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127 Cards in this Set

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Related species have similar characteristics, but different functions. Also it shows the same branching pattern in evolutionary history.
Geographic distribution of species.
Darwin saw closely related species tend to be found in the same geographical regions
Remnant structures that were important to the ancestors
Vestigial Organs
Gave evidence that many species of organisms inhabit earth
Origin of Species
Population changes over generations when individuals with heritable traits leave more offspring than others. Only apparent in the population of organisms over time not in the individual
Natural Selection
Accumulations of inherited characteristics that enhance the organisms chance to survive and reproduce in specific environment.
Evolutionary Adaptation
Malthus’s idea that the capacity to reproduce is a characteristic in all species.
“Struggle for existence”
All organisms related through descent from a common ancestor of the past. They inhabited different habitats over years and adapted through modifications.
Descent with Modification
A change over time in the genetic comparison of a population. Enough changes can give rise to a new species. Changes are measured in relative proportions if heritable
Each boundary between the strata had a major event, which destroyed organisms
Idea that profound change took place continually, slowly, and was a cumulative effect
Parts of the body become larger and stronger because of extensive use and vice versa
Use and Disuse Principle
Organism could pass the modifications to the offspring
Inheritance of Acquired Characteristics Principle
A heritable feature that varies among individuals.
Example: A Flower’s Color
Variant of a character
Example: White or purple flower
All the offspring are of the same variety. Called the P generation.
True-Breeding Method
Mating of two true-breeding varietiesàF1 Generation
Alternative versions of the genes account for variations in inherited characters. For each character and organism inherits two alleles, one from each parent. One dominant one recessive.
Law of Segregation
Diagram that predicts the allele composition of offspring from a cross between individuals
Punnett Square
Each pair of alleles segregates independently of other pairs of alleles during gamete formation
Law of Independent Assortment
An organism having a pair of identical alleles for a character
An organism that has two different alleles for a gene; not true-breeding. Called carriers for diseases.
Organism’s traits [PP and Pp = purple flowers… white flowers]. Also all aspects of physiological traits like being able to pollinate.
à Percentages
Organism’s genetic makeup [difference between PP and Pp… homozygous and heterozygous]
Being heterozygous for one character. Cross between heterozygotes.
Heterozygote for both character à YYRR + yyrr = YyRr
Breeding method of a recessive homozygote with an organism of dominant Phenotype but unknown genotype
Phenotype of heterozygote and homozygote are undistinguishable
Complete Dominance
Both alleles affect the phenotype in separate, distinguishable ways
Alleles for some characters fall in the Middle of the spectrum of dominance.
Example: Pink snapdragons
Incomplete Dominance
Multiple phenotypic effects that can lead to hereditary disease like sickle cell and cystic fibrosis
A gene at one locus alters the phenotypic expression of a gene at a second locus.
Example: Coat color of mice
Characters that vary in the population
Quantative Characters
An additive effect of two or more genes on a single phenotypic character.
Example: Skin is determined by at least 3 genes.
Polygenic Characters
Genotype is associated with a range of phenotypic possibilities due to environmental influences.
Example: RBC varies with health
Norm of Reaction
Many factors both of genetic and environment influences phenotype
Evolutionary change on a small scale concerning genetic makeup or a population from one generation to the other
Study of how populations change genetically over time
Population Genetics
Comprehensive theory of evolution that integrates ideas from many other fields
Modern Synthesis
A localized group of individuals capable of interbreeding and producing offspring. Can be isolated from each other and unable to exchange genetic material.
The accumulation of genes in a population at a certain time. Consists of all the alleles at all gene loci in all individuals in the population.
Gene pools
The frequencies of alleles and genotypes in a population’s gene pool remains constant from generation to generation when Mendelian segregation
Hardy-Weinberg Theorem
Extremely large population size. No gene flow. No mutations. Random mating. No natural selection.
