bis 2b mt 02

what factors influences population growth?

# of births, # of deaths, # of immigrants, # of emigrants

for population size, what does it mean when r > 0?

population is increasing over time

for population size, what does it mean when r = 0?

population remains the same

for population size, what does it mean when r < 0?

population is decreasing

what is one method for estimating population size?

mark/recapture

what happens in mark/recapture?

mark: capture some individuals and visually tag or mark them

recapture: release the ind. into the wild, wait long enough for them to evenly spread through the population, and then, recapture a second set of ind. to see how many are marked.

R/C = M/N, where:

* N = total pop. size
* M = the # of caught, marked, and released (1st sampling)
* C = # caught in second sampling
* R = the # of marked ind. recaptured in 2nd sampling

the ratio of tagged ind. in our second sampling should equal # of tagged ind. in FULL population

can population size increase exponentially forever? why or why not?

no because at some point, some kind of factor will limit size of popuation

density independent controls

factors (usually abiotic) affecting pop. size that DO NOT depend on the # of organisms in the population

* factors affect pop. in the same way, regardless of how many ind. there are

density dependent controls

factors (usually biotic) affecting pop. size that DO depend on the number of organisms in the population

* has a stronger impact on pop., when there are more individuals in pop.

alcohol is produced as a byproduct of fermentation of sugar by yeast. the maximum ABV% that a solution can achieve is \~15% because yeast cannot survive in higher concentrations of waste products. this is an example of…

a. density dependent control

b. density independent control

a. density dependent control

* this is because more individuals → more waste

wildfire is an example of…

a. density independent control

b. density dependent control

b. density dependent control

* this is because we are talking about the species that are the fuel. the answer would be ‘a’ if we are referencing the species that are not the fuel.

when N_0 is large, (K - N_0) = 0 (approx.), (K - N_0)/K = 0 (approx) and…

growth is slow

when N_0 is small, (K - N_0) = K (approx.), (K - N_0)/K = 1 (approx) and…

growth is *mostly* exponential

survivorship

the proportion of individuals surviving from birth to age class *x*, represented by *l_x*

fecundity

the avg. # of offspring an individual will produce during age class *x*, represented by *m_x*

* tells us how much reproduction is occurring __per__ individual
* not how many babies were produced per individual

R_0

the net reproductive rate; the mean # of offspring produced per individual across their lifetime

* represented by Σ*lxmx* (a.k.a. survivorship x fecundity)

G

generation time; average age of parents across all offspring produced

* average age of production
* G = *xl_xm_x* (for ind.)

what is r in terms of R_0 and G?

r is approx. \[ln(R_0)\]/G

R_0 and r are (positively/negatively/not) related

positively

if R_0 = 1

the population is not changing

* each ind. only has ONE offspring, replacing itself in next gen.

higher survivorship at large juvenile stages leads to

higher reprodctive power later on

r is correlated with the number of individuals at the

reproductive age

if there is a large proportion of ind. at reproductive ages,

large r

how could the fossil record provide evidence for gradualism?

gradual difference in the fossils over time

descent with modification produces

homologous traits

homologous traits

traits that are similar in different organisms because they were inherited from common ancestor

convergent evolution produces

analogous traits

analogous traits

traits similar in different organisms because of similar selective pressure

arew wings analogous or homologous?

analagous

* common ancestor of all mammals did not have wings as not every mammal has wings

which of the following evolves (in scienctific terms)?

a. some populations

b. all populations

b. all populations - evolving at all times

evolution

genetic change over time

adaptation

a type of evolution that occurs through natural selection

microevolution (within ____)

species; changes in genetic variants over generations

macroevolution

speciation; btwn. species; accumulation of many microevolutionary changes, such that new groups arise

4 conditions for natural selection

reproduction, variation, inheritance, success

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what kind of selection is this?

stabilizing selection

Stabilizing selection

Phenotypes nearest the mean have the highest fitness. The mean stays the same and variation is reduced.

what kind of selection is shown below?

Directional selection

Directional selection

Phenotypes at one extreme have the highest fitness, and the mean trends toward that extreme.

What kind of selection is shown below?

Disruptive (diversifying) selection

Disruptive (diversifying) selection

Phenotypes at both extremes have higher fitness than the mean. variation is increased, and bimodal pattern emerges

* intermediate have lowest fitness

Balancing selection is also known as

Frequency dependent selection

Balancing selection maintains

variation in a population

Frequency-dependent selection

Rarer phenotypes have the highest fitness. frequency of a given phenotype oscillates.

* will always see oscillation over time
* variation is maintained

Sexual selection is selection driven by

* Competition for mates
* mate choice

Altruism

A behaviour that reduces individual fitness and increases the fitness of other individuals

Kin selection

Favors behaviors that increase the reproductive success of relatives

Inclusive fitness

The sum of an individual's own fitness, and its contribution to the duchess success/survival of relatives

hamilton’s rule

rB = C, where:

* r = coefficient of relatedness: the fraction of genes shared between relatives
* B = benefit to relative: the increase in offspring for the relative
* C = cost to the altruist: the loss in offspring for the altruist

reciprocal altruism

when the altruist has a reasonable expectation that the sacrifice will be reciprocated in the future

* need to have repeated interactions with the same individual

What are constraints of natural selection?

laws of physics, evolutionary history, trade offs, lack of variation

At what scale do human differ in their genetic make up?

