chapter 45: community and ecosystem ecology

Question 1

Two communities may have exactly the same number of species, yet one might be measured as having a greater species diversity. What defines species diversity?
a.
A community and all of the abiotic factors associated with it

b.
Composition or a listing of the various species in a community

c.
Both the number of species and the abundance of individuals of the different species

d.
The native species plus the introduced species

e.
The potential number of species that should exist in a community minus the species that have gone locally extinct

Answer 1

c.
Both the number of species and the abundance of individuals of the different species

Question 2

As animals take in food energy, approximately 10% of it is made available to the next level in the food chain. Which of the following is one of the ways in which the energy is used by the organism and not passed along?
a.
Excretion

b.
All of these are ways in which the organism uses the energy

c.
Death

d.
Cellular respiration

e.
Defecation

Answer 2

b.
All of these are ways in which the organism uses the energy

Question 3

Chemical cycling may involve all but which of the following?
a.
A biotic community in which chemicals move through food chains

b.
All of the choices are correct

c.
An exchange pool as a source from which organisms can acquire chemicals

d.
A geological component, in which chemicals move through the soil or the air

e.
A reservoir unavailable to producers

Answer 3

b.
All of the choices are correct

Question 4

Compared with the numbers of grasshoppers or deer, there are not as many mountain lions. The reason that large top-level carnivores are more rare in an ecosystem is because
a.
such animals do not tolerate other members like them

b.
through natural selection, most fierce animals have been killed off by others

c.
food chains are only about 10% efficient at each step, and top carnivores are therefore limited by the availability of food in their range

d.
only a few such animals are permitted by succession in a biome, and there are only a few biomes

Answer 4

c.
food chains are only about 10% efficient at each step, and top carnivores are therefore limited by the availability of food in their range

Question 5

What is the correct order of events during primary succession?
a.
Pioneer species enter the region - climax status is reached - small trees begin to grow

b.
Pioneer species enter the region - shrubs begin to grow - small trees begin to grow

c.
Soil formation occurs - pioneer species enter the region - shrubs begin to grow - small trees begin to grow

d.
Pioneer species enter the region - soil formation occurs - shrubs begin to grow - small trees begin to grow

Answer 5

c.
Soil formation occurs - pioneer species enter the region - shrubs begin to grow - small trees begin to grow

Question 6

what is a community

Answer 6

Assemblage of species interacting with one another within same environment

Question 7

what are the three components of a community

Answer 7

1. species richness
2. species abundance
3. species diversity

Question 8

what is species richness

Answer 8

number of species in community

Question 9

what is species abundance

Answer 9

number of individuals of each species

Question 10

what is species diversity

Answer 10

different number of species in an area (species richness) and number of individuals within each species (species abundance). Measure of variety in ecosystem

Question 11

what is the island biogeography model

Answer 11

Proposes that biodiversity on an island is dependent on its distance from mainland, with islands located at a greater distance having a lower level of diversity
-Useful information for conservation areas
-“Islands” of habitats can come in many forms!

Question 12

what is a habitat

Answer 12

Place where an organism lives and is able to survive & reproduce

Question 13

what is an ecological niche

Answer 13

-Role an organism plays in its community, including its habitat & its interactions with other organisms
-Acquire resources to meet energy, nutrient, & survival needs

Question 14

what is a fundamental niche

Answer 14

comprises all the abiotic conditions under which a species can survive when adverse biotic conditions are absent

Question 15

what is a realized niche

Answer 15

comprises conditions under which a species does survive when adverse biotic interactions are present

Question 16

what is the competition exclusion principle

Answer 16

Theory that two species cannot occupy the same niche in the same place and at the same time
-Possible for two species to have different ecological niches

Question 17

what is resource partitioning

Answer 17

Mechanism that increases number of niches by dividing resource, such as food or living space, among species

Question 18

what is competition between populations

Answer 18

-Tendency for characteristics to be more divergent when populations belong to the same community than when they are isolated
-Competition & resource partitioning has taken place

Question 19

what is predation

Answer 19

Interaction in which one organism (the predator) uses another (the prey) as a food source
-Parasitism can be considered type of predation

Question 20

what is camouflage

Answer 20

ability to blend into background

Question 21

what is warning coloration

Answer 21

antipredator defense among animals that tells predator that prey is potentially dangerous
-Many other animals have false eyespots/elaborate structures that cause startle response

