2: Evolution and Natural Selection

Question 1

What is the one thing constant in biological history

Answer 1

change

Question 2

Are dog breeds different species

Answer 2

no, just significant variability, artificial selection

Question 3

Who is John Ray

Answer 3

• naturalist
• species concept
  -“group of organisms that can successfully reproduce amongst themselves”

Question 4

Who is Linneaus

Answer 4

• taxonomy and binomial nomenclature (did believe in fixity)… gave us names homo sapiens

Question 5

Who was George Buffon

Answer 5

“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

Question 6

Who is Lamark

Answer 6

inheritance of acquired characteristics

Question 7

Who is Charles Darwin

Answer 7

• 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….

Question 8

What are the 6 Fundamental Premises of Natural selection

Answer 8

1. More offspring produced by a species than can be supported by naturally available food sources
2. Within any one species there exists a significant amount of biological/genetic variability
3. Individuals with advantageous traits will have an edge over other members of their species in terms of their ability to survive longer
4. 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
5. 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

Question 9

Who is Thomas Malthus

Answer 9

Essay on principles of populations - animal pops tend to increase exponentially while food supplies remains stable

Question 10

What is an individual’s reproductive success generally dictated by

Answer 10

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

Question 11

What aids the process of speciation

Answer 11

The process of speciation often aided by geographic isolation

Question 12

What are other fundamental components of evolutionary process

Answer 12

1. Other fundamental components of evolutionary process
   Of the inherent variability in traits in a species… many are neutral traits
   *dependent on environment
2. Natural selection only acts on the variation that already exists in a species
   Selects from what’s already there.
3. Natural selection can only act on genetic variability
4. Natural selection can only play a role in the selection of traits that affect the reproductive success of an individual

Question 13

Does evolution move in a specific, purposeful direction

Answer 13

no

Question 14

What are some misconceptions of evolution

Answer 14

• Moving in a specific, purposeful direction…..
• It’s a process, not good or bad

Question 15

What is the grandmother hypothesis

Answer 15

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

Question 16

What is micro evolution

Answer 16

evolutionary change within a species or small group of organisms, especially over a short period.

Question 17

What is Macro evolution

Answer 17

longer changes….speciation

Question 18

What is the traditional view on speciation occurs

Answer 18

species spread into variety of environments and either through geographic barriers or just sheer distance, different populations fail to continue to interbreed and so very slowly and gradually diverge into new species (phyletic gradualism)… doesn’t follow fossil record

Question 19

What is punctuated Equilibrium

Answer 19

long periods of little change, then abrupt change (what we tend to see in fossil records)

Question 20

What is replacement evolution

Answer 20

• parent species goes extinct and replaced by daughter species
• called anagenesis, quite rare
• occurs when all members of species are together in a contained environment

Question 21

What is divergent evolution

Answer 21

• Both species continue to exist
• Cladogenesis - results from species occurring as separate populations can be subject to different selective pressures and is the most common way that evolution occurs