Campbell Biology: Cambell Flashcards

ability of a trait to be passed on to offspring

Decent with modification

inherited characteristics of organisms that enhance their fitness in specific envrionments

quantifiable measure of survival and reproductive success

process in which individuals that have certain inherited traits tend to have a higher fitness because of those adaptations

Variation: 1. must be present in the population
2. must affect fitness
3. must be inherited

the process in which humans modify organisms by selecting and breeding organisms with certain traits

structures in different species that have a general theme because of common ancestry, but structures may vary in form and function

remnants of structures that serve an important function in the ancestor, but not in the present organism

the geographic distribution of species

the independent evolution of similar features in different lineages due to similar environmental pressures

The change in allele frequencies in a population over time

all the individuals of one species in a particular area

a discrete unit of hereditary info. consisting of a specific nucleotide sequence in DNA

the genetic makeup, or set of alleles, of an organism

any alternative versions of a gene that may produce distinguishable phenotypic effects

observable traits of an organism that are determined by genotype

homozygous dominant or heterozygous genotype

homozygous recessive genotype

differences among individuals in the composition of their genes or other DNA segments

variations in appearance due to environmental influences

1. nucleotide variability- at the molecular level of DNA
2. gene variability- at the whole gene level, which is quantified by average heterozygosity

differences in the genetic composition of separate populations

a graded change in character along a geographic axis

1. Formation of new alleles through mutation
2. Altering gene number or position through chromosomal changes that delete, disrupt, or rearrange loci
3. Rapid reproduction can increase mutation rates
4. Sexual reproduction due to: crossing over, independent assortment of alleles, fertilization

1. no mutations
2. no gene flow
3. random mating occurs
4. population size is large
5. no selection occurs

p+q=1

p(squared)+ 2pq + q(squared)=1

chance events that can cause unpredictable fluctuations in allele frequencies from one generation to the next

When a few individuals become isolated from a larger population

a reduction of population size due to a sudden change in environment

movement of alleles into or out of a population

immigration- move into
emigration- move out of

process in which individuals that have certain inherited traits tend to have higher fitness because of those adaptations

contribution an individual makes to the gene pool of the next generation relative to the contributions of other individuals

one end of distribution is favored

both ends of the distribution are favored

intermediates of the distribution are favored

a form of selection in which individuals with certain phenotypes are most likely than others to obtain mates

individuals of the same sex compete for access to mates

individuals of one sex choose their mates of the opposite sex

occurs when natural selection maintains variation in the population
2 ways: Heterozygote advantage
Frequency dependent selection

heterozygotes have a greater fitness than both homozygotes

the fitness of the phenotype depends on how common it is in the population

1. selection can act only on existing variations
2. evolution is limited by historical constraints
3. adaptations are often compromises
4. chance, natural selection, and the environment interact

the process by which one species splits into 2 or more species

defines species as a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but do not produce viable, fertile offspring with member of other such groups.

the existence of biological factors(barriers) that impede members of 2 species from interbreeding and producing viable, fertile offspring

block fertilization from occuring

reproductive isolation occurs after the hybrid zygote is formed

species occupy different habitats with in the same area and therefore rarley encounter each other

species that breed during different times of the day, season, or years

courtship rituals that attracts mates and enables mate recognition

Mating is attempted, but morphological differences prevent a successful completion

mating is attempted, but the sperm of one species is unable to fertilize the egg of another species

Zygote forms but either the embryo does not develop or the offspring doesn't survive in its environment

the hybrid is healthy, but is infertile and cannot produce offspring

when a viable, fertile hybrid reproduces, but their offspring are feeble or sterile

characterizes species by body shape and structure features

defines species based on ecological niche

defines species as the smallest group of individuals that share a common ancestor

occurs because gene flow is interrupted when a population becomes geographically isolated

speciation occurs without geographic separation

an accident in cell division that results in extra set of chromosomes

genetic factors enable a subpopulation to exploit a habitat or resource not used by the present population

a subset of the population starts choosing the opposite sex based on specific characteristics

a region in which members of different species meet and mate, producing some offspring of mixed ancestry

process of natural selection strengthening the pre-zygotic barriers reducing the chances of hybrid formation

weak reproductive barriers increase gene flow between the 2 species causing the 2 hybrid species to fuse into single species

Hybrids continue to be produced because the hybrids survive and/or reproduce better than the parent species

periods of stasis followed by sudden change

change occurs gradually over long periods of time

broad pattern of evolution above the species level
-revealed through fossil record

1. the abiotic synthesis of small organic molecules, such as AA and nitrogenous bases
2. the joining of these small molecules into macromolecules
3. the packaging of these molecules into protocell droplets with membranes that maintained internal chemistry different from the surroundings
4. The origin of the self-replicating molecules that eventually made inheritance possible

a technique of dating rocks and fossils based on the fixed rate of radioactive isotope decay

Amount of time required for 50% of the parent isotope to decay

-infolding of plasma membrane--created ER, nuclear membrane
-endosymbiotic theory-cell engulfing a prokaryote---created mitochondria, chloroplasts, plastids

Led to the great innovation of specialization
- Colonial unicellular organisms let to multicellular organisms

burst of evolutionary change that occured in a short geological period , which includes the appearance of many present day animal phyla

process in which the earth's mantle causes the continental plates to move
-promotes allopatric speciation on a grand scale

periods of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles in their communities

1. larger size
2.more complex molar teeth
3. fewer toes

most extensive loss. 96% of plants and animal species perished

most famous and well studies. Caused by meteorite causing mass forest fire and smoke blocked sun, dinosaurs died off while placental mammals flourished

disciplin in which organisms are named and classified

taxonomic unit at any level

the scientific name of an organism that consists of a genus and species

a discipline focused on classifying organisms and determining their evolutionary relationships

the evolutionary history of a species or group of species

branching diagram that represent the evolutionary history of a group of organisms

represent common ancestor

where lineages diverge

a branch point where more than 2 taxa emerge

groups that share an immediate common ancestor

lineage that diverges early in the history of the group

genotypic and phenotypic similarities due to sharing ancestry

Phenotypic similarities, but no shared ancestry

process of similar adaptations evolving in organisms from different evolutionary lineages due to similar environmental pressures

a taxa that is closely related to the group of organisms that you are studying, but are not part of your study group

shared derived characters that represent departure from the ancestor

shared ancestral characters that evolved prior to the most recent common ancestor

a group that consists of the ancestral species and all of its descendants

a group that consists of the ancestral species and some, but not all of its descendants

a group that doesn't include the closest common ancestor

Archaea
Bacteria
Eukarya

Plantae
Fungi
Animalia
Protista