Question 22

what is mimicry

Answer 22

Superficial resemblance of two or more species; a survival mechanism that avoids predation by appearing to be noxious

Question 23

what is a batesian mimic

Answer 23

mimic that lacks the defense of the organism it resembles

Question 24

what is a mullerian mimic

Answer 24

share the same protective defense

Question 25

what is symbiosis

Answer 25

close association between two different species over long period of time

Question 26

what is parasitism

Answer 26

one species benefits in terms of growth & reproduction to detriment of other species
-Small parasites tend to be endoparasites
-Larger parasites tend to be ectoparasites

Question 27

what is commensalism

Answer 27

one species is benefited & other is neither benefited nor harmed
-Many examples turn out to be either mutualism or parasitism

Question 28

what is mutualism

Answer 28

both members of association benefit
-Need not be equally beneficial to both species
-Often help each other obtain food or avoid predation
-Plants & their pollinators
-example of coevolution

Question 29

what is coevolution

Answer 29

Mutual evolution in which two species exert selective pressures on the other species

Question 30

what is ecological succession

Answer 30

gradual change in makeup of a community following a disturbance (secondary succession) or beginning with creation of new soil (primary succession)

Question 31

what is primary succession

Answer 31

formation of soil from exposed rock due to wind, water, & other abiotic factors

Question 32

what is secondary succession

Answer 32

disturbance-based succession in which there is a progressive change from grasses to shrubs to a mixture of shrubs & trees

Question 33

what is an ecosystem

Answer 33

Biological community together with the associated abiotic environment; characterized by a flow of energy and a cycling of inorganic nutrients

Question 34

what are abiotic components of an ecosystem

Answer 34

atmosphere, water, and soil

Question 35

what are biotic components of an ecosystem

Answer 35

living things that can be categorized according to their food source

Question 36

what are autotrophs

Answer 36

Organism that can capture energy & synthesize organic molecules from inorganic nutrients
-Photosynthesis or chemosynthesis

Question 37

what are producers

Answer 37

Photosynthetic organism at start of a grazing food chain that makes its own food

Question 38

what are heterotrophs

Answer 38

Organism that cannot synthesize needed organic compounds from inorganic substances & therefore must take in organic food

Question 39

what are consumers

Answer 39

Organism that feeds on another organism in a food chain

Question 40

what are herbivores

Answer 40

Primary consumer in grazing food chain

Question 41

what are carnivores

Answer 41

Consumer in food chain that eats other animals

Question 42

what are omnivores

Answer 42

Organism in food chain that feeds on both plants & animals

Question 43

what are detritivores

Answer 43

Any organism that obtains most of its nutrients from the detritus in an ecosystem

Question 44

what are decomposers

Answer 44

Organism that breaks down organic matter into inorganic nutrients that can be recycled in environment

Question 45

how does energy flow and chemical cycling work

Answer 45

-Ecosystem characterized: energy flow & chemical cycling
-Energy flows begins when producer absorbs solar energy
-Chemical cycling begins when producers take in inorganic nutrients

Question 46

characteristics of energy flow

Answer 46

-Small amount of nutrients consumed by lower-level consumers is available to higher-level consumers
-Elimination of feces, urine, & death of an organism nutrients become available for decomposers
-Covert organic nutrients back into inorganic chemicals (carbon dioxide & water)
-Not cyclic

Question 47

what is the food chain

Answer 47

diagram showing a single path of energy flow in an ecosystem

Question 48

what is a food web

Answer 48

represents interconnecting paths of energy flow within ecosystems

Question 49

what is a trophic level

Answer 49

feeding level of one or more populations in a food web

Question 50

how much energy in one trophic level is available to the next

Answer 50

about 10%

Question 51

what are ecological pyramids

Answer 51

depict the flow of energy with large losses between successive trophic levels
-Based on the number of organisms or the amount of biomass at each trophic level

Question 52

what are biogeochemical cycles

Answer 52

Circulating pathway of elements such as carbon & nitrogen, involving exchange pools, storage areas, & biotic communities
Sedimentary or gaseous

Question 53

what are the four biogeochemical cycles

Answer 53

1. water cycle
2. carbon cycle
3. phosphorus cycle
4. nitrogen cycle