Chapter 8

Question 1

What are 3 characteristics to describe a biographical community?

Answer 1

1. Physical appearance (sizes, stratification, distribution)
2. Species diversity (species richness and species evenness)
3. Niche structure (# of ecological niches, how they are the same/different)

Question 2

What are factors that affect species diversity?

Answer 2

1. Latitude
2. Pollution
3. Habitat diversity
4. Net primary productivity
5. Habitat disturbance
6. Time

Question 3

How are the number of species on an island determined?

Answer 3

How fast new species arrive and old species become extinct; island size, and how far it is from the mainland

Question 4

What did MacArthur and Wilson study?

Answer 4

Communities on islands to discover why large islands have more species of a certain category, such as insects and birds, than small islands

Question 5

What did MacArthur and Wilson propose?

Answer 5

The species equilibrium model (theory of island biogeography)

Question 6

What does the species equilibrium model state?

Answer 6

Balance between 2 factors: rate at which new species immigrate, and rate at which old species become extinct

Question 7

Which 2 factors affect island immigration/extinction?

Answer 7

1. Island size
2. Island distance from the mainland

Question 8

What is a habitat island?

Answer 8

A national park with sea of developed/fragmented land

Question 9

What is a native species?

Answer 9

A species that normally lives there

Question 10

What are non-native/invasive/alien/exotic species?

Answer 10

Evolve somewhere else then migrate on purpose or accident to another place

Question 11

What is an indicator species?

Answer 11

Provide clues to environmental conditions

Question 12

What is an example of an indicator species?

Answer 12

Presence or absence of trout in water indicates water quality because trout need clean water with high levels of dissolved oxygen

Also - canaries in coal mines (they sing loud/often, when they stop it means too many chemicals in the mine)

Question 13

What is a keystone species?

Answer 13

Help determine types and numbers of various other species in a community. Play critical ecological roles.

Question 14

What is an example of a keystone species?

Answer 14

Beaver: Dam building and pond creating influence the lives of a wide variety of other organisms

Question 15

What experiment did Robert Paine conduct?

Answer 15

He removed sea stars from a community, and left them in another community. The community he removed them from lost 18 species, except for mussels

Question 16

What is a foundation species?

Answer 16

Create and enhance habitats that benefit other species - beavers are keystone species AND foundation species

Question 17

What type of species are elephants?

Answer 17

Foundation, because they push over and break trees, creating forest openings

Question 18

What is competition?

Answer 18

Interaction for shared/scarce resources (space/food)

Question 19

What is interspecific competition?

Answer 19

Competition between species

Question 20

What is predation?

Answer 20

Preying on a species

Question 21

What is parasitism?

Answer 21

Parasite living in/on an organism

Question 22

What is mutualism?

Answer 22

When each species benefits

Question 23

What is commenalism?

Answer 23

When one species benefits, and the other species if neither benefited or harmed

Question 24

What is resource partitioning?

Answer 24

When species competing for similar scarce resources evolve traits that allow them to use shared resources at different times/ways/places

Question 25

What is an example of resource partitioning?

Answer 25

Hawks/owls: hawks hunt during the day, owls hunt at night Lions/leopards: Lions eat big prey, leopards eat smaller prey

Question 26

What do herbivores do?

Answer 26

Walk, swim, or fly to plants they feed on

Question 27

What do carnivores do?

Answer 27

Ambush, stalk, and pursue

Question 28

What are endoparasites?

Answer 28

Parasites that live inside their host organism (ex. tapeworm)

Question 29

What are ectoparasites?

Answer 29

Parasites that live outside ("attach") their host organism (ex. ticks)

Question 30

What are cowbirds?

Answer 30

A brood parasite that lays their eggs in nests of other birds and lets them raise their babies

Question 31

Pollination is an example of what?

Answer 31

Mutualism

Question 32

What is an example of commenalism?

Answer 32

Redwood sorrel, which grows in the shade of a tall redwood tree, but it doesn't affect the tree

Question 33

What is ecological succession?

Answer 33

Gradual change in species composition of a given area

Question 34

What is primary succession?

Answer 34

Gradual establishment of biotic communities on nearly lifeless ground (ex. grass growing on a rock)

Question 35

What is secondary succession?

Answer 35

Biotic communities established in an area with biotic community already present

Question 36

Soil happens when

Answer 36

Pioneer species attach themselves to a rock

Question 37

What are annuals?

Answer 37

Tiny plants that only live for a year

Question 38

What are perennial grasses?

Answer 38

Plants that live 2+ years without needing to reseed

Question 39

What are 3 factors that affect succession?

Answer 39

1. Facilitation: 1 species makes an area suitable 2. Inhibition: Early species hinder growth of other species 3. Tolerance: Late plants unaffected by earlier plans

Question 40

What is disturbance?

Answer 40

A change in environment conditions that disrupts an ecosystem (ex. fire)

Question 41

Are all disturbances bad? Why/why not?

Answer 41

No. For example, when a tree falls in a forest, it increases sunlight and nutrients

Question 42

What is inertia?

Answer 42

The ability to resist being disturbed

Question 43

What is constancy?

Answer 43

The ability of a population to keep its members within limits imposed by available resources

Question 44

What is resilience?

Answer 44

The amount of disturbance a system can absorb without being fundamentally changed

Question 45

What is complexity?

Answer 45

The number of species in a community at each trophic level and the number of trophic levels in a community

Question 46

What did David Tilman state?

Answer 46

Communities with more species have higher productivity

Question 47

What is the precautionary principle?

Answer 47

When there is evidence of human activity that can harm our health, we should take measures to prevent the harm

Question 48

What is species richness?

Answer 48

The number of the same species in a community

Question 49

What is species evenness?

Answer 49

The number of 2 or more species in a community is relatively similar