Chapter 7

Question 0

What is one way ecologists distinguish between biological communities?

Answer 0

Describing their overall physical appearance: relative sizes, stratification, and distribution of the populations and species in each community.

Question 1

What kind of species is the American alligator, and why is it important to protect them?

Answer 1

Keystone species; dozens of aquatic and bird species would disappear from subtropical wetland communities if they died out. Their holes hold freshwater and they limit the population of bass, trees, and shrubs. These alligators were once on the endangered species list in 1967.

Question 2

Species diversity

Answer 2

Species richness combined with species evenness

Question 3

Species richness

Answer 3

of different species a community contains

Question 4

Species evenness

Answer 4

The abundance of individuals in each species

Question 5

Niche structure

Answer 5

How many potential ecological niches occur, how they resemble or differ from one another, and how the species occupying different niches interact

Question 6

Where is species diversity the highest?

Answer 6

The tropics, and it declined as we move from the equator toward the poles. The tropics have a constant daily climate, and reliable food sources, so they tend to be specialist species.

Question 7

Three characteristics of community structure

Answer 7

Species diversity, niche structure, physical appearance (stratification(layers) and size of species)

Question 8

Native species

Answer 8

Species that normally live and thrive in a particular community

Question 9

Nonnative species (invasive, alien) plus a bad example and good example

Answer 9

Species that migrate into or are deliberately or accidentally introduced into a community
Bad: wild African “killer” bees in Brazil
Good: chickens, cattle

Question 10

Indicator species plus example

Answer 10

Species that serve as early warnings of damage to a community or an ecosystem
Ex: canaries in coal mines, butterflies

Question 11

Why are amphibians vanishing?

Answer 11

Habitat loss, prolonged droubt, pollution, increased in ultraviolet radiation, parasites, viral and fungal disease, climate change, overhunting, nonnative species
(Don’t need to know all, but be familiar with the case study)

Question 12

Keystone species and example

Answer 12

They have a large effect on the types and abundances of species in a community (like a keystone which holds an arch together). They play critical ecological roles in helping sustain a community.
Ex: dung beetle, bird, trout, sea otter, wolf

Question 13

Foundation species and example

Answer 13

Create an enhance a habitat in ways that benefit other species
Ex: elephants knock over trees that make room for grass for smaller species

Question 14

Five basic types of interactions between species

Answer 14

Interspecific competition, predation, parasitism, mutualism, commensalism

Question 15

Interspecific competition

Answer 15

Competition for shared or limited resources. Limits population size, agent of natural selection.

Question 16

How can competition for resources be reduced?

Answer 16

Resource partitioning: species become more specialized so they use resources at different times, in different ways, or in different places

Question 17

Predation

Answer 17

One species (predator) feed directly on all or part of a living organism (they prey). 
Ex: lions and zebras

Question 18

How do predators increase their chances of getting a meal?

Answer 18

Herbivores: walk up to food
Carnivores: pursuit and ambush; running fast
Camouflage
Attack w/ poison etc.

Question 19

How to prey defend against or avoid predators?

Answer 19

Ability to run, swim, or fly fast.
Protective shells or thorns
Camouflage
Chemical warfare (irritating, poison, foul smelling)

Question 20

Parasitism

Answer 20

Feeds of part of an organism, usually by living on or in the host.
Don’t usually kill host

Question 21

Mutualism

Answer 21

Species benefit each other

Ex: honeybees, caterpillars, butterflies or clownfish and sea anemones

Question 22

Commensalism

Answer 22

Benefits one species but has little effect on the other.

Ex: birds nests in trees

Question 23

Ecological succession and two types

Answer 23

Gradual change in species composition of an area. Primary and secondary succession

Question 24

Primary succession

Answer 24

No soil. Rocks to lichen, mosses to small shrubs, herbs to heath mat to small trees to big trees

Question 25

Secondary succession

Answer 25

Soil.

Annual weeds to weeds and grasses to shrubs and pine seedings to young forest to mature forest

Question 26

Can we predict the path of succession and is nature in balance?

Answer 26

No, scientists cannot predict it or view it as preordained progress toward a stable climax community that is in balance with its environment.

Question 27

Three aspects of stability or sustainability in living ecosystems

Answer 27

Inertia, persistence: ability of living system to resist being disturbed or altered
Constancy: ability of living system to keep its numbers within limits imposed by available resources
Resilience: ability of living system to bounce back and repair damage after disturbance that isn’t too drastic

Question 28

Does having a lot of species increase or decrease sustainability of communities and why?

Answer 28

It increases sustainability because biodiversity provides insurance against catastrophe.

Question 29

Why should we bother to protect natural systems?

Answer 29

Human activities are disrupting ecosystem services that support and sustain all life and all economies.

Question 30

Symbiosis and three forms

Answer 30

Two organisms working together: mutualism, commensalism, parasitism

Question 31

What were the first organisms endangered due to greenhouse gases?

Answer 31

Polar bears

Question 32

True or false? If you urbanize an area, ecological diversity is decreased.

Answer 32

True.

Question 33

Two types of niches

Answer 33

Fundamental: all of the places a species could live
Realized: where they actually live (real)

Question 34

Generalist v. Specialist

Answer 34

Generalist: can live and eat in more diverse regions
Specialist: specific niche

Question 35

Four types of interspecific competition

Answer 35

Exploitation competition, competitive exclusion principle, resource partitioning, character displacement (Darwin’s Origin of Species)

Question 36

Aquatic succession

Answer 36

Water deposits soil, plants grow, meadow becomes forest

Question 37

Fire is important for which three biomes?

Answer 37

Chaparral, taiga, savanna