bio exam review 4

A unit of heredity which is transferred from a parent to an offspring; offspring inherits one set of chromosomes from each parent, thus two sets of genes.

Each of the two copies of an inherited gene.

a specific characteristic of an individual (ex: hair color)

Pair of chromosomes from mother results in one gene.

Pair of chromosomes from father results in one gene.

Chromosome pairs of approximately the same length, centromere position, and staining pattern; one homologous chromosome is inherited from each parent (ex: two copies of Chromosome 1 within each cell)

A dominant trait masks the effect of a recessive trait when the individual carries both the dominant and recessive versions of the trait (purple flowers were dominant over white flowers in Mendel’s pea plant experiment)

An allele with a phenotypic effect that is masked by the presence of a dominant allele (white plants were a result of the recessive gene in Mendel’s pea plant experiment)

Traits that are determined by the instructions a person carries on one singular gene (color blindness, albinism, cystic fibrosis). Most human traits are the result of multiple genes.

the outward appearance of an individual (ex: hair color, eye color, height)

An organism’s genetic composition for a particular trait (ex: homozygous for the recessive allele for albinism)

A way to explore the potential genotype of an individual based on the genetics of its parents

Used to determine the possible outcomes of a cross between two individuals

A mother that is homozygous for the recessive gene of albinism (mm) is crossed with a father who is homozygous for the dominant gene of pigment (MM). Their offspring will always have the gene combination of heterozygous Mm, making the phenotype a regular pigment

A mother that is heterozygous for the gene of albinism (Mm) is crossed with a father who is also heterozygous for the gene of albinism (Mm). Their offspring has a 25% chance of being homozygous for the dominant trait of pigment (MM), a 50% chance of being heterozygous and displaying the trait of pigment (Mm), and a 25% chance of being homozygous for the recessive gene of albinism (mm).

A tool to document a trait of interest across multiple generations of family members; may be used to determine if a trait is dominant/recessive or sex-linked/autosomal.

Traits that are controlled by the genes on the sex chromosomes (ex: red-green colorblindness and hemophilia)

The phenotype of a heterozygote is intermediate between the phenotype of the two homozygotes (FH allele and LDL receptors in humans). In snapdragons, a white-flowered homozygous mother snapdragon (CwCw) and a red-flowered homozygous father snapdragon (CrCr) will produce 100% of heterozygous offspring (CwCr) with the phenotype of pink flowers.

A heterozygous individual shows features of both alleles and neither allele masks the physical presence of the other. In chickens, when a mother with black feathers is crossed with a father with white feathers, the offspring will have both black and white feathers.

The result of multiple allelism (IA, IB, and i) resulting in 6 genotypes (IAIA, IAi, IBIB, Ibi, IAIB, and ii), and 4 phenotypes (A, B, AB, or O).

Can receive A+, A-, O+, and O-

Can receive A- and O-

Can receive B+, B-, O+, and O-

Can receive B- and O-

Universal recipient

Can receive AB-, A-, B-, and O-

Can receive O+ and O-

Can receive O-

Chemicals on the surface of some cells that act as “signposts” in the body’s immune system; tell the immune system whether the cell belongs in the body

Immune system molecules in the bloodstream that attack foreign invaders

Traits that are influenced by many different, continuously varying genes (Ex: height)

When the effects of the alleles of multiple genes all contribute to the ultimate phenotype.

When one gene influences multiple unrelated traits. The allele for sickle-cell disease is pleiotropic, influencing multiple traits (causes red blood cells to form an unusual, sickled shape, but also provides resistance to malaria)

Genes that are physically close to each other on the same chromosome; the alleles of these linked genes will be inherited together as a pair often (Ex: red hair and freckles)

change of allele frequencies in a population

A mechanism of evolution that occurs when, for a heritable variation of a trait, individuals with one version of the trait have greater reproductive success than individuals with the different version of the trait

The fossil record, biogeography, comparative anatomy and embryology, molecular biology, and laboratory and field tests.

Results in evolution; for example, the proportion of orange fur pigment alleles and the proportion of white fur pigment alleles in a tiger population will change gradually over time.

Dogs are not descended from the gray wolf species as previously hypothesized.

The set of all genes in any population (usually a particular species); includes genes that are expressed as well as those that are not.

An alteration of the base-pair sequence in the DNA of an individual’s gamete-producing cells that changes an allele’s frequency (consequence of altering a DNA sequence). Only mutations that affect reproductive cells can be passed to offspring (Marfan syndrome).

