BISC 1

Developed laws of inheritance; peas

• 1. Trait variation is due to alternative versions (alleles) of heritable factors (genes)
• 2. for each character an organism inherits 2 alleles
• 3. dominant alleles mask recessive alleles

two alleles for a heritable character segregate during gamete formation and end up in different gametes

different alleles of different loci sort independently

breeding "better" humans. forcibly sterilize people

2 sets of chromosomes

fruit fly experiments provided frist strong evidence genes are chromosomal

change phenotype and genotype

used bacteriophage to show that viral DNA can program cells

made x-ray diffraction images of DNA

used Franklin&Wilkins's x-ray images to deduce the double helix

heritable feature that varies among individuals

each variant for a character (purple color)

appearance or observable traits

genetic makeup

heterozygous for one character

heterozygous for two characters

when either-or classification is impossible b/c the characters vary in the population; a continuum

an additive effect of two or more genes on a single phenotypic character

developed classification system to reveal divine order of life; father of taxonomy

found diff fossils in diff strata and inferred extinction

found earth's features explained by processes currently operating; implied earth is >>>6000 yrs

evolution from a common ancestor, competition and sexual selection responsible for species change. vague ideas of transmutation

developed comprehensive theory of evolution that included discredited theory of inheritance of acquired characters

independently described an evolutionary system almost identical to Darwin's

• 1. members of a population often vary greatly in their traits
• 2. individuals inherit traits from parents
• 3. all species are capable of producing many more offspring than their environment can support
• 4. owned to lack of food or other resources many of these offspring don't survive

similarities due to common ancestry. homologous structures with very diff functions

historical remnants of traits important for ancestry (things that have reduced or have no function; due to ancestors who did have use for them, i.e. appendix in humans)

genetic code due to descent from common ancestors rather than individual creation

single-base substitutions caused by error in DNA synthesis or repair

caus addition/loss of amino acids, frame shifts or truncated proteins

duplications of short stretch of DNA caused by unequal crossovers during meiosis or strand slippage during DNA replication

breaks in 2 places, flips and reanneals

organism have more than 2 sets of chromosomes

changes in allele frequencies within populations which result from chance variation in individual survival and reproduction

consists of genetic addiction/subtractions resulting from movement of fertile individuals or gametes

selection against both extremes

selection against an extreme

selection against intermediate phenotype

natural selection for mating success can result in sexual dimorphism, sexually selected traits may be bad for survival

containing two complete sets of chromosomes, one from each parent

occurs when natural selection maintains two or more forms in population, leads to a state called balanced polymorphism

transforms one species into another

splitting of the gene pool, giving rise to one or more new species

• impede mating or hinder fertilization if mating occurs
• 1. habitat isolation
• 2. temporal isolation
• 3. behavioral isolation
• 4. mechanical isolation
• 5. gametic isolation

• prevent the hybrid zygote from developing into a viable fertile adult
• 1. reduced hybrid viability (genes of diff parent species may interact and impair hybrid development)
• 2. reduced hybrid fertility
• 3. hybrid breakdown

extra chromosome sets derived from one species

has chromosome sets derived from two diff species

the evolution of diversely adapted species from a common ancestor upon introduction to new environmental opportunities

evolutionary change at or above the species level

evolution within a species

changes in the relative growth rates of diff body parts

sexually mature adults with juvenile morphology

control body plans by controlling the developmental fate of groups of cells

the products of one class of homeotic genes, which provide positional info

many characters evolved for purposes other than those for which they are currently used

the evolutionary history of a species or group of related species

scientific system for classifying organisms

the science of naming and classifying living things

classification of organisms by their order of branching on an evolutionary tree

ancestor and all its descendents

ancestor and some of its descendents

descendents w/o common ancestor

analogous structures/molecular sequences that evolved independently

reconstruct phylogeny

genes are a single copy gene in the genome and are homologous between species

result from gene duplication, thus are found in more than one copy of the genome

• Kimura
• states much evolutionary change in genes and proteins has no effect on fitness and not influenced by darwinian selection

"how" questions about behavior

"why" questions about behavior

the study of behavior

sequence of unlearned behaviors that are largely unchangeable

selection for mating success, may oppose natural selection, may lead to sexual dimorphism

pollination, nutrient cycling, purification of air and water, detoxification and decomposition of wastes, moderation of weather extremes

breeding w/close relatives increases the chance the parents will share the same deleterious recessive alleles

• 1. fluctuations in population size over time
• 2. inbreeding
• 3. overlapping generations
• 4. unequal family sizes
• 5. unequal sex ratios

believed that resources can only support a limited population

natural theory of struggle among species

created Scala Natura, believed hierarchy of organisms was fixed

harmful allele fixation

organisms evolve structures that have similar (analogous) structures or functions in spite of their evolutionary ancestors being very dissimilar or unrelated.

• 1. random mating
• 2. infinitely large population
• 3. no natural selection
• 4. no genetic drift
• 5. no migration

features of different species that are similar in function but not necessarily in structure and which do not derive from a common ancestral feature and which evolved in response to a similar environmental challenge.

gene flow impeded by physical/geographic barrier, selection and drift lead to reproductive isolation

takes place in geographically overlapping populations, can occur through chromosome changes or through non-random mating