Interactions Between Organisms and their Environment

Question 1

Ecological Niche

Answer 1

Ecological Niche: the role an organism fulfils in an ecosystem, e.g. its habitat,
nutrition, interactions with other organisms

The interaction between organisms may occur between the same species or
different species within the niche and takes into account changes in behaviour
during different times of the day and different seasonal times.

Question 2

Competition

Answer 2

Organisms in a similar niche within an ecosystem compete with
one another when they use the same resources that are in short supply.

Question 3

Interspecific competition

Answer 3

Interspecific competition refers to the competition for the same resource,
such as a specific food source, between members of a different species. An
example is a kangaroo and sheep competing for grass as their major food
source.

Question 4

Intraspecific competition

Answer 4

Intraspecific competition refers to the competition that occurs between the
members of the same species, such as male brolgas (Australian cranes)
competing with one another to find a mate.

Question 5

Symbiotic Relationships

Answer 5

When individuals from two different species share a close and long-term
biological relationship, it is known as a symbiotic relationship.

Question 6

Mutualism

Answer 6

Mutualism is a symbiotic relationship that occurs when both species within the
relationship benefit from living closely together and neither are harmed.

For example, plants have a mutualistic relationship with pollinators.

Question 7

Commensalism

Answer 7

Commensalism is a symbiotic relationship in which one organism benefits,
while the other organism is not affected (neither harmed nor benefits).

One example is that of a clown fish as seen in Finding Nemo that lives amongst
stinging sea anemones in the Great Barrier Reef. The clown fish in this example
typically uses the stinging sea anemone to hide in not for food but rather for
survival: to protect it from predators.

Question 8

Parasitism

Answer 8

Parasitism is a symbiotic relationship in which one species benefits and the
other is harmed. The species that benefits is called the parasite and the one
that is harmed is the host. The host is often harmed, but not usually killed, as
then the parasite would die too! Instead, the parasite survives on or in the host,
and causes minor damage such as stealing nutrients.

Example - Leech on skin of an animal.

Question 9

Predator - Prey

Answer 9

A predator-prey relationship occurs when one
organism, known as the predator, kills and eats
another organism, known as the prey. It is
unusual for predators to depend upon one species
of prey, so that if the prey species reduces in supply,
the predator can turn to other species to prey upon.

For example, foxes prey on rabbits, but are also
capable of hunting and eating newborn lambs and
other small mammals.