7.1 Interactions Between Species

Question 1

List the 6 levels the environment can be studied:

Answer 1

1. Individual level
2. Population level
3. Community level
4. Ecosystem level
5. Biome level
6. The biosphere

Question 2

Describe the individual level the environment can be studied and give some examples:

Answer 2

Single individual species, such as a plant, animal, fungi or unicellular organism.

Question 3

Describe the population level the environment can be studied:

Answer 3

A group of organisms that are the same species living in a certain geographic area.

Question 4

Describe the community level the environment can be studied:

Answer 4

Ecological grouping of different kinds of organisms in a specific place and time that interact with each other.

Question 5

Describe the ecosystem level the environment can be studied and give some examples:

Answer 5

A system formed by organisms interacting with each other and their physical environment.
-Can be simple (such as a dessert), complicated (such as the Great Barrier Reef), or urban (such as a city or town)

Question 6

Describe the biome level the environment can be studied:

Answer 6

A group of communities that have similar structures and habitats extending over a large area.

Question 7

Describe the biosphere level the environment can be studied:

Answer 7

The sum of all ecosystems is the biosphere.

Question 8

What is a habitat? Give 2 examples:

Answer 8

The environment that an organism lives in.
Eg. Flying fox, which is found in tall forest, paperbark swamps, mangroves, and urban areas.
Migratory animals, such as whales which migrate through the year

Question 9

What is a micro-habitat? Give an example:

Answer 9

A small, particular part of a habitat which certain organisms live in and have a slightly different environment to the overall habitat, such as having a lower temperature.
Eg. Beneath the bark of a tree within a forest

Question 10

What is a niche and what does the competitive exclusion principle state?

Answer 10

• The role of an organism/species in an ecosystem (its job).
• The competitive exclusion principle states that no two species can have the same niche in an ecosystem

Question 11

List the 2 types of interactions which species experience:

Answer 11

• Intraspecific competition

- Interspecific competetion

Question 12

What is intraspecific competition? Give an example:

Answer 12

Competition which occurs between two members of the same species.
-Evolution acts at this level
Eg. May be for food, shelter, mates or water

Question 13

What is interspecific competition? Give an example:

Answer 13

Competition which occurs between two different species.
-If different species use the same resource, they will compete for that resource.
Eg. Two carnivores hunting the same food.

Question 14

What is mutualism? List its two types:

Answer 14

Involves an intimate association between two species that offers an advantage to both.

• Obligate
• Facultative

Question 15

What is obligate mutualism? Give an example

Answer 15

When two species completely depend on each other to survive.

Eg. Some plants can only be fertilised by a certain species.

Question 16

What is facultative mutualism? Give an example:

Answer 16

When two species both benefit but don’t rely on each other to survive.
Eg. Ants ‘farm’ aphids and look after them for food (sugar solution) secreted by them, however, neither species depends on the other to survive.

Question 17

What is commenalism? Give an example:

Answer 17

Involves two species which form an association where one organism, the commensal, benefits and the other is neither harmed nor helped.
Eg. A bird forming a nest in a tree, where the tree isn’t harmed by the bird nesting in it, but the bird benefits

Question 18

What is parasitism? Give examples of a why a parasite would do this:

Answer 18

Is a common exploitative relationship in plants and animals, where one organism (parasite) exploits the resources of its host organism (Eg. for food, shelter, warmth)

• The host is harmed but not usually killed
• Parasites can be internal (endoparasites) or external (exoparasites)

Question 19

List 4 ways the host of a parasite could be harmed:

Answer 19

• Reduced life span
• Impaired functions such as digestion or reproduction
• Less ability to withstand stress such as drought or cold
• Greater vulnerability to predators

Question 20

What is a parasitoid?

Answer 20

A parasite which kills its host to benefit itself.

Question 21

What is amensalism? Give an example:

Answer 21

Refers to the association where one species is harmed or killed but the other is unaffected.
Eg. If an elephant steps on an ant

Question 22

What is predation?

Answer 22

Killing living organisms (prey) for food.