Biology Test Three Flashcards
Population
Group of organisms of the same species living together in the same geographic area.
Formed by a new allele making genetic changes in a species, thus making or changing a species to have an advantage.
Natural selection/ Adaptive evolution
Darwin
Environment selects favorable traits to have species be more adaptive and have higher reproduction rate.
Differential survival and reproduction of individuals in response to environmental pressure that leads to change in allele frequencies In a population over time.
Leads to adaptation
Acts on the phenotypes of organisms
Descent of modification
Darwin’s idea of natural selection was original contribution to this theory.
Combines the ideas that all living things are related sharing common ancestors in distant past and that organisms have changed over time.
Evolution
Change in allele frequencies in a population over time.
It’s the gradual change of species over time.
Nonadaptive evolution
Any change in allele frequency that does not by itself lead a population to become more adaptive to its environment
Caused by mutations.
Caused by genetic drift
Caused by gene flow
Mutations
Cause of Nonadaptive evolution
Introduces new alleles into a population.
Change in a gene frequency
Results in evolution.
Genetic drift
Cause of Nonadaptive evolution
Change in allele frequencies between generations that occurs purely by chance.
Completely random
Decreases the genetic diversity of a population
Two types: founder effect, bottleneck effect
Founder effect
Type of genetic drift
Small number of individuals or founders leave one population and establish a new population .
May have lower genetic diversity than original population.
Bottle neck effect
Type of genetic drift
Occurs when a population is suddenly reduced to a small number of individuals and alleles are lost from the population As a result
Less genetic diversity or extremely poor gene pool.
Can occur from natural causes
Gene flow
Cause of Nonadaptive evolution
Movement of alleles from one population to another
May increase genetic diversity of a population
Aka migration
Ex. Pollen being blown to a new destination.
Fit
Organisms fitness
Fitness
Relative ability of an organism to survive and reproduce in a particular environment.
Gene pool
Each population of any organism has its own particular collection of alleles.
Total collection of allele in a population.
Allele frequency
Within the gene pool
Relative proportion of an allele in a population.
Genetic diversity importance
Diverse gene pool gives a pop. More flexibility to survive in a changing environment
Improve evolutionary success.
Tiktaalik roseae
Between 4-9 ft long
Had fins, scales, a mobile neck, jointed wrist, finger like bones, flat skull, flexible neck, long sturdy ribs.
It was a predatory fish with sharp teeth.
Intermediate or transitional fossil between figs and tretrapods
Fossils
Preserved remains or impressions of a once living organism that provides a record of past life on earth.
Direct evidence of evolution.
Ways fossils are formed
Frozen, trapped, buried, leave imprint
Two kinds of fossil dating
Relative-determine age of fossil from its position relative to layer of rock or fossils of known age.
Deeper down they are buried, the older they are.
Radiometric- the rock layers formed from volcanic eruptions. Can be directly dated using Radiometric dating.
Used as a geological clock.
Ratio of radioactive elements of uranium and lead in the rock determine the age.
Fossil record
Group of fossils arranged in order of age providing evidence of changes in species over time.
Homology
And the three forms
Anatomical genetic DNA,or developmental similarity among organisms due to common ancestry.
3 forms:
Anatomical- number, order, and structure of the forelimb bones.
Embryological- similar e structures in vertebrates are evidence that all vertebrates share common ancestor.
DNA- closely related species have similar DNA inherited from ancestors.
Biological species concept
Defines a species as a population whose members can interbreed and produce fertile offspring.
Taxonomy
The process by which scientists systematically identify the name and classify organisms on the basis of a shared trait.
Taxonomists
Scientists who identify, name, and classify organisms.