Chapter 11 Population Distributions Ecology: The Economy of Nature Flashcards Preview

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Flashcards in Chapter 11 Population Distributions Ecology: The Economy of Nature Deck (48)
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A species' _____ is the range of abiotic and biotic conditions under which it lives.

realized niche


The lifetime dispersal distance is most useful for predicting _____.

how fast a population will increase its geographic range`


An isolated patch of individuals within a greater set of populations is called a(n) _____.



The concept of a species' ecological envelope is similar to its realized niche, except that an ecological envelope describes _____, whereas a realized niche describes _____.

where a species could live; where a species does live


The Christmas bird count is conducted every December by volunteers who spend a day following a predetermined path that covers a 24-km circle and counting the number of different bird species they see or hear within the circle. The Christmas bird count is considered a(n) _____ survey.



In a population that occupies multiple habitat patches, why shouldn't all individuals try to move to and live only in the habitat patch that has the highest-quality resources?

Per capita resource availability would be very low.


The abundance of a population generally increases as its _____.

geographic range increases


True or false? Among scientists, there is a general consensus that resource distribution should cause a species' abundance to decrease as its geographic range increases.



A nonmigratory male bird hatches in a nest in New Hampshire. Once the bird fledges, he begins flying west little by little to look for a good territory to attract a mate. In its first year, the bird travels 10.3 km. In his second year, the bird travels 12.4 km. In his third year, the bird travels 6.4 km until summer, when he finds a female and mates. He does not travel any more in the third year. In the spring of the fourth year, after his young have fledged, the male sets off westward again and travels 9.7 km before a falcon eats him. What was the lifetime dispersal distance of the bird?

29.1 km


Generally, populations contain the highest density of individuals _____.

near the center of their geographic range


You are a pelican searching for fish in the ocean from high in the sky. Although you see no tasty fish in the open ocean, you soon pass over a series of protected lagoons around an island. Each lagoon contains lots of your favorite fish. As you begin descending into one lagoon, you notice that the fish are aggregated into several schools. Some of these schools are close to each other, while others are far apart, and you cannot determine any consistent pattern in the distance between the schools. As you descend even closer to the water above a single school, you notice that each fish is approximately the same distance from each other fish. Beginning from where you first saw the fish, describe, in order, what patterns of dispersion you noticed the fish exhibiting.

clustered → random → evenly spaced


You are conducting a research project examining the spatial structure and movement of an endangered forest-dwelling bird species across the fragmented landscape where it is endemic. During your study, you collect data on the type and amount of resources available for the bird in all forest patches throughout its geographical range. In each of these forest patches, you also carefully document the immigration and emigration of individuals, colonization of new patches, and extinction events. If these are the only data that you collect, you are using the _____ model.

source-sink metapopulation


You are performing a mark-recapture survey of sea turtles that breed on a beach on the east coast of Brazil once every year. In the initial sample, you capture 134 sea turtles and mark their shells. The next year, you return to the same beach and capture 157 sea turtles. Of those individuals, you find that 87 have markers from the previous year's survey. What do you estimate is the approximate size of the sea turtle population that reproduces on this beach?



You are walking through a forest understory when you come across an oak tree. You look at the forest floor and see many hundreds of acorns on the ground around the tree, but as you walk away from the tree, you notice fewer and fewer acorns until you eventually come to another tree, around which you observe the same pattern. Next, you come across a weedy understory plant whose wind-borne seeds will begin germinating wherever they land. Some of these seeds land close together; others land far from any other seeds. Finally, you see a vegetatively reproducing plant with an extensive root system that sends up a shoot approximately every 0.25 meters in every direction. In order, which patterns of dispersion did you observe on your walk from these plants that use very different mechanisms of dispersal?

clustered, random, evenly spaced


Why is the realized niche of a species considered to be a subset of its fundamental niche?

The fundamental niche is the area of a species' livable range of abiotic conditions, but the realized niche is the area other organisms do not prevent the species from occupying.


How could scientists use ecological niche modeling to fight the spread of the introduced emerald ash borer in North America?

Identify places to monitor in North America that have habitat characteristics similar to the emerald ash borer's native range


In terms of metapopulation modeling, what is a dispersal barrier?

Unsuitable habitat surrounding suitable habitat.


Amphibians are animals that begin their lives in water or in a protective, wet, jelly‑like coating. Most amphibians also live part of their juvenile or adult lives on land. Although they have lungs, amphibians supplement their breathing through their skin. Their skin must stay minimally moist for the gas exchange to take place.

What are potential dispersal barriers for North American amphibians that migrate northward due to climate change?


paved parking lots

clearcut forest


Ecologists use the landscape metapopulation model to plan habitat restoration for specific species. What unique information do ecologists need for the landscape model as compared to the other two types of metapopulation models?

quality of matrix surrounding the habitats


Suppose that a scientist captures 20 fiddler crabs in a small freshwater pond and marks them before releasing them back to the pond. The following week, the scientist returns and captures 30 fiddler crabs, six of which are marked. What is the estimated size of the fiddler crab population?

State your answer as a whole number.



Why does a bird species typically have its highest population densities near the center of its geographic range?

The biotic and abiotic conditions at the center of the birds' geographic range are most ideal and support more individuals compared to the periphery.


Why does the density of a population tend to be negatively correlated to the adult body size of the species?

In species that live at high population densities, individuals have limited space for existing and obtaining resources, which restricts growth of individuals to a small body size.


What is the difference between population distribution and population dispersion?

Population dispersion is the spacing of individuals with respect to one another within a population.


A realized niche is

the range of abiotic and biotic conditions in which a species persists.


The American bullfrog is native to eastern North America, but it has been moved by humans and thrives in western North America. What does this suggest about the cause of the bullfrog’s historical range limit?

It was caused by an environmental barrier.


The spread of introduced species can be predicted using

ecological niche modeling.


What mechanisms could cause evenly spaced distributions of individuals within populations?

territorial animals


Suppose that 100 cattle were allowed to graze in either one of two pastures. If the grass was three times as productive in pasture A as in pasture B, how many cows would you expect in pasture A according to the ideal free distribution?



Which model includes consideration of the quality of the surrounding matrix?

the landscape model


Plant A has seeds that are carried by the wind and plant B has seeds that are distributed by gravity. How would lifetime dispersal distance and neighborhood size differ for plants A and B

A would have a greater lifetime dispersal distance and larger neighborhood size.