Mechanisms of Biological Evolution Flashcards
Lamarckian Inheritance
The idea that characteristics an organism acquires during its lifetime can be passed on to its offspring.
Darwinian Evolution
Populations (rather than individuals) change over time due to natural selection.
How does paleontology support the theory of evolution?
New layers of ground and fossil form on top of old layers, forming a sort of biological timeline.
How does biogeography support the theory of evolution?
The way that species are distributed across Earth suggests a common ancestor.
How does comparative anatomy support the theory of evolution?
Many organisms share similar structures at some point during embryonic development. Also, many organisms have homologous anatomical structures.
How does molecular biology support the theory of evolution?
Organisms with similar DNA will have a common ancestor from long ago.
Punctuated equilibrium
Long periods of stability with abrupt episodes of speciation.
Molecular clocks
Compare the number of nucleotide differences against dates of evolutionary events.
Hardy-Weinberg Equation (5 parts)
1.) Random mating
2.) Large population size
3.) No migration between populations
4.) No mutations
5.) No natural selection
Evolutionary agent
Any force that alters the genetic structure of a population
Genetic drift
Random loss of individuals and the alleles they possess
Population bottleneck
An event that drastically reduces the size of a population
Founder effect
When a small group leaves the main population to form a new population
Behavioral adaptation
Organism changes how it interacts with its environmental surroundings
Physiological adaptation
Organism changes how its body functions internally
Structural adaptation
Organism changes at least one of its physical features
Analogous structures
Traits that are similar among different organisms who did not share a common ancestor, but needed to solve a shared environmental problem.
Convergent evolution
When species occupy similar ecological niches and adapt in similar ways in response to selective pressures.
Homologous structures
Similar structures, but different functions among animals that share the same common ancestor.
Directional selection
When one extreme variation of a trait is selected for
Disruptive selection
When both extreme variations of a trait are selected for
Stabilizing selection
The middle variation of a trait is selected for
Speciation
A species splits into 2 or more new species
Allopatric speciation
The division of an original population by a physical barrier
Sympatric speciation
The division of an original population by experiencing different ecological niches or genetic changes
Prezygotic isolation
Different species cannot create offspring by preventing their gametes to form a zygote
Postzygotic isolation
Occurs after fertilization and results in reduced zygote viability or offspring with lower fitness
Divergent evolution
Species gradually becomes different from its ancestors over time
Parallel evolution
Two unrelated species in the same environment evolve together, forming similar characteristics
