Biology final

define natural selection

A process in which individuals with certain (beneficial) inherited traits are more likely to survive and reproduce than are individuals that do not have those traits.

If a population IS EVOLVING, what are the agents

-Genetic Drift, Small population. -Nonrandom mating. -mutation. -Gene Flow/ Migration. -Natural Selection.

who are the people that influenced Darwin

-Lamarck: he thought that Organisms pass traits acquired during their lifetimes to their offspring and that organisms endowed with a vital force that drove them to change toward greater complexity and perfection. -Malthus: he thought that conflict between population size and food supply generates famine, disease, and war which alters population growth, which is known as a struggle for existence. -Lyell: o Earth did not originate in present form, it was a slow pace of geologic processes that are still occurring today which meant that the Earth is very old. This theory helped Darwin believe that his ideas could be possible because there was more time for spices to develop and change over a longer period of time.

what are the 5 Hardy-Weinberg conditions

1)Population size is large

What does Differential Reproductive Success include as a condition for natural selection to occur

1. Better adapted individuals will more likely to survive, reproduce and pass their traits on to the next generation.

List the 5 conditions that must be present for a population to be in genetic equilibrium.

1. Population is large. 2. Mating is random. 3. There are no mutations. 4. There is no gene flow. 5. There is no natural selection.

The Conditions for Genetic Equilibrium:

1. Population size is large 2. Random mating 3. No mutations 4. No migration or gene flow 5. No selection When all of these conditions are met, the population would be in Hardy Weinberg Equilibrium because the frequencies would not change over time.

what are the 4 conditions of Darwin's theory of natural selection as mechanism for evolution

1. variation

the two genes related to eye development share more than _____% of their nucleotides, indicating the gene for eye development is very highly conserved within animals.

75

Darwin's theory of Natural selection as a mechanism for evolution is described as ...

A process in which individuals with certain (beneficial) inherited traits are more likely to survive and reproduce than are individuals that do not have those traits.

what did Thomas Malthus state

Conflict between population size and food supply generates famine, disease, and war which alters population growth. A struggle for existence.

All living species use_____ to store information

DNA

What does limits on population growth include as a condition for natural selection to occur

Due to limited resources and other constraints, not all offspring survive to reproduce.

what does fitness measure

Fitness is a measure of reproductive success, the relative likelihood of an individual contributing fertile offspring to the future generations.

what are evidence of evolutionary change

Fossil records, biogeography and observation of artificial selection in plants and animals.

_________ happens in island populations.

Founder effect

define homologies

Fundamental similarity due to descent from a recent common ancestor

What term do we use to describe a population that is NOT undergoing evolutionary change?

Genetic Equilibrium. This is when the population is stable and unchanging, allele and genotype frequencies do not change from generation to generation. This means that the population is not undergoing evolution.

__________ can be used to test whether evolution is occurring in a population. It describes mathematically that in the absence of outside forces, allele and genotype frequencies do not change from generation to generation, the population is NOT undergoing evolution. This results in a stable unchanging population called genetic equilibrium.

Hardy-Weinberg Principle/equation

what happened on Darwins voyage across the south american coast

He observed the organisms of the Galapagos, while different, resembled those of S.A. more then the rest of the world. Spatial similarities and differences.

who was Jean Baptiste de Lamarck and how did he influence darwin

He was a French scientist that believed that "Organisms pass traits acquired during their lifetimes to their offspring and that organisms endowed with a vital force that drove them to change toward greater complexity and perfection.

who was Thomas Malthus and how did he influence Darwin

He was an English Clergyman and economists thought that thought "conflict between population size and food supply generates famine, disease, and war which alters population growth, which is known as a struggle for existence

define homplasy

Homoplastic features demonstrate that organisms with separate distant ancestries may adapt in similar ways to similar environments; convergent evolution

What does variation include as a condition for natural selection to occur

The individuals of a population exhibit variation. Some of this variation is heritable. Genetic variation is the raw material for evolution.

True or False: Evolution can occur over just a few generations.

