Ecology Notes

Topics: Evolution, Species, Bacteria Pages: 22 (3797 words) Published: March 27, 2013
Evolution as a theory
* Theory- in science, a well substantiated explanation of some aspect of the natural world Evolution- the accumulation of inherited genetic changes within populations over generations * Does not refer to changes that occur in an individual within its lifetime * Not limited to speciation that may only occur over long periods of time * Can occur over a few generations, and is most commonly expressed as an adaptation to a changing environment or the change in allele frequencies of genes * Adaption- a modification that improves the changes of survival and reproductive success in a given environment * Natural selection

* Variation
* Overproduction
* Limits on population growth
* Differential reproductive success
* Gregor Mendel- Mendel’s principles of segregation and independent assortment Modern synthesis
* Integration between the units of evolution and the mechanism of evolution * Mutation- a permanent change in a cell’s DNA including: * Nucleotide sequences
* Alteration of gene positions
* Gene loss or duplication
* Insertion of foreign sequences
Modern synthesis- unification and development of several branches of biology that previously had little in common particularly * Paleontology
* Systematics
* Developmental biology
* Behavioral
* Ecology
Evidence for evolution
* Fossil record
* Biogeography
* Homoplasy
* Selective breeding
* Homologies
* Experiment evidence of adaptation
Fossil record
* Complex organisms in younger rocks
* Simple organism in older rocks
* Study of geographical distribution of extinct and modern species * Isolated continents
Homoplasy (similar form- different origin)
* Homoplastic- features are similar features not inherited from a common ancestor * May adapt in similar ways to similar environments; convergent evolution * Homoplastic features- features with similar functions that evolved independently in distantly related organisms Selective breeding/artificial selection

* Programs and procedures designed to modify traits in other species * Made possible by:
* Genetic variation- overproduction
* Limits on population growth
* Differential reproductive success
* Breeders choose parents in artificial selection
* Breeders choose desirable phenotype
* Fundamental similarity due to descent
Anatomical homology
* Homologous features- similar features with different functions evolved from the same structure in a common recent ancestor * Vestigial structures- remnants of more developed structures that were present and functional in common ancestors Developmental homology

* Species that differs as adults
* Evolution is a conservative process, it builds on the past Molecular homology
* Similar/same form
* All living species use DNA
Experimental evidence of adaptation

Chapter 22- Speciation and macroevolution
* Understand how the theory of evolution and natural selection explains biodiversity * Know micro and macro evolution
* Know 4 species concepts and when each is useful
* Know reproductive isolating mechanisms
* 5 pre zygotic and 3 post zygotic; and examples
* Know allopatric and sympatric speciation
* Know 2 models of rate of evolutionary novalties and diversity * Allometric growth
* Paedomorphisis
* Adaptive radiation
* Extinction
Evolution- the accumulation of inherited changes within populations over generations * Can occur over a few generations and is most commonly expressed in an adaptation to a changing environment or the changes in allele frequencies of genes * Adaptation- a change in structure, physiology, or behavior that increases an organisms fitness in a given environment Micro and macro

* Micro- changes in allele or genotype frequencies that...
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