Ecology! Flashcards
Define population ecology
The study of factors affecting the size of a population and how it changes over time.
What patterns for the stability of populations can emerge - name three
- Reaching a stable size and staying there 2. Fluctuating regularly 3. Rising and falling in regular cycles.
Define population
A group of individuals of a single species living in the same general area.
True or false: Populations cannot be defined by physical boundaries.
False - e.g. islands.
Name the two types of competition and describe them.
INTRAspecific competition - members of the SAME species competing. INTERspecific competition - members of DIFFERENT species competing.
Name the three important population concepts
1.Populations have structure 2. Populations are regulated 3. Populations are dynamic over time.
How do birth and death affect populations?
Births add members to a population and death removes them.
Describe Type 1 organisms in terms of their mortality patterns. Give an example.
They have their highest mortality rates in the older population. Tend to be species with a long life span who live in stable environments. E.g. primates.
Describe Type 2 organisms in terms of their mortality patterns.
They have a constant mortality rate throughout the stages of life. Tend to be species who live for a medium amount of time who live in relatively stable environments. E.g squirrels.
Describe Type 3 organisms in terms of their mortality patterns.
Have their highest mortality rates in juveniles. Tend to be species who live for short lengths of time in unpredictable environments. E.g many fish.
True or false: A species can only show one type of survivorship.
False - animals can show multiple types of survivorship throughout different life stages.
name three types of spatial organisations a species can show
Random, uniform and clumped.
When does random dispersion occur?
In the absence of strong competition or a constant distribution of key necessary factors.
Give two examples of uniform dispersion.
Planted crops, territorial animals.
When would clumped dispersion occur?
When there are certain areas of high resource availability, mating behaviours need to occur, the presence of strong predators.
When would you see exponential growth of a population?
When ideal conditions allow for all individuals to have an abundance of critical resources and reproduce at physiological capacity
Describe the Logistic Growth Model
The per capita rate of a population growth approaches zero (meaning the the population size is at capacity.
When would conservation biologists use the logistic growth model?
When predicting the rate of recovery for small populations and when estimating the critical size below which a population is at risk of extinction.
name two density dependent factors
Competition for resources, territoriality, disease, toxic waste etc
Name a density independent factor
Extreme weather conditions.
Define Ecosystem services
The processes by which natural ecosystems help sustain human life
Why is genetic diversity important?
Larger genetic diversity increases the fitness of offspring and therefore allows more to survive/ have the ability to reproduce.
True or false: Species richness does not alter by varying altitude.
False - Species at very low or high altitude are less abundant.
What are the four major threats to biodiversity?
Habitat loss, overharvesting, introduced species, and global change.
Define invasive species.
Animals, plants and other organisms which have been introduced to areas they are not normally found. They have negative effects on that new environment.