Bio Exam II Study Guide
Terms
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- Describe genotype Vs. pheotype of an individual organism
- Genotype is the genetic makeup, and phenotype is the measurable, physical traits. The genontype determines the phenotype.
- definition of allele
- variant form of a gene
- definition gene pool
- total # of genes in a population at any one time
- definition of "gene flow"
- genetic exchange due to migration of fertile individuals or gametes b/n populations
- p+q=1....what do p and q stand for?
-
Different gene alleles.
p=A
q=a - Homozygous
- having a pair of identical alleles for a gene locus
- Heterozygous
- having two different alles at a gene locus
- Dominant
- fully expressed in the phenotype
- recessive
- not expressed in the phenotype
- codominant
- different alleles both affect the phenotype in different ways
- A geneticist would consider evolution as
- a change in the gentic composition of a population's allele frequency over time
- gene pool
- all the alleles that exist in a population for a particular gene or sets of genes
- Hardy Weinberg Principle
- Alle frequencies remain constant in succeeding generations as long as no evolutionary change occurs
- Hardy Weinberg Equilibrium
- allele frequencies do not change between generations.
- Hardy Weinberg Assumptions
-
1)There is no selection
2)There is no mutation
3)There is no migration
4)Population is large
5)Mating is random - Mendel's Law of segregation
- hereditary units are passed on unaltered between generations
- Locus
- site on a chromosome
- Two types of Variability
- Discrete and continuous
- Discrete variation
- 2 or several distinct types
- Continuous variation
- many intermediate phenotypes between extremes
- Sources of variability
-
Genetic Recombination
Mutations - Genetic Recombination
- formation in the offspring of gene combinations not found in either parents
- Mutation
- A change in the base sequence of DNA
- Key point of Mutation
- New alleles originate only by mutation
- Nucleotide bases
-
Adenine A
Guanine G
Thymine T
Cytosine C - Codon
- set of 3 nucleotide bases, coding for a particular amino acid (via tRNA)
- Point Mutations
- Substitution of single base pair
- Transition Mutation
-
A switch between the purines
purine-->purine (A-->G) - Transversion Mutation
- less common, type of mutation, switch between purine and pynmidine
-
True or False:
Mutation in directed by the environment - False. environmental factors can indude mutations but these are not necessarily adaptive
- Influences on mutation rates
-
radiation
chemical mutagens
poor nutrition - Fossils
- any trace left by an organism that lived in the past
- Paleontology
- the study of fossils
- Fossil Categories
-
Compression and impression
Permineralized
Casts and Molds
Unaltered remains (rare) - Types of Bias in fossil record
-
Geographic
Taxonomic
Temporal - Examples of Geographic fossil record
-
Aquatic habitats favored
Lowland plains - Taxonomic
-
most animal phyla lack hard parts, bone or shell
phyla inhibiting marine or swamp environments favored - Temporal
-
old sedimentary rocks are rare
metamorphosis of rocks destroys fossils - Compression and impression fossils
-
burial prior to decomposition
2-dimensional - Permineralized fossils
- minerals precipitate into cells
- Casts and molds
- remains decay/dissolve away
- Casts
- new material fills space
- Molds
- space left unfilled
- Unaltered remains (rare)
-
decomposition is incomplete
Anaerobic conditions - Two types of reconstructive dating techniques
-
Relative dating
Absolute dating - Relative dating
- strata nearer the surface are younger than deeper strata
- Absolute dating
-
some elements exist naturally
isotopes are incorporated into organisms in this "background ratio
Unstable isotopes decay at a fixed rate. - Three parts of Geologic Time scale
-
Cenzoic
Mesozoic
Paleozoic - meaning of phanerozoic
- physical life
- types of animals in Paleozoic level
- Aquatic animals are in ________ level
- types of animals in the mesozoic level
- reptiles
- types of animals in the cenozoic level
- Birds and mammals are in the ________level
- What causes transitions in fossil record?
- diversification of certain taxonomic groups
- what factors allow for transitions in fossil records?