True

Darwin believed that there had to be the following four conditions for his theory to be accurate. What are those conditions

Variation - the individuals of a population exhibit variation. Some of this variation is heritable. Genetic variation is the raw material for evolution. overproduction- in every generation each species has the capacity to produce more offspring than can survive. limits on population growth- due to limited resources (and other constraints) not all offspring survive to reproduce. Differential reproductive success- better adapted individuals will more likely to survive, reproduce, and pass their traits on to the next generation.

what are the conditions for natural selection to occur

Variation, Overproduction, Limits on population Growth, Differential Reproductive success.

Struggle for existence, population changes, and inheritable traits over time and spatial similarities/differences...species appear to _____ to changes in the environment

adapt

Individuals moving into or out of a population take their _____ with them, changing the allele frequency of the population.

alleles

who was Charles Lyell and how did he influence Darwin

an English geologist that believed the Earth did not originate in present form, it was a slow pace of geologic processes that are still occurring today which meant that the Earth is very old. This theory helped Darwin believe that his ideas could be possible because there was more time for spices to develop and change over a longer period of time.

Phylogenies represent ________

an evolutionary tree of life

define mutation

any change in the DNA sequence

1. Why do we study evolution at the population level and not the individual level?

because individuals do not evolve, populations do. The evolutionary impact is only apparent in the genetic changes in a population over time.

define differential reproductive success

better adapted individuals will more likely to survive, reproduce, and pass their traits on to the next generation.

define adaptation

change in allele frequencies of genes over time

what is genetic drift

changes in allelic frequency due to random chance (unrelated to fitness or selection). Genetic drift only happens in small populations. It can result in either loss or fixation of an allele regardless if beneficial, harmful or neutral. Genetic Drift decreases genetic variation within a population.

genetic drift _____ genetic variation

decrease

define limits on population growth

due to limited resources (and other constraints) not all offspring survive to reproduce.

Similarities in cells at the molecular level indicate that living species _____ from a common ancestor or interrelated group of common ancestors

evolved

what does the eyeless gene control

eye developement in fruit flies

what does the pax6 gene control

eye developement in mice

define stabilizing selection

favors intermediate phenotypes.

define homplastic features

features with similar functions that evolved independently in distantly related organisms

evolution can occur over _____ generations and is most commonly expressed as an _____

few

Darwin suggested that organisms that survive and reproduce successfully have genetic traits aiding survival and reproduction. These traits enhance an organism's _____

fitness

what is a population

group of individuals of the same species that live in an area (environment) together and can interbreed with one another. Some species occupy a wide geographic range and are divided into populations.

what did Charles Darwin do

identified natural selection as a mechanism of evolution and wrote "the origin of species"

define overproduction

in every generation each species has the capacity to produce more offspring than can survive.

define gene pool

includes all the alleles for all the loci present in the population

what is gene pool

includes all the alleles for all the loci present in the population. Individuals don't evolve, populations do.

gene flow _____ genetic variability

increases

What are FALSE statements about evolution?

individuals evolve during their lifetime. natural selection is the sole mechanism of evolutionary change. evolution is limited to speciation.

define vestigial structure

remnants of more developed structures that were present and functional in presumed ancestors.

Darwin suggested that organisms who survive and reproduce successfully have traits that aid in this process. These traits are said to enhance the fitness of the organism. A popular saying in biology is, "Survival of the Fittest", but really fittest is referring to fitness. What does this term "fitness" measure?

reproductive success

what is NOT one of Darwins assumptions of Natural Selection as a mechanism for evolution?

resources are infinite

define directional selection

shifts the overall makeup of the population by acting against individuals at one of the phenotypic extremes.

define homologous features

similar features with different functions evolved from the same structure in a common ancestor.

define evolution

the accumulation of inherited (genetic) changes within populations over generations

define variation

the individuals of a population exhibit variation. Some of this variation is heritable. Genetic variation is the raw material for evolution

define gene flow

the movement of alleles between two populations.

