2: Evolution and Natural Selection Flashcards
What is the one thing constant in biological history
change
Are dog breeds different species
no, just significant variability, artificial selection
Who is John Ray
- naturalist
- species concept
-“group of organisms that can successfully reproduce amongst themselves”
Who is Linneaus
- taxonomy and binomial nomenclature (did believe in fixity)… gave us names homo sapiens
Who was George Buffon
“species adapt slightly to new conditions” - vestigial organs and limbs… had undergone changes over time
- natural history of man, biological relationship with ape
- old earth age
Who is Lamark
inheritance of acquired characteristics
Who is Charles Darwin
- Voyage of the HMS Beagle (1832-1836)
- Geographic correlation between the fossil record and living organisms
- Ex: megatherium - extinct species of sloths….. Glyptodon extinct relative of armadillo
- Galapagos island, finches… habitat bill shape and diet…
- Galapagos tortoises - domed shells in wet, dry - shells for taller necks
- Evolutionary arms race between tortoise and cacti….
What are the 6 Fundamental Premises of Natural selection
- More offspring produced by a species than can be supported by naturally available food sources
- Within any one species there exists a significant amount of biological/genetic variability
- Individuals with advantageous traits will have an edge over other members of their species in terms of their ability to survive longer
- Those individuals with traits that increase their chance of living longer are more likely to reach the age at which they will begin reproducing and are more likely to contribute offspring to subsequent generations… therefore those traits that gave these individuals this advantage will be passed on to their offspring giving them the same advantage
- Those traits that are advantageous under current environmental conditions will tend to be passed on
6.Over long periods of time, accumulated changes within a species will eventually result in new species = speciation
Starting with subspecies… eventual separate species… eventually different genera
Who is Thomas Malthus
Essay on principles of populations - animal pops tend to increase exponentially while food supplies remains stable
What is an individual’s reproductive success generally dictated by
An individual’s reproductive success is generally dictated by reproductive potential or fitness: products of their ability to adapt (or not) to specific environmental conditions
What aids the process of speciation
The process of speciation often aided by geographic isolation
What are other fundamental components of evolutionary process
- Other fundamental components of evolutionary process
Of the inherent variability in traits in a species… many are neutral traits
*dependent on environment - Natural selection only acts on the variation that already exists in a species
Selects from what’s already there. - Natural selection can only act on genetic variability
- Natural selection can only play a role in the selection of traits that affect the reproductive success of an individual
Does evolution move in a specific, purposeful direction
no
What are some misconceptions of evolution
- Moving in a specific, purposeful direction…..
- It’s a process, not good or bad
What is the grandmother hypothesis
human children are very dependent, childbearing in humans is dangerous… reproductive success increase if live beyond producing offspring time and energy in increasing survival potential of offspring and grandchildren
