Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
100 Cards in this Set
- Front
- Back
James Hutton
|
Formulated the concept of Uniformitarianism: that there is a consistent, slow, gradual geologic change through time. This concept is supported by evidence of plate tectonics and erosion.
|
|
Charles Lyell
|
Popularized the theory of Uniformitarianism in his Principles of Geology in 1830. Darwin was given a copy of his book by FitzRoy during his voyage on the Beagle, which largely influences his discoveries.
|
|
Thomas Malthus
|
Was influential in the field of political economy and demography. He developed the Principle of Population which states that with population growth, resources become limited, which applies to Darwin's evolutionary perspective that those with greater fitness will have greater chance of survival and produce more offspring.
|
|
Adam Smith
|
Expert on economics, competition, and capitalism. Stated that the fittest in the market will survive in the economic population, and variation is good because it increases the abilities for some to succeed.
|
|
Carl Linne (Carolus Linnaeus)
|
Father of Modern Taxonomy. Popularized binomial nomenclature of classifying organisms and developed Hierarchal Taxonomy. Published Systema Naturae and used systematics to categorize diversity among species.
|
|
Jean Baptiste Lamarck
|
Zoologist, botanist, and curator at the Paris Natural History Museum. He developed first comprehensive theory of organic evolution, including a mechanism of acquired characteristics. He viewed evolution as a force driving animals from simple to complex forms.
|
|
Flaw of Lamarck's view of Evolution
|
He believed in "acquired characteristics" and that they could be passed down to offspring. A blacksmith is not big because he was blacksmith, rather he is a blacksmith because he is genetically prone to larger stance and more muscular strength than average men.
|
|
Lamarckian Evolution
|
Organisms change in a linear fashion producing a ladder of life: bacteria (spontaneous generation) → fungi → green algae → land plants → invertebrates → vertebrates → humans
|
|
Eidos
|
Refers to the ideal state of organisms conceptualized by Plato. Variations are mistakes in trying to achieve perfection. Similar to: social norms; schemas.
|
|
Scala Naturae
|
As hypothesized by Aristotle, a Great Chain of Being exists to fix species characteristics throughout time. Hindered the advancement of evolution.
|
|
Uniformitarianism
|
Geologic change occurs slowly, gradually, and consistently through time. Idea formulated by James Hutton, supported by plate tectonics and erosion.
|
|
How Biogeography Influenced Darwin
|
Darwin documented patterns of biogeography that suggested common descent of species. Ex: Rheas in Patagonia (similar to ostrich or emu); mockingbirds, finches, and tortoises in Galapagos (different species bearing similar characteristics due to geographic isolation)
|
|
Biogeography
|
The study of the distribution of biodiversity over space and time.
|
|
How Fossils Influenced Darwin
|
He discovered many fossils which were similar to current South African species. Also discovered many fossils of species that have gone extinct, fossil record has transitional forms, and vestigial traits exist: influenced his view that species are not immutable but change through time.
|
|
Theory of Evolution
|
Evolution of new species occurs by descent with modification from ancestral species. The driving mechanism by which this occurs is natural selection.
|
|
Fitness
|
The ability of an individual to produce offspring relative to others in the population.
|
|
Adaptation
|
A heritable trait that increases fitness.
|
|
Vestigial Traits
|
Leftover, non-functional traits. Ex: human coccyx, appendix, goosebumps.
|
|
Homologous Traits
|
Similarities between two species that are derived from the same common ancestor.
|
|
Vertical Evolution
|
Genetic modification through time. Creates homologous traits between species, often paralogous or orthalogous.
|
|
Orthologs
|
Genes acquired via common descent; speciation event. Genes that are found within one clade, descended from a common ancestor. Often, but not always, have the same function.
|
|
Paralogs
|
Gene duplication event. Typically have the same or similar function, but sometimes do not: due to lack of the original selective pressure upon one copy of the duplicated gene, this copy is free to mutate and acquire new functions.
|
|
Horizontal Gene Transfer
|
Any process in which an organism incorporates genetic material from another organism without being the offspring of that organism. Most common in bacteria, likely to have been a prevalent mechanism during evolution of eukaryotic cells
|
|
Gene
|
A polymorphic unit of heredity in a living organism. They have multiple alleles
|
|
Allele
|
Different versions of gene that might be found in a locus. If it is adaptive, it will survive and reproduce through the species.
|
|
Locus
|
Address of a gene.
|
|
Hardy-Weinberg Equation
|
Measures if allele frequencies change through time: if you know what the frequencies are of the alleles of this generation, you can predict the alleles of the next generation as long as evolution doesn't interfere
|
|
Natural Selection
|
Certain phenotypes produce more offspring and alleles associated with those phenotypes will increase in frequency and non-favored alleles will decrease.
|
|
Directional Selection
|
Allele frequencies change in one direction; favors one extreme of a trait distribution; lowers genetic variation; often counterbalanced by opposite selective pressure favoring the other extreme
|
|
Stabilizing Selection
|
alleles associated with mean trait values favored; no change in average trait value over time; genetic diversity is reduced; ex: birth weight.
