chapter 5 Flashcards
Canada’s cod population is an example of….. growth
Logistic: the growth rate decreases as the population reaches carrying capacity
What is population ecology?
- the study of population dynamics of species and how populations interact with the environment.
- They question things like…
*how fast pops grow
*limiting factors
*# organisms in equilibrium
What is exponential growth?
Exponential growth happens when you start with small populations
- It describes populations under ideal unregulated conditions
- more creatures are born than die (ex. grey seal pop in sable island)
- Not sustainable (resources become lilted competition increases-growth unsustainable)
- Maximum growth varies between species
What is logistic pop growth?
- when a population stops growing exponentially
- birth rates slow death rate rises
- carrying capacity (k) max sustainable pop size in an environment
- When pop size (N) =k pop is in equilibrium
- when n<k growth is exponential
- pop slowed by limiting factors
Population- growth and harvest time
- pop collapse occurs when harvest exceeds pop growth
- Maximum sustainable yield is the largest sustainable harvest (it’s at about half of carrying capacity
Fecundity
- Is the number of offspring produced by an individual per season
- birth rate may be age specific
- determined growth is when fecundity is consistent (doesn’t matter age - either way, same # of kids)
- Indeterminate growth-fecundity increases with age until senescence
Iteroparius vs semelparous
Bred once vs many times
Who is Semel
Virgin priest
zeuse has sex with her once, then she died
What are the three types of survivorship curves?
Type 1 (human): low mortality except in old age
Type two (mouse): constant rate of mortality
Type 3 (salmon): high mortality as babies progressively less
When a creature has determined growth (they stop growing at a certain age) they typically have the same number of offspring
When a creature has undetermined growth (they grow bigger as they get older) they have more kids as they age
Life table
Look @ slides
Exploitation competion
Competition for resources without direct interaction
ex. moose eats all plants = less herbivour snacks
Interference competition
Direct interaction
action to reduce access to a ressource to others (fight)
What is Lotka-Volterra competition model
If two species are competing for one resource, their growth is influenced by each other and their competitive ability
What is the formula for open population
Nt+1 =Nt + (Mt - Dt) + (It - Et)
E=emigrants
I=imagrants
N= # individuals
M= births
D=deaths
t= time
What is the formula for a closed pop
N= M-D