-
Environmental change
Extinctions - gene flow
- movement of alleles between populations
- genetic drift
- random changes in allele frequency from one generation to the next
- taxonomy
- science of identifying and naming taxa
- father of taxonomy
- carl linnaeus
- morphology
- physical structure of an organism
- Lumpers
- group animals into species
- Spliters
- split species apart
- Morphological species concept
-
species based on morphology
similar organisms likely to be related
"type specimen" = ideal of species - Convergent evolution
- similarity between unrelated species that result from independent evolutionary change in response to similar environmental conditions
- Placental mammals
- baby born when developed
- Australian marsupials
- baby develops in the pouch
- Biological Species concept
- species are potentially interbreeding natural populations that are reproductively isolated from other such groups.
- Why evolutionary force is prevented between species
- Gene flow
- barriers to gene flow
-
Prezygotic barriers
Postzygotic barriers - definition: Prezygotic barriers
- reduce likelyhood of hybrid zygotes
- definition: postzygotic barriers
- reduce fitness of hybrid zygotes
- Examples of Prezygotic barriers
-
Habitat
Temporal
Behavioral
Mechanical
Gametic - Habitat (prezygotic barrier)
- when two species live in two different places preventing them to breed
- Temporal (prezygotic barrier)
- related insects separated/isolated because of season
- behavioral (prezygotic barrier)
- most important barrier w/animals. courtship and mate choice
- mechanical (prezygotic barriers)
- different species cannot mate and transfer sperm
- gametic (prezygotic barrier)
- important for externally fertilized animals. sperm and egg are not compatible
- isolating mechanisms
- prevent gene flow and prevent mating or union of sperm and egg
- Postzygotic barriers
-
hybrid inviability
hybrid sterility
hybrid breakdown - hybric inviability
- when zygote seperates and dies at gastula stage
- hybrid sterility
- often one sex is sterile
- hybrid breakdown
- 1st generation is sterile
- Phylogenetic Species Concept
-
based on evolutionary history
any cluster that includes a common ancestor and all decendants - Speciation
- evolution of reproductive isolation within an ancestral species
- Cladogenesis
- Another name for speciation
- Modes of Speciation
-
Allopatric
Sympatric - Allopatric
- Species get seperated, they adapt to new situation and environment and they come together again....but according to BSC they cannot breed
- Sympatric speciation
- seperation by ecological factors...ex:living in different trees/flowers
- animal behavior
- what an animal does and how it does it
- 2 components of behavior and examples
-
Genetic (nature)
* Innate behavior
Environmental (nurture)
* Learning - definition: innate behavior
-
developmentally fixed
e.g begging in nestling birds - definition: learning
- behavior modified by experience
- Is animal behavior Nature or Nurture?
- Animal behavior is both nature and nurture
- fixed action pattern
- sequence of behavioral acts that is unchangeable
- Explaination of an organism's success in life
- some organisms do a little better than others it's not a live or die situation
- Company comparison of living
- organisms are like a company...everything they do has costs and benefits
- "company profits"
- # of offspring can be considered to this in the company organism analogy
- company balance sheet
- fitness can be compared to this in the organism company analogy
- Types of interactions
-
Cooperation
Selfish
Altruism
Spite - def: coorperation
- actor benefits & recipient benefits
- def: selfish
- actor benefits & recipient is harmed
- def: spite
- actor is harmed & recipient is harmed
- def: Altruism
- actor is harmed & recipient is benefited
- def: social interactions
- interactions between individuals of the same species
- Hypothesis for evolution of altruism
-
Individual advantage
Kin selection
Reciprocal altruism - def: and founder of Kin selection
-
average proportion of genes of individual A that are present also in individaul B.
W.D Hamilton 1964 - Kin selection
- natural selection based on indirect fitness gains
- 2 components of fitness
- Direct and Indirect fitness
- def: direct fitness
- personal reproduction
- def: indirect fitness
- additional reproduction by relatives made possible by an individual's actions