|
|
Disruptive Selection
|
alleles associated with either extreme are favored; tends to increase genetic diversity; also important as a mechanism of speciation. Ex: black bellied seed cracker: both larger and smaller beaks ideal for survival.
|
|
Sexual Selection
|
Individuals differ in their ability to attract mates. Acts more strongly on males than females because females are hindered by childbearing and rearing while males only hindered by number of mates. Two types: female choice and male-male competition.
|
|
Female Choice
|
females respond to male phenotype to choose the fittest male to reproduce with.
|
|
Male-Male Competition
|
Males compete to breed with a female. The male with the highest adaptation will win and reproduce more.
|
|
Balancing Selection
|
Maintains less fit alleles in a population. Results in balanced polymorphism.
|
|
Balanced Polymorphism
|
Two mechanisms: Heterozygote Advantage (herterozygotes have higher fitness, as is sickle cell anemia creating an immunity to malaria) and Negative Frequency Selection (the more common allele is, less fit it becomes, and rare individuals have higher fitness).
|
|
Genetic Drift and Two Causes
|
Undirected Natural Selection caused by environment, due to random chance. Causes allele frequencies to drift up and down over time. Two Causes: Founder Effect and Genetic Bottleneck.
|
|
Sampling Error
|
Mechanism of Genetic Drift; Blind Luck.
|
|
3 Key Points to Genetic Drift
|
(1) Random with respect to fitness, (2) most pronounced in small populations, and (3) in time can lead to loss or fixation of alleles.
|
|
Founder Effect
|
Small number of emigrants form a new population. ex: Ellis-Van Creveld Syndrome in the Amish.
|
|
Genetic Bottleneck
|
Large population is suddenly reduced.
|
|
Gene Flow
|
Movement of allele between populations that happens when one individual leaves a population and mates with one of another population. Equalizes frequencies between populations, may increase or decrease fitness. Mechanism is migration. Acts against Speciation.
|
|
Mutation
|
Production of new alleles, typically mistakes in DNA during replication or repair. Increases genetic variation of a population. Amplified by large number of loci in the genome and natural selection if it increases fitness. However, most mutations lower fitness and are random with respect to fitness.
|
|
Inbreeding
|
Nonrandom mating between relatives of a population. Increases homozygosity and decreases heterozygosity. Does not change allele frequencies, does change genotype frequencies. Inbreeding depression = loss of fitness due to homozygosity increase. Increases elimination rate (via natural selection) of deleterious recessive alleles.
|
|
Neutral Evolution
|
Theory introduced by Kimura: Much of genetic variability is due to the accumulation of neutral mutations via genetic drift. This process is not subject to natural selection because is alters genotype without displaying a change in phenotype.
|
|
Concept of Species
|
Species are evolutionarily independent populations or group of populations. They have a common set of characteristics that set them apart from other species. They are formed via lack of gene flow and subsequent events of genetic divergence due to drift, natural selection, and mutation. Four different methods of classifying.
|
|
Biological Concept of a Species
|
Critical feature: reproductive Isolation. Members of a species can and do interbreed to produce viable offspring. Advantages: Strong theoretical foundation. Disadvantages: doesn't apply to fossils, asexual organisms, or geographically separated populations.
|
|
Evolutionary Species Concept
|
Species are determined via analysis of ancestry. Species = smallest identifiable lineage. Advantages: can use on all species and fossils. Disadvantages: poor understanding of many lineages, especially using morphological features.
|
|
Lineage
|
Monophyletic group, genetic relationship between individuals and their ancestors.
|
|
Morphospecies Concept
|
Independent lineages are inferred via differences in morphological characteristics. Advantages: widely applicable to all organisms as well as fossils. Disadvantages: characters can be variable within a species and characters are subjective.
|
|
Ecological Species Concept
|
A set of organisms are adapted to a particular set of resources, called a niche, in the environment. According to this concept, populations form the discrete phenetic clusters that we recognize as species because the ecological and evolutionary processes controlling how resources are divided up tend to produce those clusters.
|
|
Temporal Isolation
|
May be able to reproduce and create zygotes, but never in the same place. Isolated from prospective mates. Ex: Spring field cricket and Fall field cricket.
|
|
Habitat Isolation
|
Occupy specific habitats that are different from prospective mates. ex: western and eastern meadowlark: occupy completely different parts of the country, although their gametes are compatible
|
|
Behavioral Isolation
|
Occupy same space as potential mates, but have certain behavioral traits that prevent mating. Ex. Two flowers that are pollinated by two different organisms.
|
|
Gametic Barriers
|
Gametes may not be compatible to create a zygote.
|
|
Mechanical Incompatibility
|
Gametes would be compatible, but they are unable to merge
|
|
Hybrid Viability
|
Can produce offspring, but the hybrid cannot survive
|
|
Hybrid Sterility
|
Can produce offspring, but the hybrid is sterile.
