Population Ecology Flashcards
Define population
a group of individuals of a single species living in the same general area, which are capable of interacting and interbreeding together – generally isolated from other populations
What 3 factors affect population rates
Births
Deaths
Migration
Describe the 3 types of survivorship curves
Type I = convex shape - fairly flat then falls
Type II = Fairly constant slope with individual dying evenly over time
Type III = Drops fast then flattens out
What are k selected species characterised by and give 2 species examples
They only have a few offspring but investing high amounts of parental care
- Humans, elephants, bison
What type of survivorship curves are seen in k selected species?
Type I
What does a Type I survivorship curve tell us about a population?
The death rate in juveniles is low, the individuals usually die in old age
What does a Type II survivorship curve tell us about a population?
Fairly constant threat of death throughout life from disease, predation, parasitism
Which type of species will usually have a Type II survivorship curve?
Rodents
Birds
Invertebrates
What does a Type III survivorship curve tell us about a population?
There is no parental care
Species reproduce abundantly but don’t survive long
Which types of organisms would usually have a Type III survivorship curve
Plants
Marine Invertebrates
Fish
What are r selected species? Give 2 examples of r species
They are species puts that only a small investment of resources into each offspring, but produces many such low effort babies. Such species are also generally not very invested in protecting or rearing these young
- Plants
- marine invertebrates
- fish
Which type of survivorship curve would r selected species have?
Type III
Define dispersion
The pattern of spacing among individuals within an area that the population occupies
What are the 3 types of dispersion?
Uniform
Random
Clumped
Which are the most and least common types of dispersion?
Most common = clumped
Least common = random
