conservation bio final

3 pillars of biodiversity conservation

1. maintenance of ecological processes and life support systems

2. sustainable use of species and ecosystem

3. preservation of genetic diversity

IUCN

International Union for Conservation of Nature

IUCN Red List

A list of worldwide threatened species

variety of genetic information within and between species is known as

genetic diversity

what does higher genetic diversity create

reservoir of potentially beneficial traits that can help populations withstand environmental changes, diseases, or other pressures

high genetic diversity == higher ___ and ____ of species

long term survival; adaptability

main conservation goal

retain a population's evolutionary potential through genetic diversity

evolutionary potential

the potential of a population to change over time according to population size and amount of genetic variaton

how can a population's evolutionary potential be retained through genetic diversity (2)

preserve allelic diversity; prevent allele fixation

different forms of the same gene are known as

alleles

how is genetic variation of a population measured

how many alleles there are for a given gene

when only 1 allele remains in the population for a specific gene

fixation of alleles

why is allele fixation harmful (2)

causes reduced fitness and accumulation of harmful mutations

any change in the frequency of alleles within a population, regardless of whether the change is advantageous is known as

evolution

natural selection is a type of

evolutionary process

when alleles that confer a fitness advantage under given environmental conditions

natural selection

T or F: all evolutionary processes enhance fitness

F; specific to natural selection

example of an evolutionary process that does not improve fitness

genetic drift

polymorphism

the simultaneous occurrence of two or more distinct variant forms (alleles) of a specific DNA sequence within a population

how is polymorphism derived

find # genes for which there is more than 1 allele/# genes total

higher/lower polymorphism=more genetic diversity

higher

average % of individuals heterozygous for a particular gene is known as

heterozygosity

genes for which >1 allele exists is known as

polymorphism

average # of alleles/gene is known as

allelic diversity

eDNA

Environmental DNA used for species detection and dna barcoding

methods of measuring genetic change (4)

mtDNA, PCR, DNA fingerprinting (individuals), eDNA

population management units

distinct, demographically independent groups of organisms—typically wildlife or plants—used in conservation and biology to monitor, assess, and manage populations

movement of alleles from one population to another

gene flow

Genetic changes caused by environmental changes like genetic variation and mutation.

genetic risk

study of mating behaviors in animals

reproductive ecology

small/large populations have a higher risk of extinction

small

small/large populations are more sensitive to sources of stochasticity

small

randomness inherent in a system

stochasiticity

genetic stochasticity aka

drift

small populations are more vulnerable to (3)

stochasticity, inbreeding, allee effect

as n (pop. size) decreases, per capita population growth rate declines

allee effect

Intrinsic random fluctuations in population size that occur because the birth and death of each individual is a discrete and probabilistic event

demographic stochasticity

demographic stochasticity is extrinsic/intrinsic random, environmental stochasticity is extrinsic/intrinsic random,

extrinsic, intrinsic

demograohic stochasticity depends on

timing, birth probability, death probability

Extrinsic random variation in average birth or death rates from year to year because of random changes in environmental conditions

environmental stochasticity

environmental stochasticity depends on

geographic concentration of a population, resources, predators, diseases, natural disasters

T or F: environmental and demographic stochasticity always has a negative effect on population size

F: can be negative or positive effect on population size

when natural events cause very rapid, sudden, and complete increase in death rate in a population

catastrophic stochasticity

allee effect says that as n declines, ___ declines

per capita pop growth rate

reasons for allee effect (4)

difficulty in finding mates, cooperative hunting, and social interaction. more vulnerable to predators

T or F: population growth is highest at low pop. density

F according to allee effect; logarithmic rather than exponential

Random fluctuations in allele frequencies as a result of nonrepresentative combinations of alleles.

