Chapter 6- Population And Community Ecology

Question 1

How does New Enlgand show the resilience of its forests?

Answer 1

After forests were cleared with settlements, the forests grew back many years later. New species abundance and change in population sizes and distribution.

Question 2

Define population.

Answer 2

All individuals that belong to the same species and live in a given area at a particular time.

Question 3

Define community.

Answer 3

All the populations of organisms within a given area.

Interactions among species.

Question 4

Define biosphere.

Answer 4

The earth. Contains all of earths ecosystems.

Question 5

Define population ecology.

Answer 5

The study of factors that cause populations to increase or decrease.

Question 6

What are 5 basic population characteristics?

Answer 6

Size, density, distribution, sex ratio, and age structure.

Question 7

Define population size

Answer 7

The total number o individuals within a defined area within a given time.

Question 8

Define population density.

Answer 8

Number of jndividuals per unit area at a given time.

Question 9

Define population distribution.

Answer 9

A description of how individuals are distributed with respect to one another. Can be random, uniform, or clumped.

Question 10

Define population sex ratio.

Answer 10

Ratio of males to females.

Question 11

Define population age structure.

Answer 11

A description of how many individuals fit into a particular age categories.

Question 12

What kind of factors can influence population size?

Answer 12

Density dependent and density independent.

Question 13

Define density dependent factors.

Answer 13

Influence an individuals probability of survival and reproduction in a matter that dormers in the size of the population. Ex limiting nutrients.

Question 14

Define carrying capacity.

Answer 14

The limit to how many individuals the food supply could sustain. K.

Question 15

What are density independent factors.

Answer 15

Same effects in probability of survival and reproduction at any population size. Ex tornado.

Question 16

What are population growth models?

Answer 16

Math equations that can be used to predict population size at any moment in time

Question 17

Define growth rate.

Answer 17

The number of offspring an individual can produce in a given time period minus deaths.

Question 18

Define intrinsic growth rate.

Answer 18

Maximum potential for growth. r.

Question 19

Define exponential growth model.

Answer 19

Pop future size= #reproducingindividualse^(growth ratetime)
Is a j shaped curve.

Question 20

Define logistic growth model

Answer 20

A population shoes growth is initially exponential but slows as the population reaches carrying capacity.
Is an s shaped curve.
There are several variation that include overshoots and die offs

Question 21

Define k selected species.

Answer 21

A population in which its abundance is determined by the carrying capacity and fluctuations are small.
Ex elephants.

Question 22

Define r selected species.

Answer 22

Species that reproduce often and produce large numbers of offspring.
Ex Mosquitos.

Question 23

Define survivorship curves.

Answer 23

Patterns of survival over time.

Question 24

Describe te connection between corridors and meta populations.

Answer 24

A meta population is a group of spatially distinct populations that are connected by occasional movement between them- through corridors(strips of habitat).

Question 25

Define community ecology.

Answer 25

The study of interactions that determine the survival of a species in a habitat.

Question 26

Define competition

Answer 26

The struggle of individuals to obtain a limiting resource.

Question 27

Define the competitive exclusion principle.

Answer 27

Two species competing for the same limiting resource cannot coexist. One species will perform better and the other will be driven to extinction.

Question 28

Define resource partitioning.

Answer 28

Competition in which two species divide a resource based on differences in the species behavior or morphology.
Temporal resource partitioning occurs when two species utilize the same source but at different times.
Spatial resource partitioning occurs when two species use two different habitats.
Morphological resource partitioning is when the evolution of differences in body shape or size.

Question 29

Define predation.

Answer 29

The use of one species as a resource by another species predators can be true predators (kill their prey and consume most of what they kill), herbivores, parasites/pathogens, and parasitoids.

Question 30

Define mutualism.

Answer 30

Benefits two interacting species by increasing both species chances of survival.

Question 31

Define symbiotic relationships.

Answer 31

The relationship of two species that live in close association with each other. Embodies commensalism, mutualism, and parasitism.

Question 32

Define commensalism.

Answer 32

One species benefits but the other is neither harmed nor helped.

Question 33

Define keystone species.

Answer 33

A species that plays a role in its community that is far more important than its relative abundance might suggest.

Question 34

Define predator mediate competition.

Answer 34

A predator that mediates the population growth of another predator.

Question 35

Define ecosystem engineers.

Answer 35

A keystone species that creates or maintains habitat for other species.

Question 36

Define ecological succession and two types of it.

Answer 36

The predictable replace it one group of species by another group of softies over time.
Primary succession occurs on surfaces that are initially devoid of soil.
Secondary soul occurs in areas that have been disturbed But have not lost their soil.

Question 37

Define pioneer species.

Answer 37

Species that colonize new areas rapidly and grow well in full sunshine.

Question 38

Define aquatic succession.

Answer 38

Over hundreds to thousands of years lakes are filled works edited and slowly become terrestrial habitats.

Question 39

What are three basic processes that determine the number and types of species present in a biome? What factors are these processes affected by?

Answer 39

Colonization of the area by ew species, speciation within the area and losses from the area by extinction.
Influenced by latitude, time, habitat size, and distance from other communities.

Question 40

Define the theory of island biogeography

Answer 40

Species richness increases as the size if the habitat increases.

The theory of island biogeography proposes that the number of species found on an undisturbed island is determined by immigration and extinction. Immigration and emigration are affected by the distance of an island from a source of colonists (distance effect).