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ch 1, 9,10,14,15


the process by which the characteristics of individuals are passed to their offspring.


segments of DNA ranging from a few hundred to many thousands of nucleotides in length are the units of inheritance


a gene's physical location on a chromosome is called its


different versions of a gene at a locus


when both homologues have the same allele at a given locus


when homologues chromosomes have different alleles at a given locus


organisms that are heterozygous at a specific locus are called


when an organism's sperm fertilize its own eggs


when sperm from one organism fertilize eggs from a different organism


when an organism possesses a trait, such as purple flowers, that is always inherited unchanged by all of its offspring that are produced by self-fertilization

law of segregation

ex; the pairs of alleles on homologous chromosomes separate, or segregate, from each other during meiosis


the actual combination of alleles carried by an organism


the organisms traits (outward appearance,behavior, digestive enzymes, blood types, or any observable/ measurable feature) make up its ______

Punnett square method

a convenient way to predict the genotypes and phenotypes of offspring

test cross

this tests whether the organism with the dominant phenotype is homozygous or heterozygous

law of independent assortment

the independent inheritance of two or more traits


genes on the same chromosome tend to be inherited together (gene)

genetic recombination

the appearance of new combinations of alleles that were previously linked (explained by crossing over during meiosis )

sex chromosomes

in mammals, an individual's sex is determined by a special pair of chromosomes known as the,

X chromosomes

females have two identical sex chromosomes, called

Y chromosome

males have one X chromosome and one


the other chromosomes that occur in pairs that have identical appearance in both males and females


genes that are on one sex chromosome but not on the other are said to be

incomplete dominance

when the heterozygous phenotype is intermediate between the two homozygous phenotypes (hair texture)

multiple alleles

an individual can have at most two different alleles, a species may have _____ of many of its genes (human blood type, human diseases)


when heterozygotes express phenotypes of both of the homozygotes

polygenic inheritance

a form of inheritance in which the interaction of to or more genes contributes to a single phenotype (human height, weight, eye color, skin color... not split up into convenient easily defined categories)


single genes commonly have multiple phenotypic effects (SRY gene on the Y chromosome)


diagrams that show the genetic relationships among a set of related individuals


a person who is heterozygous for a recessive genetic trait (phenotypically healthy but can pass on the trait)

sickle-cell anemia

results from a mutation in the hemoglobin gene. A change in a single nucleotide results in a n incorrect amino acid at a crucial position in the hemoglobin molecule

huntington disease

a dominant disorder that causes a slow, progressive deterioration of parts of the brain, resulting in a loss of coordination, flailing movements, personality disturbances, and eventual death


caused by a recessive allele on the X chromosome that results in a deficiency in one of the proteins needed for blood clotting


during meiotic cell division, when a step is missed it results in gametes that have too many or too few chromosomes (effects number of sex chromosomes or autosomes)

Turner sydrome

When a female only has 1 X chromosome

trisomy X

triple x, 3 x chromosomes

Klinefelter syndrome


Jacob syndrome


trisomy 21/ down syndrome

an extra copy of chromosome 21


change over time in the characteristics of populations


the preserved remains or traces of organisms that died long ago


all the individuals of one species in a particular area

natural selection

individuals with advantageous traits survive the longest and leave the most offspring

homologous structures

when internal structures have the same evolutionary origin despite any differences in current function or appearance

vestigial structures

i.e molar teeth in bats that don't chew their food... traits that show up in animals that have no use for it

convergent evolution

natural selection causes non-homolgous structures that serve similar functions to resemble one another (birds and insects' wings)

analogous structures

these structures are typically very different in internal anatomy , because the parts are not derived from common ancestral structures (outwardly similar but non-homologous structures)

artificial selection

the breeding of domestic plants and animals to produce specific desirable features.

gene pool

the sum of all the genes in a population (in other words it consists of all the alleles of all the genes in all the individuals of a population)

allele frequency

the relative proportion of each allele

Hardy-Weinberg principle

under certain conditions, allele frequencies and genotype frequencies in a population will remain constant no matter how many generations pass (this population will not evolve)

equilibrium population

the term for the hypothetical non evolving population in which allele frequencies do not change so long as certain conditions are met

gene flow

there must be no movement of alleles into or out of the population


a population remains in evolutionary equilibrium only if there are no _____

genetic drift

the process by which chance events change allele frequencies

population bottleneck

a population is drastically reduced as a result of a natural catastrophe or over hunting

founder effect

occurs when isolated colonies are founded by a small number of organisms


when other organisms compete for scarce resources, most intense amongst organisms of the same species


when one species evolves a new feature or modifies an old one, the other typically evolves new adaptations in response


includes any situation in which one organism eats another

sexual selection

the special kind of selection that acts on traits that help an animal acquire a mate

