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Study Guide: Exam 1
Fossils |
look at ancient organisms in life |
What is the most reliable proof of evolution? |
Fossils |
How is the age of fossils determined? |
by geology strata (layers) in the earth |
Relative Age |
Determined by strata |
Absolute Age |
Determined by Carbon Dating |
What does carbon dating compare? |
Radioactive C14 vs. normal C12 |
14 C |
radioactive decays after death |
12 C |
normal carbon left over after death |
Half Life |
use half life of carbon to calculate the age of fossils |
Eras |
Consistent boundaries in strata |
Precambrian |
most of Earth's history Formation of Solar System Origin of life single cells start multicell |
Paleozoic Era |
Cambrian Carbinuferous Pangea |
Mesozoic |
Pangea broke up Reptiles flowering plants... meteor hit, large animals extinct |
Cenozoic Era |
Current continent position Age of mamals diversification Humans |
Oxygen |
At first a poison Organisms evolved to tolerate and require it |
Fact of evolution |
change in species over time |
Theory of Evolution |
Natural Selection change in species/ new species |
Darwin's Theory of Evolution (3) |
1) Populations change over time 2) Organisms multiply faster than their resources 3) Offspring tend to resemble parents |
Artificial Selection |
describes intentional breeding for certain traits, or combination of traits. |
Natural Selection |
The next generation resembles those who did best |
Fitness |
The likeliness that a organism has for reproduction |
Adaptation |
To become well suited A trait that is well suited |
Genotype |
set of all genes in one individual |
Phenotype |
Sets of traits in an individual |
Mutation |
gene that never existed before |
Components of Evolution |
Variation in population selection on variation inheritance of variation time |
Teleology |
The idea that natural processes have a goal or purpose |
Blending Inheritance |
offspring traits are the average of their parents variation would be lost |
Mendellian Genentics |
New combinations of genes produce new trait variation |
Population Genetics |
Alleles in a population |
Quantitative Genetics |
Phenotypes vary continuously |
Haploid |
One copy of each gene |
Diploid |
Two copies of each gene |
Polyploid |
Multiple copy |
Gene Pool |
Collection of all alleles in a population |
Stabilizing Selection |
average traits are the most successful |
Directional Selection |
Most successful on on extreme |
Disruptive Selection |
Extremes are most fit |
Genetic Drift |
chance differences in alleles Alleles are lost Reduces genetic variation Smaller population, more reduced |
Limitations of Natural Selection |
Trade Offs Small changes are viable What if no suitable varient exists? |
Allopatric Speciation |
requires genetic isolation geographic separation |
Sympatric Speciation |
Postzygotic reproductive variables (hybrids) |
Cladogenesis |
Creation of new clade |
Clade |
A group consisting of an ancestor |
Theory of Common Decent |
all species belong to a big family tree |
Phylogeny |
History of how species desended |
Phylogenetic Tree |
Graphical representation of phylogeny |
Ancestral Trait |
shared from inheritance |
Derived Trait |
Trait different from ancestor |
Homologous Trait |
shared by species descended from a common ancestor |
Convergent Evolution |
Independently evolved traits that look similar |
Parsimony |
Assume the least number of changes |
Cooperation |
An act or trait of one individual that benefits others |
Altruism |
Providing a benefit to another while adding cost to one's self |
Mutualism |
Cooperation between different species |