Lecture 6 - Interspecific interactions

Question 1

Symbiosis definition.

Answer 1

Living together in a close, often long term ecological relationship between 2 or more species

Question 2

Parasitism definition.

Answer 2

When the parasite benefits however there are costs for the host.

Question 3

Types of benefits gained from mutualism.

Answer 3

• Food for at least
• Protection from enemies
• Provision of favourable
• Provision of ‘service’
  eg. seed dispersal, cleaning

Question 4

What is an endosymbiont?

Answer 4

Provide food, gain nutrients and protection

Question 5

What is an ectosymbiont?

Answer 5

Provide protection or cleaning, gain substrate, transport, protection or food

Question 6

What is obligate mutualism?

Answer 6

Both species depend on one another to survive.

Question 7

What is facultative mutualism?

Answer 7

Positive interaction between 2 or more species rather than an obligate relationship.

Question 8

Mutualism example.

Answer 8

Case study 1: Animal guts and their inhabitants
- Animal gains digestible resources, microbe gains food and stable environment.
Case study 2: Higher plants and fungi - mycorrhizae.
Case study 3: Nitrogen fixation in plants by bacteria.

Question 9

What does exploitation or interference competition result in and what does it lead to?

Answer 9

Results in:
- increased mortality 
- slower development 
- reduced reproduction 
Leads to:
Coexistence or competitive exclusion

Question 10

Interspecific competition example.

Answer 10

Case study 1: Heath bedstraw - grows at acidic sites
Slender bedstraw - grows at calcareous sites
Either will grow on either soil when grown along
When grown together they compete and only one will survive
Case study 2: Red and grey squirrels