ADAPTATION AND NATURAL SELECTION

LECTURE 4

Species Creation

• Species do not change

• Lineages do not spilt

• Each species is separately/independently created

• Earth and life is young

Descent with Modification

• Species change overtime ( Microevolution )

• Lineages spilt and diverge ( Speciation )

• New life forms derive from older life forms ( Macroevolution )

• All life forms are related ( Common Ancestory )

• Earth and life is old

Artificial Selection

Process where humans intentionally breed organisms to get an desired outcome of traits

• Natural Variation of species must be present for Artificial Selection to take place

  • However this can lead to domestication of organisms overtime ( ex: dogs )

Bighorn Sheep and Atlantic Cod

Human inventions such as hunting Bighorn Sheep and overfishing of Atlantic Cod, resulted to these traits these organism had to not be past down to next generation leading to change in traits being past on

Adaptive Selection

Process by which favorable traits become more common within a population due to its effect in increased fitness

• Soapberry Bugs adapted their beak sized by the types of soapberry seed present in their environments that changed due to human inversion

Adaptive Radiation

Process in which a single ancestral speices rapidaly evolves to different species over a short period of time

• Galapagos Finches are famous example of Adaptive Radiation that each adapted to their environments resulting to large variety of beak sized within the population

Natural Selection

The statical difference in reproductive success among organism

• Some individuals are able to reproduce more than other due to their inherited traits

Evolution

Evolution itself is non-random ( will favor traits that increase fitness and survivability )

• However it is not progressive ( not goal-orientated )

Sticklebacks

Sticklebacks underwent evolution due to environmental changes

• Saltwater Sticklebacks typically are fully armored with many pelvic spines to defend against predators

• Freshwater Sticklebacks do not have as much armor, thus have reduced pelvic structures/spines ( possibly due to having less predators )

Alaska Fish

Same process occurred for Alaska Fish, and by breeding fishes with pelvic structures with those with reduced pelvic structures found that the pelvic structure gene is dominant

Macroevolution

Large scale evolutionary changes over long periods of time

Vestigal Structures

Refers to reduction in characteristic due to lack of use

Adaptations

All environments present problems for an organisms, in which are solved through adaptations ( which arise through natural selection favoring some traits over others in the name of fitness/survival )

• 3 types being ( physiological, behavioral, genetic )

Fitness

Reproductive success in total number of offspring an individual leaves behide