genetic drift

when selecting alleles for the next generation from gene pool of the current generation since alleles are not evenly distributed across individuals, limiting genetic diversity captured

sampling error

T or F: genetic drift occurs in all populations

T

genetic drift is problematic in large/small populations

small

why does genetic drift affect small pops more

small pops are more vulnerable to outcomes of individual matings, instead of overall probabilities of inheritance & selection pressures (sampling error)

significance of rare alleles

usually not essential for initial environment, but may help with survival as conditions change

what contributes to a reduction in gene flow

habitat loss/fragmentation

when a population's size is greatly reduced in size for at least one generation. reduces genetic diversity

population bottlenecks

T or F: not all pop reductions create bottlenecks

T

what influences pop reductions occurring without a bottleneck

degree of genetic diversity of survivors

species in US that experienced a significant bottleneck; why?

bison; crossbreeding with cattle and low ancestral genetic diversity

a reduction in fitness (survival & fecundity) of offspring that often arises due to inbreeding among parents

inbreeding depression

T or F: inbreeding always eventually leads to inbreeding depression

F; not always

major consequence of inbreeding

loss of heterozygote advantage, causing lethal/dangerous recessive alleles to have a higher chance of being homozygous and expressed

states heterozygotes have higher fitness than homozygotes

heterozygote advantage

when a small group of individuals establishes a new population, often in a new or isolated habitat.

founder effect

consequence of founder effect

genetic composition may differ from source population, leading to a loss of alleles

How can loss of genetic diversity or inbreeding be counteracted? (2)

mutations and gene flow

strategy to encourage gene flow

habitat corridors

strategy that increases population fitness with introduction of new alleles

genetic rescue

is crossbreeding always bad

no; sometimes subspecies crossbreeding can save a population through introduction of new alleles but can cause loss of unique identity

T or F: counts and censuses are accurate methods to quantify genetic risk

F; effective population size is used instead

metric used for genetic risk analyses

effective population size

why are censuses inaccurate for genetic risk estimations

do not capture differences due to sex ratio, mating patterns, pop size changes

effective population size is given by

Ne

difference between effective population size and actual population size

Ne translates the actual population size into the size of an ideal population that loses heterozygosity at the same rate as the actual population

Ne is typically lower/higher than N

lower

what does an "ideal" pop mean (3)

1. equal pop size (Nm=Nf)

2. constant effective pop size w/ no migration or mutation

3. constant reproductive success

Nm in genetic risk calcs

number of males

Nf in genetic risk calcs

number of females

why is effective pop size important to measure

genetic diversity (heterozygosity) is a function of effective population size

what can be estimated from effective pop size

expected loss of diversity due to genetic drift

Ht, H0, Ne, t in heterozygosity loss equation

Ht=heterozygosity after t generations

H0=original heterozygosity

Ne= effective pop size

t= # of generations

useful metric of genetic diversity

heterozygsity

how to interpret value for heterozygosity

between 0 and 1, 1 is high Ht, 0 is none/very low

Proportion of individuals in a population with 2 different alleles for a given trait

heterozygosity

rate of heterozygosity decline is determined by

how large Ne is

the higher Ne is, the higher/lower Ht is

higher

Ne equation depends on (2)

sex ratio; Nm and Nf

the more equal the sex ratio is, the higher/lower Ne will be

higher

fluctuating population size inc/dec Ne

dec

t in harmonic mean calculations

number of gens

Ni in harmonic mean calculations

census pop in each generation

harmonic mean is used to

account for fluctuating pop size

bottleneck effects on diversity depends on (2)

how small pop becomes

how long it stays small

A downward population spiral in which inbreeding and genetic drift combine to cause a small population to shrink and, unless the spiral is reversed, become extinct.

extinction vortex

Imagine a population evolving by genetic drift, in which the frequency of allele K is 0.8.

What is the probability that at some point in the future allele K will drift to a frequency of 1.0?

0.8

how do genetic drift and natural selection differ

genetic drift happens bc of sampling error, natural selection occurs bc some alleles confer higher fitness

why is it hard to census a species

logistically challenging and expensive

a species that cannot be distinguished from similar species by easily identifiable morphological traits

cryptic species

alternative to census

estimating relative abundance

metric for number individuals spotted or trapped per unit of effort

relative abundance

linear path or line that is systematically laid out across a habitat or landscape to sample

transect

Square sampling grids

quadrats