A. Alleles

B. Genes

C. Chromosomes

D. Genomes

A. Alleles

Alleles

Different versions of a gene

Gene

A section of DNA that codes for a particular trait

Chromosomes

A long strand of DNA containing hundreds to thousands of genes

How many pairs of chromosomes does a person have?

23

Genome

All the genetic material an individual carries

Nucleotides

Organic molecules that make up DNA and RNA

what are the possible nucleotides in DNA?

adenine, guanine, thymine, cytosine

What are the possible nucleotides in RNA?

adenine, uracil, cytosine, and guanine

what are the nucleotide pairings in DNA?

thymine pairs with adenine, and cytosine pairs with guanine

What are the nucleotide pairings in RNA?

Uracil pairs with adenine, and cytosine pairs with guanine

The Central dogma

The flow in of genetic information through the two-step process of transcription (DNA → RNA) and translation (RNA → proteins)

DNA is (__) stranded

Double

The sense strand and the antisense strand should look the (__) except the (__)

same; Us and Ts

what happens to the antisense strand?

It gets transcribed into RNA

What happens during translation, and where does it occur?

RNA → protein, occurs in the cytoplasm with the help of tRNA

In translation, the anticodon

binds in to the mRNA and adds their amino acid

the anticodon should be (__) to the mRNA

complementary

The genetic code won’t work well if:

* there is no start/stop codon
* if the stop codon is too early

Primary protein structure

Sequence of a chain of amino acids

Secondary protein structure

Hydrogen bonding of the peptide backbone causes the amino acids to fold into a repeating pattern

tertiary protein structure

3D Folding pattern of a protein due to side chain interactions

Quaternary protein structure

Protein consisting of more than one amino acid chain

Different alleles produce

Different phenotypes of the same trait

Different phenotypes can result from the

* Amount of mRNA transcribed (produce more mRNA, could produce more protein → different phenotype)
* different amino acid sequences

What are three of types mutations?

* substitution: a nucleotide is exchanged
* insertion: a nucleotide is added
* deletion: a nucleotide is removed

Mutations are more likely to have an effect if they happen in

Protein coding regions

The E. coli genome is 87.8% protein coding (compared to 1.5% in humans). Which of the following would you expect to be true?

A. Mutations are mortar likely to be beneficial (increase fitness) in humans.

B. Mutations are more likely to be deleterious (causes lower fitness) in E. coli.

C. There are probably more mutations in humans

D. there are probably more mutations in E. coli

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B. Mutations are more likely to be deleterious (causes lower fitness) in E. coli.

Particulate model of inheritance

Traits passed down as discrete units rather than being blended together

Law of segregation

When any individual produces gametes, the 2 copies of the genes separate so that each gamete receives only one copy

Law of independent assortment

Alleles of different genes assort independently of one another during gamete formation

* what happens to one gene doesn’t affect what happens to another gene

Diploid

Having 2 copies of each chromosome (2n)

Meiosis is used for

Making gametes

What is the result of meiosis 1?

2 cells containing duplicates of 1 chromosome

What is the result of meiosis 2?

4 cello containing 1 chromosome each

What are the 3 types of dominance?

* complete dominance
* incomplete dominance
* codominance

Complete dominance

A single dominant allele produces the dominant phenotype. the homozygous dominant and heterozygous genotypes have the same phenotype

Incomplete dominance

The heterozygote phenotype is intermediate between the two homozygous phenotypes

Codominance

The heterozygote shows both the homozygous phenotypes

Do dominant traits skip generations?

No.

Recombination

The rearrangement of genetic material, especially by crossing over in chromosomes or by artificial joining of segments of DNA from different organisms

* occurs when you have two genes on the same chromosome

Is recombination more likely to occur between 2 genes that are closer together or farther apart?

Farther apart

The likelihood of recombination between two genes is proportional to

The distance between the 2 genes (on the chromosomes)

If you have two linked genes, the parental types (same chromosomes as parents) will always

Have more offspring

offspring than those that require recombination

Phenotype of offspring is entirely determined by

What kind of gameto they get from parent

Linkage mapping

Determining the recombination frequency for numerous genes allows us to map each gene's on the chromosome

One gene affects () characteristic(s)

Multiple

The ‘frizzle’ phenotype in chickens is determined by a a single gene (the F gene). Chickens with the frizzle gene also there's to have increased metabolism. What are potential explanations for this phenomenon?

A. The F gene and the metabolism gene(s) must be on different chromosomes.

B. The F gene and the metabolism gene(s) are very close together on the same chromosome

C. Pleiotropy

B. The F gene and the metabolism gene(s) are very close together on the same chromosome