Lecture 1 - Introduction and Foraging

Question 1

What is Ecology?

Answer 1

Ecology is the study of interactions, these can be positive or negative, biotic or abiotic.

Question 2

Define negative biotic interactions

Answer 2

Negative biotic interactions are competitions between species, predation of one species upon another or a parasite taking advantage of an individual.

Question 3

Define positive biotic interactions

Answer 3

Positive biotic interactions are relationships such as individuals cooperating to gather food, engage in sexual intercourse or symbiotic relationships.

Question 4

Define negative abiotic interactions

Answer 4

Negative abiotic interactions could be dramatic environmental events such as tornados, volcanoes, frost, thunder, earthquakes etc.

Question 5

Define positive abiotic interactions

Answer 5

Positive abiotic interactions could be the sun providing an individual warmth. The extraction of nutrients from the soil in order for sustenance or sunlight providing plants the energy for photosynthesis.

Question 6

What are the 8 fundamental ecological principles?

Answer 6

1. Organisms are distributed heterogeneously in space and time.
2. Organisms interact with their biotic and abiotic environments.
3. Variation amongst organisms leads to heterogeneity in ecological patterns and processes.
4. Environmental conditions are not a constant, they are heterogeneous in space and time.
5. The distribution of an organism and their interactions depend on contingencies.
6. Resources are finite and heterogeneous in space and time.
7. Birth and death rates are a consequence of interactions with the abiotic & biotic environment.
8. The ecological properties of species are the result of evolution.

Question 7

What are the two types of obligate (hardwired) variation?

Answer 7

Genetic and developmental variation are hardwired, obligate.

Question 8

What are the two types of facultative variation?

Answer 8

Behaviour and availability are the two types of facultative variation. Facultative means responding to circumstances rather than predetermined nature.

Question 9

What determines individual reproductive success?

Answer 9

Costs and benefits determine an individuals reproductive success, this is termed FITNESS.

Question 10

What term is used to describe an organism which eats a few different types of food?

Answer 10

Oligophagous is an organism who’s feeding lifestyle include a few different types of food.

Question 11

A specialist eats only one type of food. True or false?

Answer 11

TRUE, a specialist is monophagous- only eats one food type.

Question 12

A generalist eats only one type of food. True or false?

Answer 12

FALSE, a generalist is polyphagous- eats many different types of food.

Question 13

What is a search image?

Answer 13

Consumers may develop a ‘search image’ for abundant food (Tinbergen, 1960) and concentrate on their ‘image’ prey to the relative exclusion of non image prey if this food type is abundant. Therefore the inter catch interval will be greatly reduced after the first exposure to the prey.

Question 14

As a predator increases in size what happens to the optimal cost/benefit ratio?

Answer 14

It gets larger.

Question 15

What must be considered when foraging optimally?

Answer 15

Which prey items to take in, which patch to forage in, when to leave a patch and search for another.
selection should favour optimal foragers

Question 16

What are the constraints of foraging?

Answer 16

Foraging time
Minimum energy required
Minimum Na+ required
Stomach capacity

Question 17

What is the marginal value theorem?

Answer 17

It is applicable when resources are patchy
and when depletion reduces food density
MVT is 'when to move on' from a patch
spend more time in good patches
and stay longer in good environments

penguin example with krill