2.1 Study Guide Flashcards
What is the definition of a Population?
A population is a group of individual organisms of the same species living in the same place at the same time.
What is Population Density? How is it different from regular Population?
Population density is the number of organisms in a population per specific unit of area. It differs from population because population is the total number of organisms in an area, while its density is the average number of organisms within every smaller fraction of that area.
What is Population Distribution? How does it relate to Population Density?
Population distribution is the way in which a population is spread throughout its area. It relates to population density because specific patterns of population distribution generally translate to specific ranges of density.
Wolf populations tend to live in large groups known as ‘packs’. What type of population distribution does this show? Why?
This behavior shows Clumped distribution because the wolves live in ‘clumped up’ social groups that are separate from each other.
What is the difference between Random and Uniform population distribution? What are the general causes for each of them?
Random distribution denotes unequal spacing between individuals all throughout a population, while uniform distribution denotes equal spacing all throughout. Random distribution is generally caused by a widespread abundance of resources allowing individuals to live completely independently, while uniform distribution is caused by a widespread scarcity of resources making individuals have to fight for set territories.
Give an example of a population that would usually have uniform distribution.
Possible answers include: Human-made forests, flocks of nesting birds, plants which release toxins in a set radius, etc.
What is one of the main causes of clumped populations?
Clumped populations are usually caused by either social interaction leading to individuals grouping up for protection or a centralized abundance of resources (like a large carcass) attracting a large number of individuals to one location.
In a flower field, the flowers grow in a random population distribution. Explain why this could be the case over the other types of population distribution.
Because random distribution is usually caused by an abundance of resources, the flowers are likely growing in soil that is nutrient rich all around, allowing them to grow in any place without having to fight for resources. This, along with the fact that flowers don’t form social groups or move towards resources, is likely why the flowers aren’t growing in a uniform or clumped distribution.
Scientists are recording the numbers of a reindeer herd within a 15 square-mile area. They count that there is a total of 285 reindeer in the herd. Using this information, what is the population density of the reindeer per square-mile? (show work)
285/15=19, so 285 reindeer/15 square-miles=19 reindeer per square mile. Thus, the density is 19 reindeer/square-mile.
Researchers are trying to find the total population of wild rose bushes in a 500 square-meter area. They split the area into a grid of 10-square-meter quadrats and randomly count the number of rose bushes in seven of them. The numbers are 3, 6, 4, 2, 3, 5, 5. Using this information, estimate the total population of wild rose bushes within the 500 square-meter area. (show work)
3+6+4+2+3+5+5=28. 28 bushes/7 quadrats=4 bushes per quadrat. 500 square-meters/10-square-meter quadrats=50 quadrats. 50 quadrats x 4 bushes per quadrat=200 bushes in total. Thus, there are 200 wild rose bushes in the 500 square-meter area. (could just simplify to x/500=28/70–>70x=14000–>x=200)
To find the total population of wild pigs in an area, a researcher captures 15 pigs, marks them, and lets them go. Later, they capture another 15 pigs and find that only 3 of them are marked. Using this information, estimate the total population of wild pigs in the area. (show work)
x=total. x/15 marked=15 recaptured/3 recaptured with mark–>3x=225–>x=75. Thus, there are 75 wild pigs in total.
For what type of organism would a scientist normally use quadrats to estimate the population of? For what type would the mark and recapture method normally be used? Explain why for both.
Scientists would normally use quadrats to estimate the populations of plant species and the mark and recapture method for animal species. This is because plants are stationary and, thus, easy to observe and record using the stationary quadrats, while animals move around and can be better kept track of by capturing and using marks to record.
A rectangular area in Antarctica that is 500 square-meters by 400 square-meters has a population of 400000 emperor penguins. What is the density of the population? Using this information and your own knowledge of penguin behavior, predict what type of distribution this population has.
500 square-meters x 400 square-meters=200000 square-meters total in the area. 400000 penguins/200000 square-meters=2 penguins per square meter. Thus, the population density is 2 penguins/square-meter. Since emperor penguins are quite large and because they usually stand close to each other in colonies to stay warm, it can be inferred that there is not much space between each penguin all throughout the area. Thus, because all the penguins are likely about equally close to each other, the most probable distribution for this population is the uniform distribution.
