GEOSCI 100 Lecture Notes - Lecture 20: Dog Type, Photosynthesis, Cyanobacteria
9 May 2018
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4-10-18
Photosynthesizing bacteria: Save the day
Review:
“The March of Progress” - this iconography of evolution as progress has been used over and over
in popular culture
→ However, this is NOT correct Lecture Slideshow Slide #19
→ gorillas did not become humans
→ humans did not evolve from gorillas
Does evolution imply an inevitable increase in
complexity, diversity and “superiority”?
•complexity and diversity can be scientifically
measured
→ superiority cannot be scientifically measured
because it depends on an individual’s perspective
*Evolution - the change in the frequency of heritable traits of a population over successive
generations
- There must be variability
- Variation + Natural Selection = Evolution
- Ex. giraffes used to have short necks but some had a little longer ones → over time, after
many generations have elapsed, their necks have become longer because of reproduction
*Natural Selection - the process whereby organisms better adapted to their environment tend to
survive and produce more offspring.
- Proposed by Charles Darwin
- Believed to be the main process that brings about evolution
*Artificial Selection - the breeding of plants and animals to produce desirable traits
- Organisms with the desired traits, such as size or taste, are artificially mated or
cross-pollinated with organisms with similar desired traits
- Ex. breeding two different dog types to produce a new dog type because you like
particular characteristics in the dogs that are bred
*Gregor Mendel - worked on pea flowers, discovering the fundamental laws of inheritance. He
deduced that genes come in pairs and are inherited as distinct units, one from each parent
Document Summary
The march of progress - this iconography of evolution as progress has been used over and over in popular culture. Does evolution imply an inevitable increase in complexity, diversity and superiority : complexity and diversity can be scientifically measured. Superiority cannot be scientifically measured because it depends on an individual"s perspective. *evolution - the change in the frequency of heritable traits of a population over successive generations. Ex. giraffes used to have short necks but some had a little longer ones over time, after many generations have elapsed, their necks have become longer because of reproduction. *natural selection - the process whereby organisms better adapted to their environment tend to survive and produce more offspring. Believed to be the main process that brings about evolution. *artificial selection - the breeding of plants and animals to produce desirable traits. Organisms with the desired traits, such as size or taste, are artificially mated or cross-pollinated with organisms with similar desired traits.
