Module 5 - Ecology

Question 1

What is an ecosystem?

Answer 1

An ecosystem is all the biotic and abiotic components and their interrelationship with one another within a certain area.

Question 2

What is symbiosis? Give an example

Answer 2

Living together of usually two different species with beneficial or negative consequences for at least one of the parties (Commensalism, Mutualism, Parasitism). E. g. Birds using trees for places to construct nests (Commensalism).

Question 3

What is intra- and interspecific competition

Answer 3

Intra-specific competition: within species

Inter-specific competition: between species

Question 4

A group of hyenas killed an old male lion during a fight. How much of the initially energy do they receive when they eat the lion.

Answer 4

In the case the hyaenas are tertiary consumer, because they eat a lion which is a Secondary consumer. On each stage of the trophic pyramid 90% of the energy is used for metabolic activities of the organism.
The hyaenas receive only 0,1% of the initially energy. (Grass 100% -> Impala 10% -> Lion 1% -> Hyaena 0,1%)

Question 5

Explain why parasitism is not the same as predation.

Answer 5

Predation is not parasitism. Usually the predator is larger and/ or stronger than the prey species, the predator is adapted to kill his prey effectively.
Whereas a parasite is usually smaller than the host and may not necessarily kill the host (directly).

Question 6

What is Ecology

Answer 6

The study of interrelationships and interactions between biotic and
abiotic (living and non-living) components.

Question 7

Ecological levels of organisation

Answer 7

1. Individual: a single organism e. g. a single termite, a Marula tree or one lion;
2. Population: a group of organism of the same species which are able to interbreed,
   because they share the same space e. g. all the zebra in a particular Game Reserve;
3. Community: all the populations of a certain area;
4. Ecosystem: all biotic and abiotic components and their interrelationship with another;
5. Biome (ecoregion): broad mappable ecological unit, representing major life zones of
   large natural areas;
6. Biosphere: global system that includes all life on Earth and the physical environments:
   lithosphere (soils and rocks), hydrosphere (water), atmosphere (gases).

Question 8

Functional aspects of an ecosystem

Answer 8

1. Productivity and energy flow
2. Nutrient cycle and Chemical cycle
3. Limiting factors

Question 9

Explain nutrient cycle

Answer 9

1. Primary producers (need water and oxygen)
2. Primary consumer
3. Secondary consumer
4. Tertiary consumer
5. Decomposer => Nutrient pool

Question 10

Explain Trophic Pyramid

Answer 10

1. Primary producers = 100%
2. Primary consumer = 10%
3. Secondary consumer = 1%
4. Tertiary consumer = 0,1%

Question 11

Structural components of ecosystem

Answer 11

1. Abiotic

2. Biotic

Question 12

Keystone species vs Indicator species

Answer 12

Keystone: should the species disappear other species would disappear as well; e. g. Bats;
Indicator species: diversity and numbers of this species indicates the health of an ecosystem; e. g. Frogs.