grass, bacteria
Soil, water, rocks,
Pg. 46:
Food Chain
Interactions between a limited number
of animals in an ecosystem
One path
Food Web
Interactions between most animals in
an ecosystem
Multiple and different paths
Pg. 47:
2. When the number of owl nests becomes high, the abundance of lemmings
increases because as the owl population grows, more owls will be able to feed on
lemmings. In the years that there are zero owl nests, there is also no abundance
of lemmings. This means that the population of lemming is increasing during this
time. The increase of lemming population will result in a negative feedback and
the population of owls increases. Therefore there will be more owl nests and
then an increase in lemming abundance will return. This cycle forms throughout
the years.
Pg. 48:
1. Vegetation -> Herbivorous insects -> spiders -> loads and lizards -> foxes
= 5 organisms
2. Foxes: secondary and tertiary consumer. Spiders: Secondary and tertiary
3. (a) The population of voles will increase due to decrease in predation
from kestrels (b) The population of short-eared owls will increase due to
increase in population in voles.
4. (a) The predators of the rabbits such as stoats and foxes will have an
increase in population due to an increase of supply of rabbit. (b) The
vegetation will heavily consumed by the rabbits and the food supply will
decrease. Which will result to intraspecific competition.
5. The population of the foxes will not be heavily affected due to their ability
to feed on many different animals.
Pg. 52:
1. There are four trophic levels in this food web. Primary Producer, Primary
Consumer, Secondary Consumer, and Tertiary Consumer.
2. The DDT in the body of the cormorant is 6 times more concentrated than
in the water. This happens because the cormorant needs to consumer a
large amount of fish in order to survive. It needs to eat many fish because
the higher in the food web an organism is, the less energy it is able to
produce, and therefore it must eat plentiful fish to get the required
amount of energy it needs to survive.
3. Bioaccumulation occurs in minnows, pickerels, Heron, Osprey, and
4. Bio magnification occurs in all trophic levels
Pg. 53:
a. Pyramid of Numbers
500 Spiders and Insects
b. Pyramid of biomass
10 g Birds
0.25 g of
spiders and insects
4000 Kg Tree
c. The difference in these pyramids is that the size of the tree in the pyramid
of numbers is the smallest, whereas the size of the tree in the pyramid of
biomass is the largest. The same thing goes for the size of insects. Also
what is different about these pyramids is that the pyramid of numbers
shows how many individual species there are and the pyramid of biomass
shows how much matter of the organism there is.
2. The energy “loss” in trophic levels is not in contradiction with the first law of
thermodynamics. The first law of thermodynamics is energy is neither created
nor destroyed, it can only be transferred from one form to another. The energy
that is considered to be “lost” in between the trophic levels is just energy that is
transferred into other forms such as heat. This is what happens when an
organism utilizes its energy and uses it up. That is why the subsequent trophic
level will lose energy because it will not be able to obtain some of the energy that
is transferred by the latter trophic level.
3. The energy available at the tertiary consumer level will be 90 kJ m-2 yr-1 . This
figure is 0.1 % of the energy value at the primary producer level, which is 90,000
kJ m-2 yr-1.