Lecture 2 Flashcards
What is microevolution?
The change in allele frequencies over time within a population
What is macroevolution?
Evolution above the scale of species
What are the alternative explanations for diversity/change/adaptation?
- Evolution
- Transformism
- Creationism
What does evolution explain?
With evolution, all species have a common origin, and change and diversity through time
What does transformism explain?
With transformism, species have separate origins, and species change but don’t diversity
What does creationism explain?
With creationism, many postulate separate creations of species and the immutability of species
How is microevolution observed?
- Direct observation
- Field experiments
- Transformation experiments
How is macroevolution observed?
- Fossil record
- Biogeography distributions (i.e. closely related species often occur in the same or in proximate biogeographic regions - hiearchial nested relationships of species)
What is the definition of homology?
A homology is a shared feature that is inherited from a common ancestor (e.g. vertebrae forelimbs, universal genetic code, embryological stages)
What is the significance of homology?
Homologous structures are evidence of both evolution and the theory that organisms descended from a common ancestor
What is the definition of a vestigial structure?
A vestigial structure is an anatomical features or behavior that no longer seems to have a purpose in the current form of an organism of the given species; these vestigial structures were once important in function at one point in time
What is the significance of a vestigial structure?
Vestigial structures are evidence of evolution, as well as descent with modification
What is the definition of a pseudogene?
A pseudogene is an imperfect duplicate/copy of a functional gene that lost some or all functionality of a complete gene (e.g. GULO pseudogene synthesizes vitamin C)
What is the definition of a suboptimal design?
A suboptimal design includes features not perfect it from an engineering perspective (e.g. the crossing of the air pathway with the food pathway)
What is the significance of a suboptimal design?
Suboptimal designs are evidence of descent with modification
What is the definition of natural selection?
Natural selection is differential survivorship and reproduction due to a heritable trait
What is the significance of natural selection?
Natural selection is one of the major forces shaping the course of evolution; it is the only evolutionary for generating adaptation in a population
A trait is called an adaptation when what factors occur?
- Improve survivorship and reproduction
- Arose by natural selection
What is the definition of convergence?
Convergent evolution is the process whereby organisms not closely related independently evolve similar traits as a result of having to adapt to similar environments (e.g. the body plan in placental and marsupial mammals)
What is the significance of convergence?
Convergence provide evidence of shared ancestry and similar biological needs (i.e. independently evolved solution to a similar problem)
What is the definition of vicariance?
The geographical separation of a population resulting in a pair of closely related species
What is the significance of vicariance?
Vicariance is evidence of the separation of biological lineages via continental drift
Explain how human brachial clefts are a vestigial structure:
Human brachial clefts are homologous to gills - when brachial arches form in early embryonic development but fail to obliterate, brachial cysts form
