EVolution , Bio

accumulation of intended changes within populations over time

acts to remove the negative traits from a population until it disappears.

-elimination of the least fit, affects phenotype

Galapagos islands to South American land

- overproduction

-population growth is limited

-variation

-differential reproductive success

each species has ability to produce copious offsrping, yet populations stay constant

resources are limited

-exists a struggle when individuals/populations compete for resources

individuals within a population exhibit inherited variations

individuals that posses the most favorable traits to survive are more likely to pass them to their offspring

earth changed slowly over time due to geological processes

population growth is not always desirable

-documented fossil discoveries

-shared extinction occurred

suggested that living species change over time

-Allopatric

-Sympatric

-Parapatric

populations of a species became geographically isolated

-over time populations will become genetically different in response to their habitats, gene flow ceases

populations of a species that share same habitat become reproductively isolated from each other

-can happen by just finding a new niche.

speciations when populations are seperated by an extreme change in habitat

-makes them interbreed at different times

-mutations

-gene flow

-genetic drift

-nonrandom mating

-natural selection

alteration in an organisms DNA.

-no harmful effect

-beneficial or adoptive mutations are indispensible to evolution

movement of alleles from one population to another

-occurs when individuals move between populations

-or when populations species joins another

chance alteration of gene frequencies

-strongly affects small population

ex) bottle neck and founder effect

-occurs when one member is not equally to mate with any other member in population

-includes sexual selection

some individuals will be better at surviving in the environment than other thus passing on their traits.

caused by changing environment resulting in a small population of survivors

-as populations rebuilds, new gene pool may develop differing from old.

caused by small groups of populations called colonies, formed due to isolation.

if an individual with a certain gene is as reproductively fit as others in population than the gene will persist with some frequency from generation to generation

-stabilizing

-directional

-disruptive

-infant will way low or very high birth weights have a higher rate of mortality

-diversity decreased. intermediates favored

changes in environmental conditions focuses on one extreme

-favors one extreme

environmental conditions favors each extreme

-genetic diversity

-may lead to development of new species

favors both extremes over intermediate trait

-geographical

-ecological

• -temporal
• ----------------

• -behavioral
• - mechanical
• -gamete

individuals of 2 populations cannot interbreed if they live in different places

even if they live in same place, they cannot mate if thhey dont have in contact

even if they come in contact, they cant breed if they breed at different times

even if they breed same time they wont mate if they are not attracted to one anohter.

even if they are attracted to one another they cannot mate if they arent physically compatible

even if they are physically compatible an embryo will not form if the egg and sperm do not fuse properly

-Hybrid inviability

- hybrid sterility

-hybrid breakdown

occurs when zygote dies before reaching maturity

occurs when unequal #'s of chromosomes causes breakdown during meiosis and not allowing hybrid to product viable egg or sperm

F2, F3 generation is defective and unable to reproduce

-homologous textures: derive from same structure in common ancestor

-vestigial structures: remnants of structure

- Universally of genetic code

-cell theory: cells come from other cells