Exam 1 Flashcards
Allopatric speciation
Speciation due to geographic isolation
Most prevalent method for cladogenesis
Evolution is…
Descent with modification
Microevolution
Changes in a single gene in a population over time
Macroevolution
Formation of a new species: several changes over time
Convergent evolution
When different organisms independently evolve similar traits
Homologous traits
Structures that are similar due to being derived from the same ancestral trait
molecular homologous
Homologous in the molecular features of organisms
Developmental homologous
Homologous in the development pathways of organisms
anatomical homologous
homologous anatomical features of organisms
Georges Buffon
Proposed that lifeforms change over time
Jean-Baptiste Lamarck
Proposed inheritance of acquired characteristics; believed in “scala natura” or the Great Chain of Being
Erasmus Darwin
Believed there was a common ancestor to all life forms and that offspring inherit features from parents.
Charles Darwin
Gave most convincing, complete argument for evolution in his book “On the Origin of Species”; proposed mechanism for how evolution occurs (natural selection)
Alfred Russell Wallace
Contemporary of Darwin with the same ideas, just slightly less fleshed out.
Hardy-Weinberg Equation
Relates allele and genotype frequency in a population.
Hardy-Weinberg equilibrium is unbroken, allowing you to predict genotype frequencies under the following conditions
- No new mutations
- Random mating
- No migration between populations
- Large population size
- No natural selection
Evolution can be the result of the following factors
- Appearance of new genetic variation in a population
- Non-random mating
- Migration between populations
- Genetic drift (especially in small populations)
- Natural selection
5 mechanisms of microevolution
- Appearance of new genetic variation in a population (mutations)
- Non-random mating
- Migration between populations (gene flow)
- Genetic drift (including bottlenecks and founder effect)
- Natural selection
Anagenesis
Directional selection (changes within a lineage)
Cladogenesis
Disruptive or diversifying selection (creation of new lineage)
Stasigenesis
Stabilizing selection (no changes within a lineage)
Intrasexual selection
Competition between members of the same sex (tends to promote weaponry, badges and large body size)
Intersexual selection
Mate choice by members of the opposite sex (tends to promote elaborate mating rituals, ornaments and displays)
Biological species concept
Species is a group of individuals whose members have potential to interbreed with one another in nature to produce viable, fertile offspring
Prezygotic reproductive isolating mechanisms
Before fertilization of the egg
- Habitat isolation (geographical barriers prevent contact)
- Temporal isolation (reproduce at different time of the day or year)
Sympatric speciation
Speciation that happens in overlapping geographies
Hybrid zones
Zones where 2 populations can interbreed
Punctuated equilibrium
hypothesis that evolutionary development is marked by isolated episodes of rapid speciation between long periods of little or no change
Adaptive radiation
the diversification of a group of organisms into forms filling different ecological niches
-Favored during founder events and when there is abundant resources.
Prokaryotes
Mostly unicellular; lack nuclei; reproduce via binary fission; divided into two domains- archaea and bacteria; smaller than eukaryotes; lacks most organelles; come in a variety of shapes
