Bio 114 Final

science

the process of identifying patterns and asking questions that help understand those patterns; the process of disproving hypotheses

hypothesis

specific, testable, rejectable statements

theory

an umbrella term for several related phenomena; has a tremendous amount of evidence to support the concept and the patterns it describes

pattern

a part of a theory; the general observations of repetition one sees within a system (like observations)

process

a part of a theory; the mechanism or way in which the pattern occurs (there many be multiple processes involved in a pattern

proximate

a part of a process; that which occurs in the short-term (usually measured in fractions of lifetimes)

ultimate

a part of a process; a longer timeframe (most of a lifetime or more)

cell theory

all organisms are made of cells, and all cells are derived from pre-existing cells; life is continuous; understanding how an organism works is a function of understanding the structure and function of its cells; all cells can be traced back to on common ancestral cell

cell

a naturally occurring compartment bound by a thin, flexible plasma membrane, and contains chemicals in an aqueous solution that perform life functions

evolutionary theory

all life is the product of evolutionary processes; evolution explains variation; all species are related to each other through common ancestry

evolution

the heritable change in population over time; the primary mechanism of evolution is natural selection; the change in genetic (allelic) frequency over time

biological hierarchy

atoms, molecules, organelles, cells, tissues, organs and organ systems, organisms, populations, communities, ecosystems, biosphere

organisms

individuals; typically a collection of organ systems, but can also be single-celled; acted on by natural selection

population

collections of individuals of the same species; typically interbreeding; evolutionary change effects the whole population

community

collection of populations of different species living together in the same area

ecosystem

community plus abiotic factors

biome

a collection of very similar ecosystems, largely bounded by global influences like weather and climate

biosphere

all the ecosystems or biomes put together; all that gets in is sunlight and all that gets out is heat energy

emergent property

collection of the units at one level takes on a trait that is greater than the sum of the parts

Aristotle’s Great Chain of Being

all species are organized into a sequence based on increased size and complexity, with humans at the top (from before we knew about evolution)

Jean-Baptiste de Lamarck

first to state that species have changed throughout time; species change through time via acquired characteristic (disproved by Darwin)

acquired characteristics

belief that individuals change as a result of environmental pressures and then pass those changed traits to offspring

components of origin of species by natural selection (3)

all species have a common ancestor; all species show changes in characteristics through time; all species show changes in characteristics in different environments

requirements of natural selection (4)

trait variation in a population; heritability; differential survival; differential reproduction

fitness

the number of viable offspring produced in a lifetime

adaptation

a heritable trait that increases the relative fitness of individuals having the trait; a process by which individuals within a population acquire traits that increase their relative fitness; a phenotype that is selected for within a population

selecting agent

that which drives the evolutionary process

artificial selection

the same as natural selection, but the selecting agents are humans; resulting desirable traits do not necessarily allow the individuals to survive and reproduce more offspring in the wild

conclusions of evolutionary theory (3)

species are related; species (and species diversity) change over time; evolution should be able to be seen in the short-term

macroevolution

the change of one major taxonomic group into another (e.g., fish to amphibians to reptiles), or the creation/extinction of species

microevolution

change in a population over generations that helps to separate population from each other genetically; accumulation of microevolution over a long period may result in the creation of new species (macroevolution)

homology

similar traits in separate species due to a shared common ancestor

genetic homology

similar gene sequences between individuals of different species

development homology

similarities in morphology of embryos of different species

structural homology

similarities in structure of body parts of different species

vestigial traits

structures in organisms commonly found in the species that serve little or no function

atavism

a vestigial trait found in very few individuals within a species

evolutionary trends (5)

an increase in multicellularity; increase in complexity; increase in ways to capture energy for use; increase in ways to deal with the environment; an increase in diversity

contrivance

an adaptation in an organism, where the adaptation exists as a result of the modification of the original (or previous) adaptation in an ancestor; an adaptation that has been evolutionarily modified during the course of its inheritance from the ancestral condition (exaptation)

exaptation (pre-adaptation)

a trait that was adaptive under a prior set of conditions and later provides the initial stage for evolution of a new adaptation (contrivance) under a new set of conditions (in descendants); an adaptation possessed by an ancestor that changes over evolutionary time and exists as an adaptation in the descendant (contrivance)

vestigial trait

a trait the entire species has that is no longer used or has no use in the present environment, but was likely an adaptation for an ancestor

atavism

a trait possessed by only a few members of the population that is no longer used or has no use in the present environment, but was likely an adaptation for an ancestor

homoplasy

organisms have traits in common, but do not have a common ancestor that provided them with those traits (most common type is convergent evolution)

convergent evolution

the most common type of homoplasy; the independent natural selection of similar traits by unrelated individuals

phenotype

measurable traits of an organism

genotype

genes that code for traits; all of the alleles of all the genes within an individual or may refer to a specific set of alleles of a set of genes under study

genome

all of the hereditary information within an individual (includes non-gene stretches of DNA)

