2.2 Study Guide Flashcards
How is population growth affected by birth?
Birth affects the population by increasing the population growth. The more individuals that are born, the greater the population size. The number of births is used to help calculate the maximum per capita rate of growth, or r.
How is population growth affected by death?
Death affect a population by decreasing the population growth. If individuals die, then the population size decreases. Death also influences the population growth rate because if there are less individuals to reproduce offspring, then the population growth rate will be less. The number of deaths is used to help calculate the maximum per capita rate of growth, or r.
How do immigration and emigration affect population growth?
Immigration: Immigration affects population growth by increasing it. If more individuals come to an area, then the population size increases. If there are more individuals there to produce offspring, then the population growth will increase.
Emigration: Emigration affects population growth by decreasing it. If individuals leave an area, then the population size decreases. If there are fewer individuals that can reproduce, then the population growth will decrease.
How to sketch an Exponential Growth curve?
An exponential curve is constantly increasing. To draw it, you must draw an upward facing half-U-shape. The curve generally starts as a small increase but becomes steeper as the x and y values increase.
How to sketch a Logistic Growth curve?
A logistic growth curve increases and then decreases. Both variables are increasing to start, and then the y-value slows down while the x-value continues to increase. This results in an S-shaped line.
Where is population growth the highest in exponential growth?
The population growth for exponential growth gets larger as the population size increases. So the highest growth is found at the largest population size.
Where is population growth the highest in logistic growth?
The population growth for logistic growth is the highest at the half way point to the carrying capacity. So the highest exponential growth equals 1/2 the carrying capacity.
What are the variables in growth models and what do they stand for?
N- Population size
N0-Initial Population size
r-maximum per capita growth rate
t-time
K-carrying capacity
dN/dt-Population growth rate (change in #/ change in time)
What are density-dependent limiting factors?
Factors that are dependent on the density of a population. Biotic factors.
Ex: Intraspecific competition, interspecific predation, disease and parasites, social behavior
What are density-independent limiting factors?
Factors that are not related to the density of a population. Abiotic factors.
Ex: Sunlight, water, temperature, natural disasters
How do exponential growth models change when r, N, or K change? Why?
When r increases, the graph becomes steeper and the population grows more quickly. It is the opposite when r decreases.
When N increases, the population will grow larger, faster because more individuals can reproduce.
When K changes, the population growth slows down or speeds up because it has less space and resources to use.
How do logistic growth models change when r, N, or K change?
When r increases the population growth increases faster. When N changes, the population gets to the carry capacity faster. When K changes, the graph becomes less steep because the population has more room to grow.
