AP Bio Unit 1 Test Prep

4 Parts Necessary for Natural Selection

Variation in traits, heritable traits, competition and overproduction

Homologous Structures

structures in different species that are similar because of common ancestry

Analogous Structures

structures in different species that are similar independent of ancestral relation

Convergent Evolution

evolution of the similar features in independent evolutionary lineages

Divergent Evolution

the evolutionary process through which speciation occurs

DNA

contains genetic information and genes

Alleles

a form of gene, often represented by a capital or lowercase letter, which codes for a trait

Recessive Allele

an allele represented by lowercase letters and does not appear unless both alleles of a gene are recessive

Dominant Allele

represented by a capital letter and can show up only if one is present

Genotype

the genetic makeup of an organism

Homozygous

a type of genotype where both alleles are the same

Heterozygous

a type of genotype where the alleles are different

Monohybrid Cross

a genetic experiment to observe inheritance of one trait (one homozygous dominant and one homozygous recessive)

Phenotypes

physical traits of an organism

Genes

region of DNA containing information to make proteins

Mircoevolution

evolution on a smaller scale that measures the change in allele frequencies in a population over generations

Gene Pool

set of all genes/genetic information in a population

Hardy Weinberg Equation

p² + 2pq + q² = 1. p + q = 1

What does p and q represent in Hardy-Weinberg Equation?

p = dominant allele frequency, q = recessive allele frequency

What are the assumptions of the Hardy-Weinberg Equilbrium?

Large population, random mating, no mutation, no migration and equal fitness among genotypes

Genetic Drift

chance events that cause random changes to frequencies of alleles, especially dominant in smaller populations

Founder Effect

A form of genetic drift where a small, isolated population does not reflect the gene pool of the larger population

Bottleneck Effect

a form of genetic drift that occurs when only a small number of individuals survive from the original population whose gene pool is not reflective of the original

Gene Flow

transfer of alleles from one population to another which results from the movement of fertile individuals

Fitness

the likelihood that an individual of a population is to survive and reproduce

Relative Fitness

the measure of an individual’s reproductive success compared to others in the population

Directional Selection

conditions that favor individuals exhibiting one extreme of a phenotype, resulting the frequency curve in that direction

Disruptive Selection

conditions that favor individuals at both extremes with the intermediate phenotypes selected against

Stabilizing Selection

conditions where the intermediate variant is preferred over the two extremes for a phenotype

Heterozygote Advantage

In some species, it is more evolutionary advantageous to be heterogenous for a deleterious trait for some benefit; also preserves variation in the gene pool

Sexual Selection

a process by which one sex of a species decides who to mate with due to a specific trait in a limited # of potential mates

Sexual Dimorphism

Acquired differences between sexes of the same species to boost reproductive success

Macroevolution

processes that give rise to newer species & higher taxonomic groups

Taxon

A group of species, families or classes that are similar to one another which form to make one unit

Heritability

a measure of how well differences in people’s phenotypes account for their genotypes

Inbreeding

Mating of closely related individuals in a species

Nonrandom Mating

Mating choice is not random, i.e. brighter tail fur = more mates

Polymorphism

The occurrence of two or more different phenotypes in the population of a species

Genetic Variability

The diversity of alleles & genotypes in a population

Assortative Mating

Individual preference to mate with those phenotypically similar

Cline

The variation of individuals in a population due to geographical differences, i.e. larger bodies of warm-blooded animals near poles to conserve heat

The Handicap Principle

Individuals with better fitness signal their superiority through morphology that lowers their fitness, i.e. brighter feathers = more investment into feathers

Good Genes Hypothesis

Certain phenotypes are signals of genetic superiority which can enhance reproduction

Phylogeny

the study of the evolutionary history of a species or a group of species based on DNA sequence analysis

Does King Phillip Come Over For Good Soup?

Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species

Binomial Nomenclature

first part is genus followed by name unique for each species

Shared Ancestral Characteristic

characteristic that originates in an ancestor of the taxon

Shared Derived Characteristic

a characteristic unique to a clade which is not seen in other clades or common ancestors

Molecular Clock

an approach to measure time of evolutionary change based on the given fact that some genes evolve at a constant rate

Horizontal Gene Transfer

the transfer of genes between different organisms rather than through reproduction

Endosymbiont Theory

a theory which proposes that eukaryotes descended from multiple prokaryotes

Nucleus-First Hypothesis

a theory which proposes that the nuclei of eukaryotes was formed prior to endosymbiosis of prokaryotes

Mitochondria-First Hypothesis

a theory which proposes that mitochondria were the first endosymbionts before the proper development of nuclei and other membrane-bound organelles

Eukaryote-First Hypothesis

a theory which proposes that eukaryotes came first, and prokaryotes evolved from losing complexity

Speciation

the splitting of one species into two or more distinct species

Species

a group of populations whose members have the potential to interbreed in nature and produce, viable fertile offspring

Reproductive Isolation

the existence of biological factors that prevent members of two species from interbreeding and restricting gene flow

Prezygotic Barriers

barriers such as temporal, morphological, behavioral, geographical isolation which prevent the fertilization of species

Postzygotic Barriers

barriers such as infertile hybrids which prevent the further growth of the hybrid population

Allopatric Speciation

Speciation that results when there is a geographical barrier preventing gene flow between two populations

Sympatric Speciation

Speciation that results whilst there are no geographical barriers between two populations which can prevent gene flow

Polyploidy

the result of accidental cell division when an organism has more than two complete chromosome sets

Punctuated Pattern

the process of speciation where there is relatively no change until something changes and speciation occurs quickly

Gradual Pattern

the process of speciation slowly in thousands or millions of years

Fossil Record

the history of life as documented by fossils found all over the world

Trace Fossils

fossils such as footprints of extinct species

Molds/Cast Fossils

fossils such as impressions of an organism or a mold filled with sediment

Replacement Fossils

Fossils replaced with mineral crystals that leave detailed replicas such as ambers

Radiometric Dating

the process of determining the absolute age of rocks and fossils based on the half-life of certain radioactive isotopes and their concentrations

Mass Extinction

a period in time which results the extinction of large numbers of species resulting from sudden global environmental changes

How many mass extinctions are there?

5, and scientists argue that humans are causing the sixth.

Permian Mass Extinction

Occurring 250 million years ago, this was the biggest of the mass extinctions. This was caused by a volcanic eruption which resulted in a dramatic increase in CO2, causing global warming and ocean acidification.

Cretaceous Mass Extinction

Occurring 66 million years ago, this occurred due to a meteorite striking the Earth, setting debris and blocking sunlight for many months and eliminating many plants and animals.

Adaptative Radiation

Periods of evolutionary change in which groups of organisms from the few surviving species fill out emptied out ecological niches after a mass extinction

What was the purpose of the Miller-Urey Experiment?

The purpose of the Miller-Urey experiment was to emulate the conditions of pre-historic Earth and get answers on the origin of species.

What was the conclusion of the Miller-Urey Experiment?

The scientists concluded that it was indeed possible for amino acids such as glycine to form simply from the chemical reactions occurring in this ancient Earth.

Cyanogenesis

the ability to create cyanide by a species

Cyanide

a dangerous group of chemicals that result in the degradation of ATP for infected individuals and quick death if in high concentration