Chapter 4 Lesson 2
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What does population size describe?
It describes the number of individual organisms present in a given population at a given time.
True or False Population size increases and decrease.
True
How do you determine population size?
Populations size is estimated using sampling techniques.
How does sampling techniques work?
You count the number in a smaller sample area. You then use the information to estimate the number of individuals in the larger overall area.
What does population density describes?
The number of individuals within a population per unit area. (E.g. 1500 golden toads divided by 4 square kilometers =375 toads/square kilometers).
True or False Overcrowded organisms can be more vulnerable to the predators that feed on them, and close contact among individuals can increase the transmission of infectious disease.
True
Describe population distribution.
It describes how organisms are arranged within an area
What are the three population distribution types?
Random Uniform Clumped
What is random distribution?
Individual organisms are arranged within a space in no particular order or pattern.
What is uniform distribution?
A uniform distribution is one in which individual organisms are evenly spaced throughout an area E.g. territories or competition for space
What is clumped distribution
It is where individual organisms arrange themselves according to the availability of the resources they need to survive.
What does age structure describe? Also can be called age distribution
It describes the relative numbers of organisms of each age within a population.
What is an age pyramid/ age structure diagram?
They are visual tools scientists use to show the age structure of populations.
What individuals make up the reproductive group?
Individuals capable of having offspring
True or False Younger and older individuals that haven’t reached the age or have gone over the age of fertility are called post-reproductive
TRUE!!!
Age structure diagrams help predict what?
They can help predict population growth. Populations made up of mostly post-productive age will tend to decline as time goes on. It’s the opposite for populations with pre-reproductive individuals.
What is a population’s sex ratio?
Is its proportion of males to females.
What is sex ratios important for?
It is an important characteristic for populations of individuals.