Population Size And Ecosystems Flashcards
What does birth rate mean?
The reproductive capacity of a population
What does death rate mean?
The proportion of individuals dying per unit time
What is immigration?
The movement of individuals into a population of the same species
What is emigration?
The movement of individuals out of a population of the same species
What is the lag phase?
Where there is a slow rate of reproduction because individuals are reaching sexual maturity
What is the log/exponential phase?
Where there is a rapid increase in population numbers as more individuals are available for reproduction.
What is the stationary phase?
Where the birth and death rates are roughly equal, so the population remains roughly the same
What is the death phase?
When the death rate is greater than the birth rate due to environmental factors.
What are some density dependent factors that affect population size?
—Disease and parasitism
—Food availability
—Toxic waste build up
What are some density independent factors affecting population size?
—Floods
—Fires
—Sudden temperature changes
What is intra-specific competition?
Competition between members of the same species
What is inter-specific competition?
Competition between members of different species
Why does the predator population go up when the prey population goes up?
When the prey population increases, there is more food for the predators so their population increases
Why can only one species occupy a particular niche in an ecosystem?
One species will always outcompete the other
What is the study of species abundance called?
Biogeography
What are two ways of counting individuals in an area?
Density, where you count the amount in a number of quadrats and calculate a mean, and percentage cover, where you count the percentage of quadrats with at least one individual in it
How do you sample the change in species over time?
Set up a permanent area in the habitat, and create a 10x10 grid. Generate random coordinates and calculate the percentage cover of species. Return periodically to compare
How would you sample when there is a change in an abiotic factor?
A line along the gradient is measured along, called a transect
What is an ecosystem?
A characteristic community of interdependent species interacting with abiotic components in their habitat.
What is a habitat?
The place where an organism lives
What is a community?
Populations of different species living in the same habitat
What are trophic levels?
Feeding levels within an ecosystem
What is the equation for photosynthetic efficiency?
Photosynthetic efficiency=energy incorporated into photosynthetic products/total light energy falling on the plant X100
Why isn’t all light energy that falls on a plant absorbed by photosynthetic pigments?
-Reflection
-Respiration requirements of photosynthesis
-Need for optimal solar radiation levels
