Niche and Evolution

Question 1

What is a Niche?

Answer 1

the environmental conditions (abiotic and biotic) in which an organism can survive, grow and reproduce

Question 2

What is the Hutchinsonian Hypervolume?

Answer 2

the huntchinsonian niche describes a species niche as hypervolume along multiple axes of environmental variables

Question 3

Ecological Niche Modeling

Answer 3

niches are often calculated to predict potential geographic distribution ranges

Question 4

What is the Principle of Allocation?

Answer 4

• the amount of energy available to each organism is limited
• when energy is allocated to one function, it reduces the energy available for other functions

Question 5

What are energy budgets?

Answer 5

within its niche. an organism has a limited amount of energy available that it takes up via food/photosynthesis

no matter the organism, energy acquired must be used for:
- growth
-maintenance
-activity
-reproduction

Question 6

Competitive Exclusion Principle

Answer 6

Gause’s Law
- two species cannot coexist if their niches are the same
- competition may play a role in defining the realized niche

Question 7

What is niche partitioning ?

Answer 7

when a species in a community use limiting factors in different ways (i.e., the occupy different niches)

Question 8

Define Evolution

Answer 8

change in allele (i.e., gene) frequencies within a population over time

Question 9

Darwin’s Finches

Answer 9

1. finches on the archipelago resembled mainland finches
2. species on the archipelago differed in their morphology, especially in beak size and form
3. darwin later concluded that natural selection may be the mechanism underlying evolution

Question 10

What is fitness?

Answer 10

an individuals’ relative genetic contribution to the next generation’s gene pool

Question 11

What are Alleles

Answer 11

different forms of a gene (A,a)

Question 12

What is a gene pool

Answer 12

the sum total of all the alleles in a population

Question 13

What are diploid organisms

Answer 13

one with two alleles of a gene

Question 14

Phenotype

Answer 14

an attribute of an organism, such as its behaviour, morphology or physiology

Question 15

Genotype

Answer 15

-the set of genes an organism carries
-one genotype can produce several different phenotypes, depending on how genes are expressed

Question 16

What Causes phenotypic variation among individuals within a population?

Answer 16

• genetic differences
• environmental factors

Question 17

Phenotypic Plasticity

Answer 17

the ability of one genotype to produce more than one phenotype when exposed to different enviornments

Question 18

Mechanisms of Evolution

Answer 18

changes in gene frequency within a population occur via natural selection and random processes

Question 19

Random processes include

Answer 19

• genetic drift
• bottleneck
• founder effect

Question 20

What is the Hardy-Weinberg Principle

Answer 20

• in an infinitely large population where mating is random and evolutionary forces absent, allele frequencies will remain constant across generations

Question 21

What are some ways the Hardy-Weinberg equilibrium can be disturbed?

Answer 21

mutations, natural selection, non-random mating, genetic drift and gene flow

Question 22

Genetic Drift

Answer 22

a process that occurs when genetic variation is lost because of random variation in mating, fecundity, morality, and inheritance

Question 23

Bottleneck

Answer 23

a reduction in genetic diversity in a population due to a large reduction in population size

Question 24

Founder Effect

Answer 24

a small number of individuals leave a large population to colonize a new area and bring with them only small amount of genetic variation

Question 25

Natural Selection

Answer 25

• many offspring are produced, not all survive
• traits vary among individuals within a population and may be heritable
• some heritable traits give individuals an advantage
• advantageous traits, conferring higher fitness, become more common

Question 26

Directional Selection

Answer 26

natural selection that appears to shift phenotypic variation into specific direction (favouring extreme phenotypes)

Question 27

Disruptive Selection

Answer 27

two or more extreme phenotypes become more frequent and the average phenotype becomes less frequent

Question 28

What is Speciation

Answer 28

the outcome by which species evolve due to physical and ecological processes that interact with natural selection and random processes

Question 29

Biological Species Concept

Answer 29

• Ernst Mayr
• groups of actually or potentially interbreeding populations, which are reproductively isolated from other such group

Question 30

Reproductive Isolation

Answer 30

mechanisms of reproductive isolation before zygote can be formed, such as through geographic isolation, temporal isolation, behavioural isolation, mechanical isolation

Question 31

allopatric speciation

Answer 31

occurs when a single population becomes spatially subdivided into multiple subpopulation

Question 32

sympatric speciation

Answer 32

occurs when a population is not spatially subdivided and interbreeding fails due to non-spatial isolating mechanisms, such as positive assortive mating

Question 33

Parapatric Speciation

Answer 33

• when a population expands into new habitat within the pre-existing range of the parent species and the offspring of these two subpopulations fail to reproduce due to spatial segregation, dispersal limitation, non-random mating,etc
• sometimes considered a form of allopatric speciation