BIO 201 Test 2

(1) Variation

mutations, genetic variations, independent assortment.

variation is always being added to populations. The variation volcano never stops

(1) Mutations

-mutations occur randomly

-most individuals have mutations

-mutations are helpful, harmful, or have no effect

(1) Genetic Recombination

-Most gametes have different genetic combinations.

-Billions of genetic variations occur in gametes

(1) variation in alleles

extremely high variation

(1) proteins

very high in variation

(1) variation in behavioral and physical traits

high in variation

(1) personal observation

limited variation

(1) documented

larger range of individual’s personal observation

(1) true range of variation

vast and never fully documented

(1) Common Perspective

-personal observation represents true range of variation

-observations should be ignored

-outliers are not normal or how things are supposed to be

-outliers are problematic, or just exceptions

(1) Biological Perspective

-observed variation is a tiny fraction of all variation

-outliers are important representatives

-variation isn’t good or bad

-outliers are new variation for nature to work with

(1) Albinism

-pattern across species (repeated observation) : red eyes, pale skins

-processes (causes and mechanisms): Albinism has the same processes of mutation, recombination and independent assortment

(1) different patterns in locations

same processes of variation along with sorting within each environment results in different patterns

(2) Species

a group of potentially or actually interbreeding organisms that can produce fertile offsprings

(2) Population

a group of individuals of the same species living in the same area

(2) Individual

a single member in a population

(2) Range

full extent of the variety of the phenotype in question within that population

(2) Frequency

The measure of the proportion of individuals with that phenotype

(2) Population vs Species

A population may display a much smaller range of variation than the species as a whole

(2) temporal variation

change over time

(2) spatial variation

difference across locations

(2) how do we measure and quantify these comparisons?

the range and frequency of alleles, genotypes, and phenotypes

(2) Trend

consistent, directional change in data over time

(2) Association

Relationship where one variable changes similarly to another variable over time

(2) Significant Feature

Aspect of the data that is relevant to explaining the pattern

(2) Evolution

is change is occurring over time

can happen through chance alone

(3) Random Chance

lack of order

lack of predictability

lack of pattern

(3) Non-random chance

has order

predictable

has a pattern

(3) Random and non-random sorting

filters out some of this variation to give us the pattern that is seen in the actual population

some individuals survive some do not, some will get to have offsprings some will have few off springs, and some will have no offsprings

(3) Non-random factors

environmental factors: resources available, physical conditions, other species, and more

can impact an individuals ability to survive and reproduce. (how well a phenotype impacts an individuals ability to survive and reproduce)

(3) Random factors

good luck or bad luck, chance

can impact an individuals ability to survive and reproduce

(3) Chance and non-random factors

chance can affect any stage of life

happening all the time and at the same time

(3) fitness

reproductive success: how successful at passing alleles into future generations.

Measured as number of surviving offsprings produced in one’s lifetime

(when looking at a graph always count the most recent data point to determine fitness)

always depends on the environment, no genotype is always the best

(3) Genotypic fitness

average of surviving offsprings among all members of a specific genotype in a population

(4) How to interpret data tables

look for:

Anomalies

Patterns

Trends

Associations

Significant features

(4) Population Bottleneck

a drop in population size in a short period of time.

Small population size = large loss of variation due to random chance

Large population size = small loss of variation due to random chance

(4) Founder event

new smaller population that leave the large population to start another population on their own

creates large loss of variation due to random chance

(4) Genetic Drift

random changes in allele frequencies due to chance are called genetic drift

drop in population size happens, the outcome is genetic drift

Larger population: small genetic drift

Smaller populations: larger genetic drift

(5) Causes and Mechanisms

Random (chance):

random sorting

population size bottleneck

individual fitness

Non-random:

individual fitness

environment

non-random sorting

genotypic fitness

Different processes cause different population patterns

(5) Directional Selection

Non-random sorting caused by a difference in genotype fitness that leads to an increasing or decreasing trend in a trait over time

(6) Stabilizing Selection

a type of natural selection that favors average, and selects against the extremes

Genotypic fitness data and phenotypic patterns can explain why a population DOESN’T change over time (random factors are always happening)

(7) Natural Selection

Directional and Stabilizing selection

(8) True or False: Natural selection and evolution are the same thing

False: evolution is change over time, natural selection is one of the ways evolution occurs

(8) evolution is a random process

False

(8) Any trait can evolve within any population

False: traits with no variation cannot be affected by genetic drift or natural selection

(8) Stronger and longer-lived individuals have higher fitness

False: The only trait that influences fitness are those that impact the lifetime reproductive output of an individual

(8) An individual can evolve in their lifetime

False: Evolution is measured at the population level and happen between generations. An individual cannot change their alleles, individuals cannot evolve.

(8) A trait will disappear if it is no longer used

False: using or not using a trait does not impact alleles

(8) Only beneficials alleles are passed on to offsprings

False: chromosomes contain beneficial, harmful and neutral alleles.

(8) Patterns of stability in traits over time indicate that nothing is happening

False: random selection is always happening. High genotypic fitness in the environment favors and they are most likely to survive and therefore pass on their traits.

(8) For natural selection to occur, environmental change must also occur

False: Natural selection does not require environmental changes.

Natural selection requires:

1. Heritable Variation

2. Transmission of Variation

3. Differential reproductive succes

(8) Evolution typically occurs when most members of a population gradually adjusts to a changing environment in their lifetime

False: Happens between populations not during a population

(8) Evolution occurs because organisms and species are forced to change or go extinct

False: A mutation occurs randomly, not based on needs. A mutation that could save a population might never appear

(8) Natural selection tries to make a species better over time

False: Natural selection is a passive mindless process that does not have a plan or goal

(8) Traits that are needed for survival are more likely to appear in a population

False: A mutation is not based on needs

(8) In a population of organisms, different mechanisms or processes are respondible for making traits appear or disappear. One process cannot do both.

False: same processes can increase or decrease traits

(8) The fitness of an individual can be determined without knowing anything about the environment in which it lives in

False: Fitness always depends on the environment

(8) Evolutionary Pressures typically cause more mutation to occur in a population experiencing environmental change

False: Pressure cannot cause a mutation or new variation to arise.

(8) Chance does not play a role in evolution

FALSE

(9) Sexual Dimorphism

Male and female species have different physical characters beyond their primary reproductive organs

Ex: Size, weapons, plumage, fancy ornaments

(9) Sexual Selection

Non-random

The process at which males and females are sorted differently

The pattern is the difference in phenotypic differences and the process is called sexual selection

(9) Ornaments and Behavior

males do not control access to resources

females choose mates

weapons and size

males do control access to resources

females do not choose mates

(9) Clustered Resources

male-male competition

(9) Dispersed Resources

Female Choice

(9) Natural Selection vs Sexual Selection

Natural and Sexual Selection

Heritable variation, non-random sorting based on environment

Natural Selection: Spans across entire lifespan, males and females sorted similarly, same phenotype for males and females

Sexual Selection: Only during when obtaining mates, females and males are sorted differently, different phenotypes for males and females

(9) How do females produce many offsprings with different phenotypes based on gender

Transcriptional regulatory proteins and gene regulatory switches