Hardy-Weinberg Conditions
Changes in nucleotide sequence of DNA and produces variation in gene pools
Can be as little as one base change in a gene, but can significantly impact the phenotype; most are harmless
Point Mutation
An important source of variation and can give rise to new genes
Gene Duplication
More important than mutations on a generation basis, creates possibilities for adaptations, rearranges alleles in fresh combos, does not change frequencies!
Sexual Recombination
One of the three main factors that alter allele frequencies and cause the most evolutionary change, over time it reduces genetic variation through loss of alleles in the gene pool
Genetic Drift
Large impact on the population due to a sudden change and have few survivors; can be cause by humans on other species
Bottleneck Effect
When individuals become isolated from the larger population and create a new population that does not reflect the larger gene pool. Also called “Isolation Bottleneck”
Founder Effect
Genetic additions or subtractions from a population due to movement of gametes or fertile individuals; generally reduces differences in populations
Gene Flow
A population displaying a character that has two or more different forms/morphs that have high noticeable frequency.
Example: Wing and Wingless Insects
Phenotypic Polymorphism
Heritable component for alleles at several loci; example: height
Genetic Polymorphism
Differences in gene pools of separate populations or subgroups
Geographic Variation
Graded change in a trait along a geographic axis
The contribution an individual makes to the gene pool of the next generation
Most reproductive is set the number 1
Relative Fitness
Occurs when a population’s environment changes or migration to a new habitat happens and shifts frequency curve for phenotypic character to favor the average
Directional Selection
Occurs when conditions favor the endpoints/extremities of the phenotypic range
Disruptive Selection
Favors intermediate variants causing a large skinny peak, reduces variations, maintains a particular phenotypic character
Stabilizing Selection
Genetic variation are hidden in recessive alleles. Natural selection protects the rarer recessive alleles
When natural selection maintains stable frequencies of two or more phenotypic forms in a population=> balanced polymorphism
Balancing Selection
Have greater fitness than homozygotes in certain situations like environment favors them.
Heterozygous Advantage
Fitness of any morph decreases if it is too common in the population and preserves polymorphism
Frequency-Dependent Selection
Natural selection for success
Sexual Selection
Seen in secondary sexual characteristics and not associated with reproduction
Sexual Dimorphism
Competition within the same sex for the opposite sex
Intrasexual Selection
Mate choice
Intersexual Selection
Genetic variation is achieved through meiotic recombination and fertilization and enables further adaptations
Sexual Reproduction
Appearance of new species is the source of biological diversity
Refers to evolutionary change above species level.
Example: development of feathers in a bird
Also called phyletic evolution. Accumulation of changes that gradually transforms a species with different characteristics
Called branching evolution. Splitting of the gene pool into two or more separate pools, Gives rise to a new species, The only one that can promote biological diversity
A species is a population or group of populations whose members have the potential to interbreed in nature and produce viable and fertile member ONLY in its population.
Biological Species Concept
Existence of biological factors/barriers that impede members of the population to produce viable and fertile offspring and can isolate the gene pool
Reproductive Isolation
Hinders the fertilization of ova if the members of a different species attempt to mate
Prezygotic Barriers
Two species that occupy different habitats in the same area.
Example: One garter snakes live in water and the other on land
Habitat Isolation
Species that breed different times of day, seasons, and years. Cannot mix gametes
Temporal Isolation
Unique courtship behaviors to a species as an effective reproductive barrier
Behavioral Isolation
Morphological differences.
Example: Attracting different pollinators.
Mechanical Isolation
Sperm of one species cannot fertilize eggs of another
Gametic Isolation
Prevents the hybrid zygote from developing into a fertile and viable adult
Postzygotic Barrier
The genes of a different parent species can interact and impair the hybrid’s development. Can become frail because of lack of development
Reduced Hybrid Viability
Can become sterile due to failed meiosis to produce normal gametes.
Example a sterile mule is from donkey and horse.