define genetic equilibrium

the population is not undergoing evolution; allele and genotype frequencies do not change from generation to generation.

what is genetic equilibrium

the population is not undergoing evolution; allele and genotype frequencies do not change from generation to generation. Genetic equilibrium is rare in nature.

define population genetics

the study of genetic variability within a population and the forces that act on it.

what is population genetics

the study of genetic variability within a population and the forces that act on it.

what did fossil records show

they link early extinct species with species that are living today. they are the imprints or remains of organisms that lived in the past. Document differences between past and present organisms and reveal that many species have become extinct. Multicellular (complex) organisms are in younger rocks, unicellular (simple) organisms are in older rocks. Fossil records reveals the historical sequence in which organisms have evolved.

how does Phylogenies represent an evolutionary tree of life

through characteristics (i.e. homologies) being traced through many lineages of life

what is inheritance

traits that are being passed down from one generation to the next.

define founder effect

type of genetic drift that is similar to a bottleneck and is caused when small subpopulations become isolated from the larger population

define disruptive selection

typically occurs when environmental conditions vary in a way that favors individuals at both ends of a phenotypic range over individuals with intermediate phenotypes.

The Hardy-Weinberg equation can be used to test what

whether evolution is occurring in a population.

For alleles to have equal chance of being passed down from one generation to the next, mating _____ the population must be random

within

what is modern synthesis

· Combines Darwin's ideas with the units of evolutionary change. · Integration between the units of evolution (genes) and the mechanism of evolution (natural selection) a synthesis. This explains Darwin's observation of variation in terms of mutation. Modern synthesis also represents a unification of several branches of biology that previously had little in common.

what does the hardy Weinberg equation describe

· a population that is in genetic equilibrium (i.e. not evolving).

What is the criteria for a population to be in "genetic equilibrium"

· large population · random mating · no mutations · no gene flow · no selection for any trait

what did Charles Lyell state

- the Earth did not originate in present form

define macroevolution

(big changes)

define microevolution

(small changes)

what did Charles Darwin state

- All species that exist today,

of animal husbandry

- Breeders and farmers could develop many varieties of domesticated animals in a few generations (artificial selection).

what is the evidence for evolution

- Fossil Record

who were the influencers for Darwin's origin of species

- Jean-Baptiste de Lamarck

define the The Voyage of the HMS Beagle

- Observation: The organisms of the Galapagos, while different, resembled those of S.A. more than the rest of the world. ...spatial similarities and differences.

what did Jean-Baptiste de Lamarck state

- Organisms pass traits acquired during their lifetimes to their offspring.

define selective breeding/artificial selection

- Programs and procedures designed to modify traits in domesticated species

what are the 5 mechanisms for evolution

- Small population; Genetic drift

what is the founder effect

- a type of genetic drift. -It has a similar affect as bottleneck. - It reduces genetic variability due to small population size. -It is caused when a small subpopulations become isolated from the larger population. - Alleles in the founders of subpopulation are disproportionately represented in subsequent generations.

populations can vary in what 3 things

- genotype

what is a scientific theory

- popularly, a mere conjecture, or guess

the evolution of organisms is constrained in what 4 ways

- selection can act only on existing variations

Natural selection can affect the distribution of phenotypes in a population in what 3 ways

- stabilizing selection

what are the types of selection

- stabilizing. - directional. - disruptive.

What does overproduction include as a condition for natural selection to occur

In every generation each species has the capacity to produce more offspring than can survive.

Inheritance work of Gregor Mendel, Darwin did not understand the process of__________________. once Darwin understood, Mendel's work began to answer his questions.

Inheritance

_________ is the only one that leads to adaptive evolution. Organisms become adapted to their environment.

Natural selection

Why does natural selection not lead to the "perfect" organism?