|
|
Cladogenesis
|
One species gives rise to two or more species, adds new branches to tree of life.
|
|
Anogenesis
|
One species gradually changes into another species over time, directional selection.
|
|
Allopatric Speciation
|
Populations become geographically isolated and, as gene flow ceases to occur, populations diverge genetically. Population in isolated area = allopatry.
|
|
Vicariance
|
A large population splits into two or more subpopulations due to geographic barriers. The populations become isolated and gene flow ceases. The populations are now subject to genetic drift and natural selection, and change accordingly.
|
|
Dispersal/Colonization
|
A small number of individuals from a population disperse, usually by accident, to a different habitat. They are more susceptible to genetic drift because of inbreeding. The different environment causes natural selection to accelerate adaptive changes.
|
|
Sympatric Speciation
|
Occurs without geographic isolation, so is more difficult to document than allopatric. Populations are in same geographic area and natural selection overwhelms gene flow. Ex: birds with small and large beaks based on what insects they eat.
|
|
Polyploidy
|
Xn, two or more homologs: Special form of sympatric speciation. Two mechanisms: Autoploidy (mutation causes doubling of chromosomes) and alloploidy (mutation in offspring causes polyploidy)
|
|
Punctuated Equilibrium
|
evolution is more sporadic with long periods of little change interspersed with periods of rapid evolution. Supported by fossil record.
|
|
Hybrid Zones
|
Area of hybrid population if viable offspring produced.
|
|
Gradualism
|
New species are continuously evolving. Supported by molecular genetics.
|
|
Evolutionary Developmental Biology
|
(Evo-Devo) Seeks to explain how new body types rapidly occur. Two main genetic mutation mechanisms: Gene Duplication and Changes in Gene Expression.
|
|
Homeotic (HOX) Genes
|
“Toolbox;” regulate 3-D development of animal body plans. Duplications may have allowed for more complex body plans, allows for random chance innovations to occur.
|
|
Gene Duplication creates:
|
Paralogs
|
|
Speciation creates:
|
Orthologs
|
|
Mutations affecting spatial/temporal expression of regulatory genes
|
Chicken and duck feet: Gremlin = webbed, lack of Gremlin = non-webbed.
|
|
Allometric Growth
|
different parts of body grow at different rates.
|
|
Paedomorphosis
|
juvenile traits are retained through adulthood
|
|
Phylogeny
|
Evolutionary History for a group of organisms, typically depicted as a tree.
|
|
Outgroup
|
Taxa that diverged prior to most ancient node of a tree.
|
|
Monophyletic Group
|
Clade. Ancestor and all its descendants.
|
|
Polyphyletic Group
|
Group of species with different common ancestors.
|
|
Paraphyletic Group
|
Group with common ancestor but only some of its descendants.
|
|
Polytomies
|
“Star Phylogenies.” More than two species emerge from a node due to adaptive radiation. Represents a period of rapid speciation.
|
|
Colonization Event
|
An adaptive radiation in which a habitat previously unoccupied by competitors is colonized by a species and that species quickly radiates to exploit new resources. Can also occur as an effect of mass extinction.
|
|
Morphological Innovation
|
A modification that allows new resources to be exploited by an organism.
|
|
Ingroup
|
clade that shares synapomorphy.
|
|
Fossil
|
physical trace of an organisms that lived in the past.
|
|
Biases of Fossil Record
|
Habitat, Taxonomic, Temporal, Abundance
|
|
Molecular Clock
|
Mutation rate is constant and should be linear. Most mutations are neutral and can be used to estimate time divergences for lineages. Can be used to examine how DNA has changed through time.
|
|
Cladistics
|
Utilizing Morphological and Genetic characteristics to estimate a phylogeny.
|
|
Synapomorphy
|
Shared derived trait that was not present in ancestor.
|
|
Symplesiomorphy
|
Common trait shared with ancestor.
|
|
Cladogram
|
considers pathways of evolution and selects the more plausible tree
|
|
Convergent Evolution
|
Same trait independently derived, analogous traits could throw off phylogeny estimations.
|
|
Reverse Mutations
|
base pair substitution can revert.
|
|
Hadean
|
formation of earth, primordial soup and probionts
|
|
Archean
|
Origin of life, radiation of prokaryotes.
|
|
Protozoic
|
origin and radiation of eukaryotes, simple, multicellular organisms.
|
|
Phanerozoic
|
radiation and diversification of multicellular organisms.
|
|
Paleozoic
|
Cambrian explosion, first vertebrates, first amphibians, reptiles, insects and gymnosperms. Permian extinction.
|
|
Mesozoic
|
First dinosaurs, mammals, gymnosperms radiate, first flowering plants. Mass extinction at end of Cretaceous.
|
|
Cenozoic
|
radiation of flowering plants and insects, radiation of mammals, appearance of hominids.
|