Assignment 2
Unique Number: 606178
Due Date: 2020/08/28
Answer all questions.
QUESTION 1 [15]
Define the following concepts and provide examples.
1.1 The Lotka-Volterra model (3)
>> Commonly used model in ecology to describe dynamics between populations – either
from a predator-prey perspective, or interspecific competition. It takes the form a logistic
equation, in each application consisting of two equations (one for each of the populations /
species).
Where N = numbers of a species; K = carrying capacity and r = intrinsic rate of increase
Multiple examples accepted.
1.2 Gause’s competitive exclusion principle (3)
>> Principle that can be stated as follows:
a) If two competing species coexist in a stable environment, then they do so as a result of
niche differentiation, i.e. differentiation of their realized niches.
b) If, however, there is no such differentiation, or if it is precluded by the habitat, then one
competing species will eliminate or exclude the other.
Multiple examples accepted.
1.3 Allee effect (3)
>> Positive relationship between population density and animal fitness that may result in
critical population thresholds. Examples include the passenger pigeon population crash, as
well as other likely thresholds associated with sociality in animals (e.g. wild dogs). Multiple
other examples also accepted.
1.4 Autogenic succession (3)
>> This is succession resulting from biological processes in exposed areas (eg areas that
are exposed by glaciers, lava and so on). Primary succession occurs in these areas. Multiple
examples accepted.
1.5 Biomes (3)
>> A biome is a community of plants and animals that have common characteristics for the
environment they exist in. They can be found over a range of continents. Biomes are distinct
biological communities that have formed in response to a shared physical climate. Multiple
examples accepted.
