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Biology 2
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Taxonomy
classification of organisms into groups
What are the characteristics of mammalia?
mammory glands and hair
Evolution
change in gene/allele frequency overtime within a population
DNA
code for how to synthesize a protein
Chromosome
one big long strand of DNA
Homologous
23 chromosomes that are identical
Genes
section of DNA codes for a specific protein
Alleles
alternate version of DNA
Dominant
a gene that is always expressed
Recessive
a gene only expressed if NO dominant is present
Artificial Selection
selecting and breeding individuals that posses desired traits, the human does the selecting.
Comparative Anatomy
anatomical similarities between many species gives signs of common descent
Homology
similarity in characteristics that results from common ancestry
Homologous Structures
anatomical similarities in different organisms
Vestigal Organs
structures of marginal or no importance to the organism
Genotype
combination of alleles
Phenotype
how that combination of alleles are expressed
Evolution by natural selection
1. there is much variation in a population
2. much of this variation is heritable
3. most organisms produce more offspring than
survive to reproduce
4. the individuals that survive are the ones that are
best fit for that environment
5. the environment is constantly changing
Population
group of individuals of the same species living in the same place at the same time
Gene Pool
total collection of genes in a population at any one time
Microevolution
relative frequencies of alleles in a population change over a number of generations causing a change in gene pool
3 random components of sexual reproduction
independent orientation of homologous chromosomes
fertilization
crossing over
What is the ultimate source of genetic variation?
mutation
What is the source of most genetic variation in a population that reproduces sexually?
unique combination of alleles
3 main causes of evolutionary change
natural selection
genetic drift
gene flow
Gene flow
transfer of alleles from one population to another as a result of the movement of individuals
Adaptive evolution
evolution that results in a better fit between organisms and their environment
Sexual Dimorphism
difference in appearence
Balancing selection
natural selection maintains stable frequencies of 2 or more phenotypic forms in a population
Frequency dependent selection
maintains 2 different phenotypic forms in a population
Selection pressure
whatever is selecting for and against individuals
Evolutionary fitness
ability to survive and reproduce
How do you measure fitness?
by the production of fertile offspring
3 key points to natural selection
population event
acts on heritable traits
not goal directed
Where does genetic variability come from?
ultimate- mutation
proximal- sexual reproduction
Environmental selection pressures
stressful environment
predation
competition
Morphology
means appearence
Non-selection influences
gene flow
genetic drift
Genetic drift
change in gene/allele frequency of a small population simply by chance
Example of genetic drift
bottleneck effect
founder effect
Author
Anonymous
ID
66926
Card Set
Biology 2
Description
Evolution and Genetics
Updated
2011-02-17T04:05:24Z
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