Reduced Vertile Fertility
The next generation is feeble and sterile when the F1 generation mate with parents’ species or their own
Hybrid Breakdown
Gene flow is interrupted when a population is divided into geographically isolated subpopulations. New species form and is isolated from parent population
Allopatric Speciation
Speciation takes place in geographically overlapping populations or there is a reproductive barrier from the parent population or environmental changes
Sympatric Speciation
Mutational change resulting in extra sets of chromosomes
An individual that has more than two chromosome sets
Example: 2n=>4n; If mated with diploid = tetraploid (3n) and is sterile due to unpaired chromosomes
Evolution of many diversely adapted species from a common ancestor upon introduction to various environmental opportunities and challenges. Organisms journey to distant areas due
Adaptive Radiation
Claimed 96% of marine animal species and terrestrial life. Occurred during time of volcanic eruptions, produced carbon dioxide to warm the earth and marked by oxygen
Permian Mass Extinction
Terminated the life of half the marine species, families of terrestrial plants and animals, and dinosaurs.
Cretaceous Mass Extinction
Collections of autonomously replicating cells that became specialized for different functions
Most of the major phyla of animals appeared 20 million years of the Cambrian Period
Cambrian Explosion
Earth’s continents are not fixed, plates push or pull to each other. Mesozoic era/180 million years ago when continents drifted apart
Continental Drift
When a new species of fossil record appears in a geologic stratum for several strata then disappears
Punctuated Equilibrium
Sterile hybridàfertile polyploid and Cannot breed with parents’ species
Complex structures evolved in increments from simpler versions that performed the same basic function
Example: The eye
Evolutionary Novelties
Affects the evolution of morphology by altering the rates at which various body parts develop or by changing the timing of completion of a part’s development.
The proportioning that helps gives a body it’s specific form during development
Allometric Growth
Sexually mature stage of a species retaining body features that were juvenile structures. Alteration causes some animals to appear different than ancestors
Determines basic features where the location of a particular part will develop
Example: Hox gene controls the position of an embryo
Homeotic Genes
Species undergo natural selection where the most newest offspring determines the direction of major evolutionary trends
Species Selection
The evolutionary history of a species or group of species. Draw fossil records to construct phylogeniesàinfo about ancient organisms
An analytical approach to understanding the diversity and relationships of organisms. Studies morphological and biochemical resemblances among organisms to infer
Uses DNA, RNA, and other molecules for comparisons
Molecular Systematics
Reflects hierarchical classification of groups
display hypothesis and evolutionary relationships. Constructed from dichotomies or two way branching points
Phylogenetic Tree
Based on the sequence in which fossils have accumulated in stratum and help to establish relationships between living organisms
Fossil Record
Relates to convergent evolution when making a phylogeny
Analogous structures that evolved independently
An ordered division of organisms into categories based on a set of characteristics used to access similarities and differences
Two part format of scientific name
The first part of the binomial to which the species belong and always capitalized
Second part that refers to one species within genus and always in lowercase
Specific Epithet
Common names for organisms in Latin
Binomial Nomenclature
Hierarchical Classification
Diagram displaying patterns of shared characteristics and common ancestry as the base of the tree
A group of species that includes an ancestral species and ALL its descendants
Analysis of how species are grouped into clades
Lacking some members of the clade. Has common ancestor but not all descendants.
Group of species with no common ancestor
A character that is shared beyond the taxon we are tying to define
Shared Primitive Character
An evolutionary novelty unique to a particular clade
Shared Derived Character
A species or group of species that is closely related to ingroup and Used to differentiate between shared derive characters and shared primitive characters
Presents info about the sequencing of events relative to one another. Branches reflect the number of changes taken place in a specific DNA sequence in a specific lineage
Present info about actual time that given events occurred. Branches are of equal length to common ancestor.
Ultametric Tree
Given certain rules of DNA changes over time, a tree that reflects the most likely sequence of events. Are complex and incorporate as much information as it can.
Maximum Likelihood