gene pool

all the alleles of all the genes within a population

genes

section of DNA found on chromosomes that encodes for a polypeptide, which causes a trait or regulates the activity of other genes

locus (loci)

the location(s) of a gene on a chromosome; in a population the locus for a specific genes is considered to be the same throughout

alleles

particular versions of a gene that occur at the same locus on homologous chromosomes

chromosome

a structure made of DNA and associated proteins that carries genes

ploidy

the number of chromosomes in a set and the number of sets of chromosomes a cell contains

haploid

one copy of a chromosome; 1n

diploid

a homologous pair of chromosomes; 2n

dominance

one allele of a gene is expressed in the phenotype in the presence of another allele at the same locus in diploid individuals

meiosis

the process of the production of gametes produced by individuals by halving the number of chromosomes and placing them into gametic cells; includes both meiosis I and meiosis II which help increase variation

sister chromatids

pairs of chromosomes

tetrad

set of four chromatids

non-sister chromatids

chromatids from the parental homologs (one maternal, one paternal)

first area of variation (meiosis)

non-sister chromatids link up forming chiasma and exchange genetic information through crossing over

second area of variation (meiosis)

late in meiosis I, tetrads migrate and line up randomly along center line of cell

third area of variation (meiosis)

in meiosis II, sister chromatids separate into gametes with a single copy of each gene occurring in each gametic cell; alignment prior to separation is random

nondisjunction

during cell divisions in meiosis I and II, one cell ends up with both pairs of homologs of one chromosome

trisomy

three copies of the chromosome after fertilization; Down Syndrome

monosomy

only one copy of a chromosome after fertilizationl Turner’s Syndrome

aneuploidy

too many or too few chromosomes; happens in 10% of meiotic divisions, and most result in fetal death

unequal crossing over

one arm of a chromatid ends up longer than its sister; Huntington’s Disease

transformation (asexual repro)

bacterial cells take up DNA fragments from other cells and either incorporate into the bacterium’s DNA or are left as a separate plasmid which replicates independently from the parent cell

transduction (asexual repro)

viral capsids attach to bacterial cells and inject their DNA, which fragments the host’s DNA

conjunction (asexual repro)

cytoplasmic tube made from cell with a plasmid to a cell without the plasmid and the plasmid is transferred

practical genetics

farmers knew you could select certain livestock/plants that provided some benefit and breed them so that the resulting offspring provide the same benefits

blending

offspring traits should be a blend of their parents

Mendel’s Law of Segregation

particles (alleles) separate, without dilution, into gametes where each gamete contains one particle (allele) of each trait (gene)

test cross

an individual is crossed with a homozygous recessive individual and the resulting offspring phenotype distribution tells you what the unknown parent is

reciprocal cross

crossing the opposite way (e.g., switching the traits of male and female parents)

XX

female

XY

male

autosomal inheritance

inheritance of genes located on non-sex chromosomes

sex-linked inheritance

inheritance of genes located on the sex chromosomes

What determines sex: the X or Y chromosome?

presence of a Y chromosome determines sex

sex-linked traits

male-pattern baldness, color-blindness, hemophilia

multiple allelism

occurrence of more than two alleles for a locus in a population, even though only one occurs on each chromosome

human blood types

3 alleles at one locus

beta-globin gene

in humans for making hemoglobin has over 500 alleles that affect many variations including altitude, temperature, and resisting disease

Mendel’s First Law - The Law of Segregation

states that in diploid organisms two alternate, homologous alleles segregate from each other in the germplasm and are passed separately without dilution in gametes to the next generation

Mendel’s Second Law - The Law of Independent Assortment

states that alleles of one gene are passed to the next generation independently of alleles of another gene, and that the process obeys the rules of random probability

probability

a measure of the frequency of occurrence, or likeliness, of a given, or desired, event; can be described as a number between 0 (impossibility) and 1 (certainty)

ratio

number of favorable outcomes compared to the number of unfavorable outcomes

mutually exclusive

events that cannot happen at the same time

independent

events that are not affected by previous events, nor do the events affect each other

gambler’s fallacy/fallacy of maturity of chances

mistaken belief that if something happens more frequently than what is considered normal, then it will happen less frequently than normal in the future, even if the observer knows that the independent probability of that event occurring is already established

variation

differences that exist between individual organisms in their structures, functions, and behaviors

wokring hypothesis

guiding research question or idea

null hypothesis

a defined statement meant to be disproved in order to eliminate possibilities, and eventually reach a correct conclusion

alternative hypothesis

needed in the event that the null is rejected and is typically the opposite of the null hypothesis; usually reflects the working hypothesis, but doesn’t have to

degrees of freedom

measure of size in a chi-square test

Carolus Linnaeus

began creating a set of rules for the naming of plants and attempted to classify all the plants he could get his hands on; did not invent binomial nomenclature, but used it so much that people give him credit for establishing its use

binomial nomenclature

two descriptive words given to identify a species; genus and species are the groupings used to name an individual type of organism

taxonomic hierarchy

a system of classifying and naming species for the purpose of understanding and establishing relatedness between species or larger groupings