A random change in allele frequencies unrelated to any allele’s influence on reproductive success. A pair of heterozygous cats (Ss) could have two offspring that are homozygous recessive (ss) causing an increase in the proportion of recessive alleles in the population

a change in allele frequencies caused by individuals moving in or out of the population.

When an allele’s frequency in a population reaches 100%.

When the founding members of a new population have different allele frequencies than the original source population. For example, an autosomal recessive trait for which the recessive trait is at very low frequency. Among a group of individuals leaving the population and founding a new, isolated population, the recessive alleles may be more common (polydactyly among the Amish population of Pennsylvania)

When famine, disease, or rapid environmental change causes the deaths of a large random proportion of the population, and the surviving individuals have different allele frequencies than the original population

the process by which natural selection favors traits, such as ornaments or fighting behaviors, that give an advantage to individuals of one sex in attracting mating partners (brightly colored feathers of male peacocks).

The transmission of traits from parents to offspring via genetic information

A situation in which some individuals have greater reproductive success than other individuals in a population. This occurs when there are more organisms born than can survive, organisms are continually struggling for existence, and when some organisms are more likely than others to survive and reproduce (ex: the runt of a litter).

A measure of reproductive output of an individual with a particular phenotype relative to the reproductive output of individuals of the same species with alternative phenotypes; depends on the environment (ex: the allele for white colored fur will be more prevalent in a lighter habitat and the allele for brown colored fur will be more prevalent in a darker habitat).

Individuals with the greatest reproductive output that are the most fit in any population.

individuals with one extreme from the range of variation in the population have higher fitness. For example, farmers select against turkeys with smaller breasts because they are less valuable (average breast size will increase over time due to selection).

individuals with intermediate phenotypes are most fit. For example, selective pressure (babies with low weights are more vulnerable to complications and babies with high birth weights are more vulnerable to complications) results in a stable average birth weight

individuals with intermediate phenotypes have the lowest fitness. For example, selective pressure (medium sized fish get outcompeted for territory by larger fish, and small fish can sneak in and fertilize eggs before being detected) will result in higher numbers of incredibly small and incredibly large fish over time.

includes the preserved remains of organisms from long ago and can use radiometric dating to measure the age of a fossil

 the study of distribution patterns of living organisms around the world

shared embryological stages indicate common ancestry

all living organisms share the same genetic code, and related individuals share a greater proportion of their DNA than unrelated individuals (ex: humans and chimpanzees).

body structures in different organisms that, although they may have been modified overtime to serve different functions in different species, are derived through inheritance from a common evolutionary ancestor (ex: bones in human arm, leg of horse, wing of bat, and fin of porpoise).

a structure that was once useful to the organism but has lost its function over time (ex: molars in bats that now consume an entirely liquid diet).

when features of organisms not closely related come to resemble each other because of similar selective forces (wings of dragonfly and bat).

the process by which organisms become better matched to their environment and to the specific features that make the organism more fit (ex: quills on porcupines minimize the danger of predation on species)

The longer two species have been evolving separately, the greater the number of genetic differences they accumulate

differential reproductive success is influenced by humans; typically, with the goal of increasing the prevalence of a desired trait among a population.

over time, natural selection has led to an increase in antibiotic-resistance alleles, and humans are increasingly at risk from untreatable bacterial infections.

41.9% of Americans are considered obese.

obesity is associated with Type 2 diabetes, heart disease, and certain cancers.

body mass index; weight/height^2

BMI is not an accurate prediction of health (professional athletes can be considered obese). The ratio of hips to waist is a better measure.

process of maintaining a stable internal environment.

The thin ideal is relatively new. In former societies, being fat meant you were wealthy and had power.

 sequence in which each number is the sum of the two previous numbers (1+1=2, 1+2+3, 2+3=5, 3+5=8)

  phi= 1.6180339887…; appears in nature and in “pleasing structures”

symmetry based on the golden ratio makes faces “more attractive”. Makeup is used to achieve this golden ratio of symmetry.

in humans, power and intelligence are quality genes.

hormone that makes you hungry when your stomach is empty

hormone that stops hunger when energy reserves are good

  hormone that stops hunger when blood sugar is good.

hormone that makes you hungry when your mind thinks you should be hungry.

  Ideal weight for “health” is 10% above the US health average. Fit and fat live longer than thin and sedentary (1/2 the death rate).

 cutting out a few hundred calories a day can be beneficial for weight loss, but anything more can be harmful. Consuming less than 2,100 calories per day leads to nutrient deficiencies and can cause faulty memory, clumsiness, and hostility.