Chapter 2

Question 1

Community

Answer 1

The population of different species that inhabit a given area

Question 2

Ecosystem

Answer 2

The biological community (population) and the physical (abiotic) environment

Question 3

Population

Answer 3

A group of organisms in the same species that inhabit a given area

Question 4

niche (fundamental and realized)

Answer 4

-Role or function of a species in an ecosystem
-Fundamental is every possible thing that could be used, realized is what is used.

Question 5

Succession (1 and 2)

Answer 5

-A change in species in the ecosystem over time
-1: bare rock to vegetation
-2: Already there, just changing

Question 6

Keystone species

Answer 6

A species that other species in an ecosystem are dependent on

Question 7

r and k selected species

Answer 7

-K: Larger animals, long lifespans, few young (elephant)
-R: Small animal, short lifespan, many young (mouse)

Question 8

Carrying capacity

Answer 8

How many species an ecosystem can maintain (K)

Question 9

Trophic levels

Answer 9

Where they are in the food chain (producer, primary consumer, secondary consumer, tertiary consumer, etc.)

Question 10

How is species diversity different from species richness?

Answer 10

Richness is only how many species there are while diversity is how many species AND their relative abundance

Question 11

How are the 3 types of diversity different from each other (alpha, beta, gamma)? How may this affect our interest in preserving a site?

Answer 11

-Alpha: Local, the number of species found in a given community such as a lake or meadow
-Gamma: Regional, the number of species at a larger geographic scale that include a number of ecosystems, such as a mountain range or continent.
-Beta: Ratio (Gamma/Alpha)

-Affects the determination of where the site will be located. Where they want to preserve. Do you want size or diversity?

Question 12

What mechanisms of evolution decrease the genetic diversity of a population?

Answer 12

Natural selection
Genetic drift

Question 13

Why is genetic diversity considered to be important?

Answer 13

To avoid inbreeding and to have the population be diverse enough to allow for adaptations. This helps to protect the population, i.e if there was a disease and all the individuals were genetically identical (or very similar) with no genetic protection, it would wipe them out.

Question 14

How does the impact of genetic drift vary depending on population size or immigration rates?

Answer 14

-A larger population is less likely to have genetic drift
-Immigration rates leads to higher genetic variation, counteracts genetic drift

Question 15

How does the founder effect differ from a population bottleneck? How are they the same?

Answer 15

-Founders Effect: The reduction in genomic variability that occurs when a small group of individuals becomes separated from a larger population.
-Bottleneck Effect: The way in which a reduction and subsequent increase in a population/’s size affects the distribution of genetic variation among its individuals.

Question 16

What is the biological species concept? Why is this sometimes inadequate in naming species? What is a cryptic species?

Answer 16

-The biological species concept defines a species taxon as a group of organisms that can successfully interbreed and produce fertile offspring.
-This can sometimes be inadequate because it cannot help with fossil species, asexual/self-fertilization species, or species with open mating systems, aka freely hybridizing.
-A cryptic species is comprised of two or more taxa that are grounded under a single name because they are more-or-less indistinguishable morphologically

Question 17

How does allopatric speciation differ from sympatric speciation? How can they occur? Which one is most likely part of radiations on island chains?

Answer 17

-Allopatric speciation: When groups separate into different species due to geographical separation whereas sympatric speciation occurs when groups separate into different species without geographical separation
-Allopatric speciation can occur when species live on islands, like the galapagos finches and sympatric speciation separate due to other stressors, such as hawks splitting into two different species because their different beak shapes caused them to catch different prey.

Question 18

What does ecological release (niche expansion) refer to? How can this occur in a species?

Answer 18

a population increase or population explosion that occurs when a species is freed from limiting factors in its environment
i.e a disease or a competitor or a keystone species, such as a top predator, is removed from a community or ecosystem (isle royale)

Question 19

What is an adaptive radiation? Examples?

Answer 19

-The diversification of a group of organisms into forms filling different ecological niches
-i.e bird species on the Hawaiian island chains. Allopatric speciation.

Question 20

What is an endemic species? Why does Hawaii have such a high proportion of endemic species (as compared to what we may on a continent)?

Answer 20

-Endemic species: Species that live in a limited area, only found there
-Hawaii has a high proportion because it is a chain of islands with a limited space, as opposed to a continent where they can move around and migrate to different places.

Question 21

How to species richness change with latitude?

Answer 21

Increases with decreased latitude (closer to the equator)

Question 22

How to species richness change with rainfall (precipitation)?

Answer 22

Increases with increased precipitation

Question 23

How to species richness change with solar radiation?

Answer 23

Increases with increased radiation

Question 24

How to species richness change with the age of the community?

Answer 24

Increases with older communities

Question 25

How to species richness change with size of the area?

Answer 25

Increases with larger area

Question 26

How to species richness change with altitude?

Answer 26

Increases with decreased altitude

Question 27

How to species richness change with topographic complexity?

Answer 27

-Increases with increased topographic complexity.

Question 28

Explain why there are more species in the tropics than temperate areas.

Answer 28

They are closer to the equator, have more consistent weather, more rainfall, more solar radiation, low altitude, large size, and a fairly old community.

Question 29

About how many described species are there? What 2 groups of organisms make up the bulk of the species described?

Answer 29

-2 mill
-Animals and Fungi

Question 30

Explain how Erwin (1982) tried to estimate the number of insects on the planet.

Answer 30

Based on ration, host specificity.
He used the number of beetles found and multiplied it by estimated factors like specialization, total insects, percent of insect in canopy vs rest of tree and number of species of trees.

Question 31

How can accumulation curves be used to estimate the number of species? Using this method, how many Eukaryotes does Mora et al. (2011) estimate are on the planet?

Answer 31

-Gives the expected number of observed species or distinct classes as a function of sampling effort. The more you sample, the more likely you’re not getting more data.
-8.7 mil +/- 1.3 mil