Evolution Flashcards
Evolution
The process in which significant changes in the inheritable traits (i.e. genes) of a species occur over time.
Variation
a different or distinct form or version of something.
Selection
mechanism that drives the evolution of a species
Recombination
New combinations of alleles as frequencies and favourability changes
Mutations
Genetic variations different than the norm
Gregor Mendel
Answered the questions of heredity left in Darwin’s work
Immutable
Unchangeable.
The age of the Earth
4.54 billion years old
Radiometric dating
Tool used to determine the age of the earth
Fossil records
fossils can be dated; show previous evolutionary forms of modern animals
Excess offspring
an organism produces more offspring to accomodate for the death rate
Spontaneous generation
Life comes from non-living things.
Creationism
Creator made things as we see now
Catastrophism
natural disasters killed off old species (explaining fossils)
Jean-Baptiste Lamarck
The Theory of Acquired Characteristics; if an organism changes during its life, those changes are passed down (e.g. bodybuilder passes down muscles). Wrong but close
Charles Darwin
First to theorize evolution but could not explain heredity.
Darwin’s voyage
5 year voyage started in 1831; goal was to observe, collect and record specimens
Darwin’s finches
Different variations of the same species due to environmental factors
Galapagos Islands
One of Darwin’s stops during his voyage; he found each island has different variations of the tortoise, depending on the environment
Heredity
passing on of physical or mental characteristics genetically from one generation to another.
Punctuated equilibrium
After the initial burst of evolution, species do not change significantly over long periods of time.
Species
Different variations of a genus
Pentadactyl limb
five-fingered limb possessed by many different species (whale, bat, human, mole, etc.)
Homologous structures
Similar in origin but different in functions (ex: dolphin flipper and human hand)
Divergent evolution
Ancestral line started out similar but diverged in different directions, towards different structures or functions
Common ancestor
ancestor shared by different animals
Analogous structures
similar in function but different in origin (ex: wings of birds and butterflies)
Convergent evolution
different ancestors converge towards a similar function or structure
Embryology
Study of embryos and their development
Vestigial structures
structures that are reduced forms of structures that were functional in the animal’s ancestor but are no longer useful/effective (ex: tiny detached pelvic bone in whales)
DNA
a clue to how closely related different organisms are
Fitness
the lifetime reproductive success of an individual
Allele frequency
frequency (how often) alleles are present in a population
Founder effect
a few individuals from a large population leave and form a new population, resulting in new allele frequency
Bottleneck effect
Type of genetic drift; dramatic but temporary reduction in population size, resulting in significant genetic drift.
Genetic drift
change in the genetic makeup of a population, resulting from chance
Gene flow
net movement of alleles from one population to another (i.e. migration)
Migration
Example of gene flow
Natural selection
shows that certain alleles are more successful than others when they enhance the phenotype of the individual and contribute to their reproductive success.
Stabilizing selection
Type of natural selection; the most common phenotype is the most favoured by the environment
Directional selection
Type of natural selection; the environment favours one extreme of a trait
Disruptive selection
Type of natural selection; the environment favours both extremes of a trait
Sexual selection
favours the selection of any trait that influence the mating success of an organism; produces traits that are ONLY beneficial for mating and are otherwise detrimental
Sexual dimorphism
obvious differences in the physical appearance between males and females (ex: bright feathers)
Female choice
Type of sexual selection
Male-male competition
Type of sexual selection
Speciation
rapid bursts of evolution of species in a short amount of time; normally occur in small isolated populations
