Lecture 3 - Trade-offs and Density Dependance Flashcards
How can population growth be increased? [3]
Population growth can be increased by:
Increased survival
Increased reproduction
Decreased generation time
How does egg quality vary with clutch number? [2]
Typically, fewer eggs result in healthier eggs.
More eggs result in lighter, more vulnerable eggs.
Why may a larger clutch size be beneficial? [1]
A smaller clutch size reduces the chance of total wipeout due to predation.
Why may a smaller, healthier egg clutch be beneficial? [1]
For harsh conditions, higher quality eggs may be optimal.
What is a Leslie matrix? [1]
A growth rate table that helps measure population growth via lambda (λ)
What’s the most important thing to λ rates? [1]
Adult survival seems to be hte most important feature.
How do you measure change in population size via two time points? [1]
Births during time - deaths during time interval.
What four factors are required for exponential population growth? [4]
A population of few individuals.
In an environment with no limiting factors.
No restriction on available energy.
No restriction on growth or reproduction.
What does the equation dN/dt = bN - dN mean?
Use b = 0.034 and d - 0.016 in a population size of 1000 to calculate this.
[2]
b = birthrate d = death rate N = birth number
dN/dt = Change in population per change in time, which is the same as bN - dN.
bN - d N
(0.034)(1000) - (0.016)(1000)
34 - 16 = 18
So there’s 18+ in population growth in this example.
What does ‘r’ mean in population growth rates? [1]
It’s is the intrinsic rate of increase
What do r values of 0.1, -0.2 and 0 mean? [3]
A r value of 0.1 indicates growth.
A r value of 0 indicates no population change.
A r value below 0 indicates a declining population.
How did sea otters show exponential population growth? [1]
1911 there was a few thousand.
By 1941 there was an increase to 100,000
What’s K? [1]
Carrying Capacity, a limitation.
Populations are pushed towards the ‘equilibrium’ value if they go outside the limits.
