tf you mean this is the fourth exam

biology I hate you

character

observable feature - floral color

trait

particular form of a character- red flowers

gene

unit of inheritance segment of DNA that codes for a protein

true breeding genes

only form present over several generations 

heredity

passing on biological traits from one generation to the next 

variation

differences among individuals of the same species

gamete

mature sexual reproduction cell (sperm or egg) that unites with another cell to form a new organism

incomplete dominance

a genetic inheritance pattern where neither allele is completely dominant resulting in a blend- pink flowers

codominance

neither allele is masked making both visible

linkage

the tendency for genes located together or on the same chromosomes to be inherited together as a group during meiosis 

sex chromosomes

a type of chromosome that determines an organisms biological sex

autosomes

the 22 pairs of chromosomes in humans that are not sex chromosomes

sex linkage

traits or diseases caused by genes located on the sex chromosomes X or Y

test cross

a genetic cross used to determine the unknown genotype of an organism that shows a dominant phenotype

pedigree

a diagram that maps the inheritance of a trait or genetic condition through multiple generations of a family

independent assortment

alleles governing different traits assort independently of each other during meiosis- came from work with dihybrid crosses

gene segregation

the two alleles for a gene segregate during gamete formation and are rejoined atrandom one from each parents during fertilization 

gene pool

the stock of different genes in an interbreeding population

hardy Weinberg equilibrium

hypothetical state where a population allele and genotype frequencies remain the same from generation to generation no evolution 

gene flow

the transfer of genetic info from one population to another through the movement of individuals or their gametes like pollen

mutation

a change in a cells DNA sequence often caused by replication error or environmental damage from agents like radiation and chemicals 

genetic drift

the change in the frequency of alleles in a population from generation to generation due to random chance not natural selection 

founder effect

a type of genetic drift that occurs when a small group of individuals from a larger population establishes a new isolated colony

bottleneck effect

a phenomenon where a population size is drastically reduced by a catastrophic event such as nautral disaster leading to a significant loss of genetic diversity

assortative mating

the non random selection of partners based on similar traits such as physical social or behavioral characteristics

dissassortative mating

the reproductive paring of individuals with dissimilar traits leading to increased genetic variation and heterozygosity in the offspring 

stabilizing selection

a type of natural selection where an average phenotype is favored and extreme variations are selected against 

directional selection

a type of natural selection where one extreme phenotype is favored over others causing the average value of a trait in a population shift over time 

disruptive selection

an evolutionary process where extreme traits are favored over intermediate ones within a population

heterozygote advantage

a situation in genetics where two different allele for a gene (hetero) results in a higher fitness or survival rate compared to having two identical alleles 

microevolution

changes in trait/allele frequencies in a population over time

macroevolution

changes over deep time that lead to new species or groups of species

fitness

an organisms ability to survive and reproduce in its environment

the father of genetics

Gregor Mendel

law of segregation MENDEL

during gamete formation alleles separate so that each gamete receives only one allele for one gene- at fertilization the zygote gets one allele from each parent

independent assortment MENDEL

alleles governing different traits assort independently of each other during meiosis- one trait doesn’t effect the other (height and color) (independent)

rationale behind the classical testcross

cross unknown dominant genotype with a known recessive genotype 

how sex is determined

humans- 22 pairs of autosomes one pair sex XX female XY male
birds- comes from the egg
honeybees- females are diploid and males are haploid because they are formed from unfertilized eggs

what it means when genes are linked

located on the same chromosome and inherited together
crossing over occurs more between genes that are farther apart
not the same as sex linkage 
do not assort independently

Interpreting a pedigree

a consistent graphic representation of mating and offspring over multiple genreations for particular genetic trait such as albinism or hemophilia 

natural selection

produces evolutionary change when some individuals in a population with retina inherited traits produce more offspring than individuals lacking these traits 

importance of genetic variation

genetically based variation leads to evolutionary change

five assumptions of HWE

1. no mutation 2. no gene flow 3. random mating 4. large population
   5. no selection

Concept of fitness

genetic contribution of a genotype to the next generation relative to other genotypes combination of survival, mating success, and number of surviving offspring 

what maintains genetic diversity

mutation- only source of new alleles
genetic sexual recombination- crossing over, independent assortment, random fertilziation- more important source of variation than mutation 

Adaptation in evolutionary biology

the process where a species develops traits that improve its survival and reproduction in a specific environment over generations 

population genetics

study of genetic variation and its causes within populations relates to natural selection 

Genotypic relations with phenotypes

Do not uniquely determine phenotypes because observable traits are shaped by interactions between an individual’s genes and their environment 

Reason why survival of the fittest is bad

implies phsycial strength when the scientific meaning is reproductive fitness or the ability to pass on genes 

Why some deleterious alleles are maintained in populations

heterozygote advantage- heterozygotes may exhibit greater fitness than homozygotes 

How beak size correlated with evolution by natural selection

hypothesized that different beak shapes were related to food gathering

How industrial melanism can shift phenotypes within a population as a result of natural selection 

an evolutionary effect seen in various insects where dark pigmentation has evolved in an environment affected by industrial pollution 

intermediate fossils

posses some traits of their ancestors and some of their descendants

examples of fossil organisms

dinosaur- teeth, bony tail, claws
birds- short flight, feathers, wishbones

homologous structures

structures with different appearances and functions that are all derived from the same body part in a common ancestor 

homology of the bones

different functions same ancestral structure

vestigal structures

no function but resemble functional structures of ancestors

convergent evolution

the independent development of similar structures in organisms that are not directly related ex- marsupials and placental mammals

the study the Grant’s did

were from Princeton and studied medium ground finches on the Galapagos and it helped to show variation of beak depth 

Kettlewell’s discoveries

how pollution effects evolution in moths