directional selection

favors individuals with an extreme value of a trait and selects against both average individuals and individuals at the opposite extreme

stabilizing selection

favors individuals with the average value of a trait and selects against individuals with extreme values

disruptive selection

favors individuals at both extremes of a trait and selects against individuals with intermediate values


all matter on Earth consists of atoms of substances called _______


the smallest particle of an element that retains all the properties of that element


atoms may combine in specific ways to form assemblies called ______


the bodies of living things

organic molecules

contain a framework of carbon to which at least some hydrogen is bound


the smallest unit of life


cells of similar type combine to form structures known as


different tissues may combine to form

organ systems

a group of organs united by a common overall function are called


a collection of populations of different species that interact with one another makes up a


a community and the nonliving environment that surrounds it constitute an ____


the entire surface of Earth and the living things that dwell in and on it is called the


in a typical human body cell, how many chromosomes are there?

the chromosomes must be duplicated

what must happen before a cell can begin mitosis?


the centrosomes move away from each other and the nuclear envelope breaks up during which phase of mitosis?


the chromosomes line up in the center of the cell during which phase of mitosis?


the sister chromatids separate and begin moving toward opposite poles of the cell during which phase of mitosis?


the chromosomes arrive at the poles and the nuclear envelopes form during which phase of mitosis?


at the end of the mitotic (M) phase, the cytoplasm divides in a process called

when a cell divides via asexual reproduction

each daughter cell receives a nearly perfect copy of the parent cell's genetic information

4 haploid cells

meiosis starts with a single diploid cell and produces


a cell preparing to undergo meiosis duplicates its chromosomes during

during prophase I of meiosis,

homologous chromosomes stick together in pairs

the correct order of events during meiosis is

prophase I, metaphase I, anaphase I, telophase I, cytokinesis, meiosis II

prophase I

during meiosis, segments of insister chromatids can trade places. this recombination of maternal and paternal genetic material is a key feature of meiosis. during what phase of meiosis does recombination occur?

the S phase of interphase

during which phase of the eukaryotic cell cycle does DNA and chromosome replication occur?

reproductive tissues, gametes

Meiotic cell division occurs in the ________ and results in the production of __________


in a typical human body cell, how many sex chromosomes are there?


AA is a ___________ genotype

gene pool

all the genes in a population are that population's _______

the role of chance

genetic drift is a process base on ____

there is a change in the DNA sequence of a gene

a mutation occurs when

alleles that promote "tallness" will decrease in frequency

every few years a giant axe chops off the head of every person who is over 6 feet tall. how will this affect the human population?

genetic drift

modern travel along with migration reduces the probability of ________ having an effect on the evolution of humans

gene flow

the ease with which humans travel across the globe is likely to increase

metaphase I

homologous pairs of chromosomes are lined up independently of other such pairs during

nonsister chromatids of homologous chromosomes

crossing over, resulting in an increase in genetic variation, occurs between


in human gamete production there is an average of ______ crossover events per chromosome pair

prophase I

when does crossing over occur

ability to fuse haploid gametes to for a new individual

what is the most important for generating the most genetic variability in a species?


which phase of the cell cycle is most similar between a cell that will divide by mitosis and one that will divide my meiosis?

homologous chromosomes contain the same genes, but may contain different alleles

how are homologous chromosomes defined?

markers in your cells

research indicates that the best estimate of your age is from


the cells examined from the 2,400 people in this study were from


what damages cells and causes call aging

longer telomeres indicate younger cells

the researchers used strands of DNA located at the ends of chromosomes called telomeres to classify the cells they studied. what assumption did they make about telomeres?

longer in individuals who exercised regularly

the researchers found that telomeres were

exercised for an average of 30 minutes per day

the researcher showed that individuals who ______ had younger looking cells based on telomere measurements


fat, cigarette smoke, testosterone, UV light are all examples of


______ is a carcinogen that promotes colon cancer

genetic drift

the evolution of populations due to chance is

the frequency of the green allele will increase

if color is an inherited trait in beetles , and birds are more likely to eat brown beetles than green beetles,

has more effect on the evolution of a small population

in a population with brown and green alleles for color, genetic drift

gene flow causes the frequency of the green allele to increase

color is an inherited trait in beetles. if brown beetles move into a population from a nearby island, which statement is correct :

natural selection causes the frequency of the brown allele to increase

this is an example of genetic drift

gene flow causes the frequency of the brown allele to increase

gene flow causes the frequency of the green allele to increase

natural selection causes the frequency of the green allele to increase

Green beetles leave more offspring that brown beetles because they are better at finding food.

remember that color is an inherited trait in beetles. WOF is an example of natural selection?

Green beetles migrate out of the population, and brown beetles migrate into the population

A storm kills more green beetles than brown beetles by chance,

Green beetles and brown beetles always leave the same number of offspring.

Green beetles leave more offspring than brown beetles because are better at finding food.

