Natural selection: the differential survival and reproduction of individuals within a population
Biogeography: the geographic distribution of species, suggested to Darwin that organisms evolve from common ancestors
Comparative anatomy: is the comparison of body structures in different species
Homology: is the similarity in characteristics that result from common ancestry
Molecular biology: comparisons of DNA and amino acid sequences between different organisms reveal evolutionary relationships
Population: a group of individuals of the same species living in the same place at the same time
Evolution: the change in heritable traits in a population over generations
Gene Pool: the total collection of genes in a population at any one time
Microevolution: a change in the relative frequencies of alleles in a gene pool over time
Population genetics: studies how populations change genetically over time
Reading Journal: 1) What is artificial selection? artificial selection is a process in which humans have modified other species by selecting and breeding individuals that possess desired traits.
2) Who are paleontologists? they are scientists who basically study fossils.
3) What is the Hardy-Weinburg equilibrium? The principle that the frequency of each allele in the gene pool will remain constant unless other factors are operating.
Five Facts: 1) In the mid-1700s, the study of fossils revealed fossil forms in layers of sedimentary rock that differed from current life forms.
2) Fossil records is the sequence in which fossils appear within layers of sedimentary rocks. They provide some of the strongest evidence of evolution.
3) Vestigial organs are structures that are of marginal or no importance to the organisms. They are remnants of structures that served important functions in the organism's ancestors.
4) Darwin's boldest hypothesis is that all life-forms are related.
5) In The Origin of Species, Darwin provided evidence that life on Earth has evolved over time, and natural selection was the primary mechanism for the change.
Adaptations are inherited characteristics that enhance organism's ability to survive and reproduce in a particular environment. In natural selection individuals that are well suited to the environment tend to leave more offspring, while those who are not well suited eventually decline. In Darwin's theory of evolution, living species are descended from earlier life-forms that differed from present day organisms. There has been evidence of natural selection in the populations of birds, insects, and other organisms. Fossil records are able to reveal the historical sequence that organisms have evolved and many fossils linking ancestral species with those living today.
Evidence of evolution comes from sources of biogeography, molecular biology, comparative anatomy, etc. Homologous structures and DNA sequences also provide evidence of evolutionary relationships.
Allele frequencies change due to natural selection, genetic drift, and gene flow. The bottle neck effect occurs when a population’s size is reduced for at least one generation. Founder's effect occurs when a new colony is started by a few members of the original population. The new colony may have a reduced genetic variation from the original population and a non-random sample of the genes in the original population. They both may lead to genetic drift as well.
Sexual selection leads to the evolution of secondary sex characteristics, which give individuals an advantage in mating. An example include the male peacock showing his big and colorful feathers.
There has been much concern over the evolution of antibiotic resistance in bacteria. An antibiotic resistance results from excessive or incorrect use of antibiotics.
Many may think that natural selection fashions perfect organisms, but it does not. Selection can only act on existing variations. Evolution is limited by historical constraints; adaptations are often compromises; and chance, natural selection, and the environment interact.
This is an example of human population in North America. People are most likely to choose mates locally. For humans and other species, individuals in one population are generally more closely related than to other members in other populations.
Youtube video Natural selection:
http://www.youtube.com/watch?v=oCXzcPNsqGA
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