Natural selection cannot fashion perfect organisms. The evolution of organisms is constrained. 1. Selection can act only on existing variations. New advantageous alleles do not arise on demand. 2. Evolution is limited by historical constraints. Evolution co-opts existing structures and adapts them to new situations. 3. Adaptations are often compromises. The same structure often performs many functions. 4. Chance, natural selection, and the environment interact. Environments often change unpredictably.

define adaptive evolution

Natural selection is the only mechanism that leads to adaptive evolution - that results in a better fit between organisms and their environment

_____ mating can give an advantage to certain alleles over other alleles, increasing their relative frequency over time.

Non-random

what does the Hardy-Weinberg principle state

States that in the absence of evolution, the allele and genotype frequencies of a sexually reproducing population can be described mathematically

define biogeography

Study of the geographical distribution of extinct and modern species

what is biogeography

The study of the geographical distribution of extinct and modern species. Isolated continents and island groups have evolved their own distinct plant and animal communities.

define adaptation

a (an evolutionary) modification (a trait) that improves the chances of survival and reproductive success in a given environment.

define population

a group of individuals of the same species that occupy the same environment (time and space) and can interbreed with one another.

define fitness

a measure of reproductive success; the relative likelihood of an individual contributing fertile offspring to the future generations

For genetic equilibrium to occur, there would be no selection for what

a particular trait

define bottlenecks

a type of genetic drift that reduces population size

what are examples of homoplasy

aardvark/ giant anteater / pangolin

what are Darwins assumptions of natural selection as a mechanism for evolution

individuals within a population are genetically variable. overproduction of offspring. better adapted individuals are more likely to contribute their traits to the next generation.

define genetic drift

is changes in allelic frequency due to random chance (unrelated to fitness or selection)

evolution ______ _____ limited to speciation that may only occur over very long periods of time

is not

What is the Hardy-Weinberg principle? Specifically, what does the mathematical equation help scientists do?

it states that the population genetics is the study of genetic variability within a population and the forces that act on it. The mathematical equation helps scientists test whether evolution is occulting in a population.

Scientists have shown that when the mouse Pax6 gene was expressed in legs of fruit flies, eyes developed on their _____

legs

bottlenecks cause a _____ in genetic variation

loss

What kept darwin from publishing his book

many people only believe one way of how things could have happened. Darwin was scared to share his theory because he didn't think anyone would believe him.

What provides the ultimate source of variation among individuals within a population? Example: You look around the room and notice people in the room have different hair colors. We are the same 'species', but we are a very diverse group. What provides this observed variation.

mutation

what are the source of variation

mutation

Darwin's theory of _____ _____ as a mechanism for evolution

natural selection

Over generations, changes may accumulate in separate populations to produce what 3 things

new species, new adaptations, or allele frequencies.

What is homoplasy?

o Distantly related organisms evolve in similar ways due to exposure to similar environmental constraints (convergent evolution).

Macroevolution

o Significant evolutionary changes in populations that result in new species; speciation.

What is evolution

o The accumulation of inherited changes within populations over generations. o Evolution can occur over a few generations and is most commonly expressed as an adaptation to changing environment or the change in allele frequencies of genes over time. o Evolution does not refer to changes that occur in an individual within its own lifetime. Evolution Is not limited to speciation that may only occur over very long periods of time.

what is homology

o it is Similarity that result from shared ancestry. o Can be anatomical (vertebrate forelimb) § vestigial structures= remnants from ancestors o developmental (embryonic development) o molecular (similar DNA sequences i.e. genes)

what does adaptation mean

o it is a term used to describe a trait that improves the chances of survival and reproduction. o it is a modification that improves the changes of survival and reproductive success in a given environment. o it increases an organisms fitness. · Example: Cactus plants are well adapted to living in dry conditions (spines, thick waxy cuticle, shallow roots, grow quickly, store water, etc.)

what is microevolution

o small changes. o Changes in allele or genotype frequencies that occur in a population over a few generations. o Changes in allele frequencies from one generation to the next or adaptations may result.

Then what makes evolutionary changes and genetic equilibrium mechanisms different?

one increases genetic variability and one decreases it.

genetic equilibrium is _____ in nature

rare

founder effect _____ genetic variability

reduces