Green beetles migrate out of the population.

natural selection

1. pesticide is applied to a population of insects. 2. some insects have a gene that makes them resistant to the pesticide. these insects survive. insects without the gene die. 3. the surviving insects reproduce. the frequency of resistant insects in the population increases.

mutations must occur to create new variety in the population

consider a population of bacteria that came from a single ancestor. because bacteria reproduce asexually, there should be no variation in this population, but that violates the first postulate of natural selection. how is it then that this population of bacteria can still evolve?

lamarck focused on genetic changes in an individual. darwin focused on genetic changes in a population

both lamarck and darwin proposed mechanisms to explain how evolution occurs. what was different about these mechanisms?


natural selection can at on a certain trait only if the trait is

the fish with green scales will become more common

fish in a local lake have a mixture of brown and green scales are are found throughout the lake. over a five-year period, the lake develops more plant growth and an exotic predatory frog is introduced. what change would you expect to see in the original fish population?

natural selection acts on individuals

which of the following is true about natural selection?

gene flow

from an evolutionary point of view, what important process occurs when a young male baboon leaves the troop that he was born in to join another troop?

if more offspring caring an allele are created, the frequency of the allele increases.

why is natural selection based entirely on reproductive success?

a mutation resulting in a heat-resistant enzyme in a bacterium living in a hot spring

Which trait is the BEST example of an adaptation?

a shorter neck in a giraffe that lives in an area with many rival males and tall trees
a new mutation that confers Tay-Sachs disease in humans
a mutation resulting in weak branches in a species of tree that lives in windy regions
a mutation resulting in a heat-resistant enzyme in a bacterium living in a hot spring
a longer tongue in an insect-eating mammal that feeds on insects that live in shallow burrows

natural selection

a patient has an infection of Streptococcus bacteria. she takes azithromycin, which kills 99 percent of a bacteria population. all surviving bacteria are resistant to azithromycin. what has occurred in this bacterial population ?

reproductive success

in the common phrase, "survival of the fittest," what determines how fit an individual is?

inbreeding (if the member of the population mater only with the closest individual, the population can quickly become inbred. this can happen in a predator pack or in pockets of plants in a larger population)

WOF is a result of nonrandom mating within a population?

gene flow
genetic drift

the population needs to be small

what condition is necessary for genetic drift to have a significant effect on a population?

one that increases the frequency of successful reproduction

WOF mutations would increase evolutionary fitness?

one that removes other alleles from the population
one that increases the life span of the organism
one that increases the frequency of successful reproduction
one that attracts more potential mates without increasing the frequency of reproduction
one that increases the birth weight of offspring while decreasing their number


you wish to research how genetics determine color of deer mice. how many genes should you focus on?

to allow for faster growth

the three-spine stickleback typically lacks armor in fresh water. why?

genotype determines phenotype

WOF is true?

Phenotype determines genotype.
Genotype and phenotype are the same thing.
Genotype determines phenotype.
Genotype and phenotype are not related.

in a monastery

Mendel worked

all of the above

how do mutations affect an organism?

they may cause the development of a disease-causing allele
they may cause the development of a more beneficial allele
they, in some cases, may have no noticeable affect
all of the above


DNA replication occurs at an unbelievably fast rate. once replication is complete, we can expect to find a _____ number of mistakes.

her egg cells

a female that is planning to become pregnant is concerned about her exposure to environmental mutagens which may have caused DNA mutations. In order for these mutations to become heritable, they must affect:

both parents are heterozygous for both genes

a phenotypic ratio of 9:3:3:1 in the offspring of a cross indicates that

a G paired with a T

WOF would indicate a base pairing mutation in DNA?

an A paired with a T
a C paired with a G
a G paired with a T
all of the above are improper base pairs


In people, a dimpled chin is an autosomal dominant trait. Many famous celebrities, such as John Travolta and Michael and Kirk Douglas, have this condition. Assume that the wrestler and actor Hulk Hogan is homozygous for the dimpled chin, and he married a woman with a round chin. They had two children, Brooke and Nick. What proportion of their female progeny (such as Brooke Hogan) will show the trait?

75% dominant: 25% recessive

What is the ratio of phenotypes in the offspring produced by the cross Aa x Aa? Assume complete dominance for the trait.


In crossing a homozygous recessive with a heterozygote, what is the chance of getting a homozygous recessive phenotype in the F1 generation?

anaphase I

During which phase of the cell cycle does the Law of Segregation of Alleles occur?

linkage (linked genes do not assort independently)

Which of the following represents an exception to the law of independent assortment?

crossing over

when genes are linked, a few of the recombinant genotypes still occur in the offspring because of:

both parents are heterozygous for the disease allele

two healthy parents give birth to a child with cystic fibrosis, a recessive disorder. what can we say about both parents?

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