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Variance
Measures the entire distribution of the data
Standard Deviation
Measures the amount of variation from the mean
Standard Error
Describes how well your sample mean (n) reflects the mean of the entire population
What happens if your SE is high?
Your sample mean does not accurately reflect the population
What do overlapping error bars mean?
The means are not significantly different from each other
What do large gaps in error bars mean?
The means are significantly different from each other
What is homology?
Similarities resulting from common ancestry
What are the 3 types of homology?
Anatomical, Developmental, Molecular
What is convergent evolution?
Organisms independently adapt to similar environments in similar way, not due to common ancestry
What is analogous structures?
Structures that appear the same but from different ancestry
What is comparative embryology?
Reveals anatomical homologies not visible in adult organisms
What is molecular homology?
Similarities in DNA sequences or amino acid sequences due to common ancestry
What are fossil records?
Provides evidence of the extinction of species, the origin of new groups, and changes within groups over time
What is biogeography?
How species are distributed across geography
What is direct observation in evolution?
Measurable changes over short periods of time
What is continuous data?
non-discrete measurements
What are 2 examples of continuous data?
Height and weight
What is discrete data?
Distinct values or categories
What are 2 examples of discrete data?
number of kids, types of fruit
What is a null hypothesis
Counter to a hypothesis; a statement of "no effect"
What is Chi-Square Analysis?
How well the data fits experimental expectations; was the null hypothesis supported?
What kind of data can be used for Chi-Square Analysis
Discrete Data
How do you find degree of freedom?
(independent variables) - 1; (n-1)
What does it mean if Chi-Square value is less than critical value?
Observed and expected values are not significantly different from each other; null hypothesis is supported
What does it mean if Chi-Square value is greater than critical value?
Observed and expected values are significantly different from each other; null hypothesis is rejected
What is a species?
A group of individuals capable of interbreeding and producing viable, fertile offspring
What are some issues with BSC?
Fossilized organisms, Captivity vs wild, Molecular measures, Asexually reproducing species
What are the 2 ways new species are formed?
Allopatric and Sympatric
What is allopatric speciation?
A population is divided by a geological barrier and gene pools change over time
What is sympatric speciation?
One species becomes 2 or more species while living in the same geographic region via reproductive isolation
What are the 5 types of pre-zygotic isolation?
Habitat, temporal, behavioral, mechanical, gametic
What is habitat isolation (ecological)?
Live in same region, don't mate with each other
What is temporal isolation?
Mate different times of day or seasons
What is behavioral isolation?
Unique behaviors identify and attract same species
What is mechanical isolation?
Sex organs do not fit each other
What is gametic isolation?
Egg and sperm (gametes) do not fuse into zygote
What are the 3 types of post-zygotic isolation?
Reduced hybrid viability, reduced hybrid fertility, hybrid breakdown
What is reduced hybrid viability?
Hybrid offspring may have developmental abnormalities
What is reduced hybrid fertility?
Hybrids cannot reproduce
What is hybrid breakdown?
Hybrids okay/fertile first generation, but further generations weak/sterile
What is gradualism in evolution?
Rate of speciation is constant
What is punctual equilibrium?
Rate of speciation is not constant
What is adaptive radiation?
Many new species diversify rapidly from a common ancestor
What causes adaptive radiation?
Environment changes and leads to new resources and niches
What are the 3 modes of selection?
Directional, Stabilizing, Disruptive
What is directional selection?
Conditions favor individuals exhibiting one extreme of the trait/phenotype (mean shifts left or right)
What is stabilizing selection?
Favors the intermediate phenotype, both extremes are selected against (mean is the same, variance reduced)
What is disruptive selection?
Conditions favor individuals at both extremes of the phenotype over individuals with intermediate phenotypes
What is intersexual selection?
One sex chooses mates of the other sex based on certain characteristics (female choice)
What is intrasexual selection?
Members of the same sex compete with each other for access to the other sex (male competition)
What is sexual dimorphism?
Difference in size or appearance between sexes of the same species
What are 2 theories for sexual selection?
Good genes and sexy sons
What is LUCA
Last Universal Common Ancestor
What is some evidence of LUCA
“Right Hand” spiral DNA double helix, universal genetic code, DNA → RNA → Protein, 400 genes that code for same proteins
What was the Miller-Urey Experiment?
simulated early earth conditions, created amino acids and nucleotides
What is considered the first genetic material?
RNA b/c it can replicate and transfer information AND act as enzymes
How long does it take for biodiversity to recover from mass extinction?
5-100 million years
What are some effects of large scale mass extinction?
adaptive radiation b/c surviving species fill various niches
What is gene flow?
Individuals emigrating from one population to immigrating to another population; transferring genes from one population to another
What is genetic drift?
Chance events that cause allele frequencies to fluctuate from one generation to the next; associated with small populations
What is the founder effect?
Few individuals become isolated from a larger population and establish a new population; new population may differ in genetic diversity from source population
What is the bottleneck effect?
Severe drop in population that leads to certain alleles being over/under represented; next generation might have low genetic diversity
What is hybridization?
Mating of individuals from 2 species with incomplete reproductive barriers; gene flow between species
What are hybrid zones?
Region where 2 different species with incomplete reproductive barriers meet, mix, and mate
What are the 3 types of hybrid zones?
Reinforcement, fusion, stability
What is reinforced hybrid zones?
Reproductive zones are reinforced and hybrids are less fit than parents; gradually fewer hybrids are born
What is fusion hybrid zones?
Reproductive zones are fused together and gene flow between species increases; both species might fuse back into 1 species
What is stabilized hybrid zones?
Only a few hybrids are born each season; hybrid population becomes stable over time
What is a node on a cladogram?
Each branch point that represents a common ancestor
What is a clad in a cladogram?
A group of organisms with a common ancestor
What is an outgroup in a cladogram?
Organisms not in the group whose evolutionary relationships are being investigated
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