Question 1

The organismal concept of communities argues that species distributions along environmental gradients form clusters because they are interdependent.

Accepted Answer

A) True 
 B)False  True

Question 2

The view of communities as species responding independently to the underlying features of the environment, rather than being interdependent, is referred to as the ________ concept of communities.

Accepted Answer

A) autogenic 
B) organismal 
C) individualistic, or continuum 
D) allogenic 
A) autogenic 
B) organismal 
C) individualistic, or continuum 
D) allogenic C

Question 3

Using specific examples for each, describe the differences between autogenic and allogenic environmental changes that drive succession.

Accepted Answer

Autogenic and allogenic environmental changes are two different drivers of succession in ecosystems. Autogenic changes are those that are driven by the organisms within the ecosystem, while allogenic changes are driven by external factors such as climate, weather, or geological events.

One specific example of autogenic environmental change driving succession is the accumulation of organic matter in a forest ecosystem. As trees and other plants die and decompose, they contribute to the build-up of organic matter in the soil. This accumulation of organic matter can change the soil structure and nutrient availability, which in turn can influence the types of plants that are able to grow in the area. Over time, this process can lead to a shift in the dominant plant species and overall ecosystem structure.

On the other hand, allogenic environmental changes can be exemplified by a flood event in a river ecosystem. When a river floods, it can drastically alter the physical environment by depositing new sediments, changing the flow patterns, and eroding the riverbanks. These changes can directly impact the types of plants and animals that are able to survive in the area, leading to a shift in the species composition and overall ecosystem dynamics.

In summary, autogenic environmental changes are driven by the interactions and processes of the organisms within the ecosystem, while allogenic environmental changes are driven by external factors. Both types of changes play important roles in driving succession and shaping the development of ecosystems over time.

Question 4

Explain the difference between the organismal concept of communities and the individualistic continuum concept. Which do you think most accurately describes real communities and why?

Accepted Answer

The organismal concept of communities vi

Question 5

Communities vary in composition over space but usually not in composition over time.

Accepted Answer

A) True 
 B)False

Question 6

The tolerance model of succession posits that later successional species are neither inhibited nor aided by species of earlier stages.

Accepted Answer

A) True 
 B)False

Question 7

High growth rates, smaller size, high degree of dispersal, and high rates of population growth are typical of ________ successional species.

Accepted Answer

The answer of High growth rates, smaller size, high degree...

Question 8

A good example of succession involving heterotrophic species occurs when dead organic matter is decomposed over long periods of time.

Accepted Answer

A) True 
 B)False

Question 9

________ environmental change is due to a change in the physical environment that is independent of the species in the community.

Accepted Answer

The answer of ________ environmental change is due to a...

Question 10

Briefly describe the cycle of succession in marshes.

Accepted Answer

The marsh cycle is driven by rainfall an

Question 11

Succession usually involves only autotrophic species such as plants.

Accepted Answer

A) True 
 B)False

Question 12

The inhibition model of succession involves strong competitive interactions with the first species to arrive maintaining its position until it is weakened or dies, after which it yields space to another species.

Accepted Answer

A) True 
 B)False

Question 13

Using specific examples for each, explain the differences between primary and secondary succession.

Accepted Answer

Primary succession and secondary success

Question 14

An example of secondary succession is

Accepted Answer

A) grasses colonizing sand dunes. 
B) lichens colonizing a rock. 
C) weeds colonizing a volcanic lava flow. 
D) crabgrass colonizing an abandoned wheat field. 
A) grasses colonizing sand dunes. 
B) lichens colonizing a rock. 
C) weeds colonizing a volcanic lava flow. 
D) crabgrass colonizing an abandoned wheat field.

Question 15

Changes in community composition and structure over time are called

Accepted Answer

A) succession. 
B) stratification. 
C) zonation. 
D) characterization. 
A) succession. 
B) stratification. 
C) zonation. 
D) characterization.

Question 16

Changes in temperature and precipitation are examples of ________ changes.

Accepted Answer

A) autogenic 
B) allogenic 
C) unpredictable 
D) inconsequential 
A) autogenic 
B) allogenic 
C) unpredictable 
D) inconsequential

Question 17

________ environmental change is change that is a direct result of the organisms within the community.

Accepted Answer

The answer of ________ environmental change is change that is...

Question 18

Canada contains approximately ________ of the world's old growth forests.

Accepted Answer

A) 1/10 
B) 1/5 
C) 1/4 
D) 1/3 
A) 1/10 
B) 1/5 
C) 1/4 
D) 1/3

Question 19

Early successional species are usually long-lived and slow-growing.

Accepted Answer

A) True 
 B)False

Question 20

Pollen preserved within lake sediments can be used to reconstruct historical changes in the geographic ranges of plant species.

Accepted Answer

A) True 
 B)False

Exam 17: Community Dynamics

The organismal concept of communities argues that species distributions along environmental gradients form clusters because they are interdependent.

The view of communities as species responding independently to the underlying features of the environment, rather than being interdependent, is referred to as the ________ concept of communities.

Using specific examples for each, describe the differences between autogenic and allogenic environmental changes that drive succession.

Explain the difference between the organismal concept of communities and the individualistic continuum concept. Which do you think most accurately describes real communities and why?

Communities vary in composition over space but usually not in composition over time.

The tolerance model of succession posits that later successional species are neither inhibited nor aided by species of earlier stages.

High growth rates, smaller size, high degree of dispersal, and high rates of population growth are typical of ________ successional species.

A good example of succession involving heterotrophic species occurs when dead organic matter is decomposed over long periods of time.

________ environmental change is due to a change in the physical environment that is independent of the species in the community.

Briefly describe the cycle of succession in marshes.

Succession usually involves only autotrophic species such as plants.

The inhibition model of succession involves strong competitive interactions with the first species to arrive maintaining its position until it is weakened or dies, after which it yields space to another species.

Using specific examples for each, explain the differences between primary and secondary succession.

An example of secondary succession is

Changes in community composition and structure over time are called

Changes in temperature and precipitation are examples of ________ changes.

________ environmental change is change that is a direct result of the organisms within the community.

Canada contains approximately ________ of the world's old growth forests.

Early successional species are usually long-lived and slow-growing.

Pollen preserved within lake sediments can be used to reconstruct historical changes in the geographic ranges of plant species.

The Nature of Ecology

Climate

The Aquatic Environment

The Terrestrial Environment

Ecological Genetics: Adaptation and Natural Selection

Plant Adaptations to the Environment

Animal Adaptations to the Environment

Life History Patterns

Properties of Populations

Population Growth

Intraspecific Population Regulation

Metapopulations

Interspecific Competition

Predation

Parasitism and Mutualism

Community Structure

Landscape Ecology

Systems Ecology

Ecosystem Energetic

Decomposition and Nutrient Cycling

Biogeochemical Cycles

Terrestrial Ecosystems

Aquatic Ecosystems

Coastal and Wetland Ecosystems

Population Growth, Resource Use, and Sustainability

Conservation Ecology

Global Climate Change

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