Life on Earth: What are its origins? (EXAM 1) Flashcards
Biodiversity
defined as “Life on Earth”. Includes all living (biotic) organisms and their complex interactions with each other and with the non-living (abiotic) aspects of their enviornment
of species of fish
30,000
of species of birds
10,000
of species of mammals
5,000
of species of plants
350,000
of species of reptiles
8,200
of species of amphibians
6,200
of species of insects
over 1 million
beetles are the largest group
of species of fungi
100,000
Species
defined as an individual organism that is assigned a name (common name and scientific name)
Speciation
occurs via the process of evolution
Evolution
when species descend with modification, from ancestral species over time
- Change + Time=difference=advantage=adaptation/survival
Macroevolution
change above the species level
Ex) birds evolved from reptiles
Microevolution
change within a gene pool over time
Ex) darwins finches
gene pool
genetic material within a population
Coevolution
mutual influence between two species, where each species exerts selective pressure effecting each others evolution
Ex) predator vs prey
Mutation
random changes in DNA to produce variation within populations; also crossing over occurs during meiosis
mutation frequency
1 in 10 with 1 in 1000 mutations being beneficial
Sources of evolutionary variation
bacterial symbionts and viruses
Natural Selection
a process by which unfavorable variations are “weeded out” and greatly improves the survival of offspring (survival of the fittest)
Charles Darwin
1809-1882
went to galapagos island on the HMS Beagle, studied finches, known for natural selection
Alfred Russel Wallace
1823-1913
also known for natural selection
Directional Selection
changing environmental conditions causing shifts in population
Stabilizing Selection
elimination of individuals at extremes of population favoring the average
Diversifying or Disruptive Selection
individuals at extremes are favored due to environmental stress
Gene Flow
movement or exchange of genetic material between populations= isolated segments of a large population interact
Genetic Drift
genetic change due to chance events (natural or human) that result in small population size creating a genetic bottleneck and resulting in the elimination of beneficial adaptation
Founder Effect
the establishment of a new population by a small number of individuals that carry a small fraction of the original populations genetic variation
