Test 4: Ecology and Ecotoxicology Flashcards
What is a community?
It is a “group” formed when all the different populations of species share the same habitat.
When a group of organisms share an environment.
How do you measure biodiversity?
Species richness and relative abundance.
What is species richness?
It is the total number of species in a community.
What is relative abundance?
It is the number of species in relation to the total organisms in the community.
When is there a high biodiversity?
When the species richness is high and the relative abundance is similar (relatively equal).
What are interspecific interactions?
They are relationships between individuals of different species.
What are the types of interspecific interactions?
- Competition
- Predation (sub-set parasitism(symbiosis))
- Mutualism (symbiosis)
- Commensalism (symbiosis)
What is symbiosis?
It is close and often long-term interactions between 2 or more different biological species.
What is competition?
It is a relationship where different species compete for the same limited food resources.
Which type of species will profit the best from the available resources?
The species that can adapt.
What can strong competition limit?
Strong competition can limit the presence of a species.
What is predation?
It is when one species kills another for food (hunting). The predator feeds on the prey.
What is parasitism?
It is a relationship in which one species benefits while harming another.
What is commensalism?
It is a relationship in which one species benefits without helping or harming the other.
What is mutualism?
It is a relationship in which both species benefit.
What is a population?
It is a group of organisms of the same species living in a shared habitat (defined space) at a given point in time.
What is the population characterized by?
- Size
- Growth
- Density
- Distribution
What is population size?
It is the number of individuals in a population. It can increase, decrease or stay constant over time.
What are factors that affect population size?
- Natality
- Mortality
- Immigration
- Emigration
How do we estimate the size of a population?
- Counting
- Random Sampling (sample area)
- Mark and recapture
How to do to random sampling?
Divide areas of land into equal plots, count the number of individuals in each plot, calculate average, multiply by total area then divide by area per plot.
Average # of individuals / Area per plot = Total population / Total area
How to do mark and recapture?
Capture and mark, release, recapture. # marked in sample 1 (M) / Size of whole population (N) = # marked in sample 2 (r) / Total caught in sample 2 (n)
What is population growth?
It is the increase, decrease or consistency in the growth of a population.
When does the population increase?
When natality + immigration > mortality + emigration