Please enable JavaScript.
Coggle requires JavaScript to display documents.
The Function and Process' of Evolution (Qualities of a Species…
The Function and Process' of Evolution
Darwin & Descent with Modification:A History of Evolution
Charles Darwin
A naturalist, 1809-1882, English
A fateful voyage on the vessel the Beagle, taking him across South America, most importantly to the Galapagos Islands
Noticed the variation in species of finches, their beaks, on the Galapagos Island
Adaptations
Inherited characteristics of organisms that enhance their survival and reproduction in specific environments
Darwin used the term 'Descent with Modification' to describe his view instead of evolution
Wrote the book "On the Origin of Species by Means of Natural Selection"
Definitions
Macroevolution
Evolution of a species on a large scale
Microevolution
Evolution of a species on a smaller, less obvious scale
Artificial Selection
Humans have modified other species over many generations by selecting and breeding individuals that possessed desired traits
Paleontology
The study of fossils
Natural Selection
A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than others because of said traits
Geological Strata
New layers of sediment that cover older ones and compress them into super imposed layers of rock
Endemic
A species found nowhere else in the world
Cladogram
A branching diagram showing the relationships and ancestry between species
Pangea
All of earth's landmasses combined into one single continent
Biogeography
The scientific study of the geographic distributions of species
Homology
Related species can have characteristics with underlying similarity yet that serve different functions
Homologous Structures
Structures that represent variations on a structural theme that was present in a common ancestor
Vestigial Structures
Remnants of features that serves a function in the organism's ancestors
Evolutionary Tree
A diagram that reflects evolutionary relationships among groups organisms
Convergent Evolution
The independent evolution of similar features in different lineages
Analogous Structures
Features that share a similar function but not a common ancestry
Qualities of a Species
Biological Species Concept
"A species is a group of populations whose members have the potential to interbreed..[producing] viable, fertile offspring"
Reproductive Isolation
Biological factors that prevent two individuals from producing offspring
Hybrids
Offspring resulting from interspecific mating
Zygotic Barriers
Pre
"Before the zygote"; Block fertilization from occurring
Gametic Isolation
Sperm of one species may not be able to fertilize the egg of another
Mechanical Isolation
Morphological differences prevent positive reproduction
Behavioral Isolation
Courtship rituals and other specific behaviors only unique to the individual species
Temporal Isolation
Breed at different times (day, seasons, years, etc.)
Habitat Isolation
Two species occupy different habitats, encountering each other rarely
Post
"After the zygote"; May contribute to reproductive isolation after hybrid is formed
Reduced Hybrid Fertility
Hybrids may end up being sterile, thus not able to reproduce and survive
Hybrid Breakdown
First generation may be fertile, but as they reproduce, their line ends because their offspring end up being sterile or weak
Reduced Hybrid Viability
Genes of the parents may leave the hybrid weak or underdeveloped and unable to survive
Geographic Seperation/Isolation
Allopatric Speciation
"Other Country" speciation
Gene flow is interrupted when a population is geographically isolated into subpopulations
Depends on an organisms ability to cross barriers and close the isolation
Sympatric Speciation
"Same Country"; Occurs in populations that live in the same geographic area
Sexual Selection
Selection or preference of a mate, due to a variation or difference in the population, providing a barrier of preference
Habitat Differentiation
A subpopulation uses a habitat or resource that the parent population does not, driving a wedge in that species
Polyploidy
A species originated on accident during cell division that results in extra sets of chromosomes
Autopolyploid
An individual that has more than two chromosome sets that are all derived from a single species
Hybrid Zones
A region in which members of different species meet and mate, producing some offspring of mixed ancestors
Fusion
Weakening reproductive barriers, causing the gene pools of two species to become increasingly alike
Stability
Continued formation of hybrid individuals
Reinforcement
Process of reinforcing reproductive barriers
Typically located where the habitats of interbreeding species meet
Rate of Speciation
Punctuated equilibria
Periods of apparent stasis punctuated by sudden change
Other species in comparison have slow changes over long periods of time
Population Evolution
Genetic Variation
Differences among individuals in the composition of their genes or other DNA sequences
Altering Gene Number or Position
Large scale genetic changes that leave genes intact do not effect the organisms phenotype, passing those genes along
Rapid Reproduction
Mutations can quickly produce genetic variation in species that can reproduce quickly
Formation of New Alleles
New alleles can arise by mutation
Point mutations can result in neutral variation, DNA sequences differences that don't give a selective advantage or disadvatage
Sexual Reproduction
Variation from unique combinations of alleles that come from parents
Hardy-Weinberg equation
Named for the British mathematician and German physician who developed the idea in 1908
In a population that is not evolving with allele and genotype frequencies remaining constant between generations
p + q = 1
p^2 + 2pq + q^2 = 1
Often used as an initial test to see if evolution is occurring in a population
Genetic Drift
Chance events causing allele frequencies to fluctuate unpredictably from one generation to the next, especially in smaller populations
Founder Effect
When some individuals become isolated away from the larger population and begin to reproduce, producing a new population with varied genes
Bottleneck Effect
A sudden change in environment, severely changing the size of a population
Certain alleles may be more present in the surviving population
Gene Flow
The transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes
Alleles transferred by gene flow can affect how well populations are adapted to local environmet conditions
Natural Selection
Relative Fitness
The contribution an individual makes to the gene pool of the next generation relative to others contributions
Directional Selection
When conditions favor individuals exhibiting one extreme of the phenotypic range
Disruptive Selection
When conditions favor individuals at both extremes of the phenotypic range
Sexual Selection
A process in which individuals with certain characteristics are more likely to get mates than other of the same sex
Intersexual Selection
Selection within the same sex, individuals of one sex compete directly for mates of the opposite sex
Intrasexual Selection
Mate choice, individuals of one sex are choosy in their mates of the opposite (usually females)
Sexual Dimorphism
A difference in secondary sexual characteristics between males and females of the same species
Balancing Selection
Selection itself may preserve variation at some loci, maintaining two or more phenotypic forms in a population
Frequency-dependent selection
The fitness of a phenotype depends on how common it is in a population
Heterozygote advantage
Individuals who are heterozygous at a particular locus have greater fitness than do both kinds of homozygotes
Defined in terms of genotype
Stabilizing Selection
Does not lean towards either extreme, and favors those with intermediate characteristics