Lesson 2.1 Flashcards
What is a population ?
A group of individuals of the same species in the same area at the same time.
What occurs in populations?
Life processes ,such as reproduction and interactions, take place in populations.
How do the individuals in a population live ?
They rely on the same resources and interact through activities like interbreeding.
What factors can affect a population?
Abiotic, Biotic, and Intrinsic factors
Describe the factors that affect populations.
Abiotic (non-living) factors include sunlight, temperature, soil, and nutrients. Biotic (living) factors include predators, prey, competitors, parasites, and diseases. Intrinsic factors are the adaptations that change a population.
Why is population ecology important?
Population ecology is important so that we understand the factors that influence populations and learn to manage populations to help endangered species and rid of invasive species.
Give an example of how we maintain populations.
An example of maintaining populations is through fisheries which sustain and protect domestic seafood supply.
What are the population metrics?
Size, Density, Population Range, Pattern of Spacing
What are the main ways to count a population?
Direct Count , Indirect Count , Random Sampling, Mark and Recapture
Explain Direct counting
Direct counting counts every individual in a species so it is extremely precise. It isn’t the usual way of counting populations because it is time consuming and financially problematic.
Explain Indirect counting
Indirect Counting is counting by things like hives, towns, nests, etc. It is less consuming than direct counting.
Explain Random sampling
Random Sampling assumes that the population density of a sample is the same as the population density of the total area.
Explain Mark and Recapture
Mark and Recapture is the ratio of marked individuals to total organisms.
What is the formula for random sampling?
of organisms in sample/ area of sample = total #of organisms/total area
What is the formula for mark and recapture?
total marked/total organisms = #marked in recapture/ recaptured organisms
What does direct counting use?
Direct count uses direct proportions to calculate the size of a population.
To get more accurate results in Mark and recapture you would generally do ___ trails and attempt to capture ___ organisms per capture?
(more , more)
In what situations would random sampling work best for estimating populations size?
Random sampling works best in situations where the populations is large and evenly distributed and uniform.
In what situations would mark and recapture work best for estimating populations size?
Mark and recapture works best in situations where the organisms can be captured, released, and recaptured without harm.
What could affect the accuracy of random sampling ?
The size of your samples could affect the accuracy of random sampling because you have to find the right amount to sample or else you might overestimate or underestimate your population size.
What is distribution/dispersion?
The spatial relationship between members of a population within a habitat.
What are the three types of populations distribution?
Uniform - individuals are spaced apart equally
Clumped - individuals are grouped together
Random - individuals are spaced at unpredictable distances
Give examples of uniform, random, and clumped distribution.
Uniform - territorial birds and trees in a plantation
Random - How dandelions grow in a field
Clumped - Elephants at a water hole
Why do populations follow uniform, random, and clumped patterns?
Uniform - resources are scarce and there is competition
Random - equal access to resources and little to no competition
Clumped - common resources, protection from predators
