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AP 22-25
Natural Selection - Phenylogy & Systematics
72
Biology
11th Grade
02/27/2008

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Term
Why is Darwin so celebrated as opposed to ____________ who sent him his own theory on natural selection?
Definition
Because he was the first with evidence.

Alfred Russell Wallace sent him his essay on his theory of evolution.
Term
SPECIAL HISTORICAL FIGURES!
Definition
Linnaeus - the first with classification, for the greater glory of god.

Hutton - gradual geologic change with Lyell; the earth is older than 6,000 years

LaMarck - species can change - although he was wrong - he thought that acquired traits were hereditary

Cuvier - catastrophism - fossils and sedimentary rock; paleontology

Lyell - modern geology - gradual change with Hutton

Darwin (duh)
Mendel (Duh)

Wallace - sent darwin his theory of evolution - darwin published the next year
Term
Gradualism
Definition
that change takes place in long, continuous processes
Term
HMS Beagle
Definition
the ship that darwin sailed on - galapagos island - finches - through his data he began to develop theory of evolution
Term
GALAPAGOS FINCHES
Definition
the Cactus Eater - long, sharp beak for getting juice from cacti
the Seed Eater - short, solid beak for cracking seeds
the insect eater - long, narrow beak for trapping insects
Term
Descent with modification
Definition
survival of the fittest
the genes that suit the environment best will be selected for and will be more common in the gene pool because the offspring with them will survive
Term
the observations of ernst mayr
Definition
1. populations would increase exponentially if all offspring reproduced successfully
2. populations do not grow exponentially - they are stable in size (seasonal flux n/a)
3. resources are limited in supporting a population
4. members of a population vary in characteristics
5. variation is heritable
Term
the inferences of ernst mayr
Definition
1. the limited resources cause a struggle to survive - hence, survival of the fittest, only a fraction survive
2. part of survival is inherited traits
3. the unequal ability to adapt and survive --> a gradually changing population where the most common traits are the most favorable
Term
a population
Definition
a group of organisms that are capable of interbreeding and producing fertile offspring
Term
artificial selection
Definition
humans cloning plants/organisms that they want - broccoli, cauliflower, cabbage
Term
NATURAL SELECTION
the guppy example
Definition
killifish like guppies small, therefore, the guppies are larger at sexual maturity, therefore they have a better chance of making offspring
pike-chiclids like large guppies, therefore the guppies are small at sexual maturity, therefore they will be more likely to reproduce successfully

move sexually small guppies into pond will killifish - 11 years later, the guppies grew to be larger at sexual maturity
they adapted!
Term
NATURAL SELECTION
the HIV - Drugs example
Definition
medications select for viruses that are resistant to the drugs, because the rest of the virus population will not have a certain mutation, therefore it will die from the drugs
this poses a threat to our society
Term
homology
Definition
similarity resulting from common ancestry
ex: humans, cats, whales, and bats all have similar arm structures - the humerus to the metacarpals
Term
comparative embryology
Definition
seeing the similarities between different organisms in their stage of being a fetus - addtional homologies not seen in adults
ex: post-anal tail in humans and chickens, also the pharyngeal pouches
Term
vestigial organs
Definition
organs that are remnants of structures used by an ancestor but are not used today
ex: the appendix, the tailbone
Term
Analagous vs. homologous
Definition
Term
microevolution
Definition
change in genetic make-up from generation to generation
Term
Fixed Gene
Definition
in a gene pool, if there is only one gene available for a particular locus, it is called a fixed gene
Term
Hardy Weinberg Equilibrium equation
Definition
p^2+2pq+q^2 = 1
p+q=1
p= number of dominant alleles
q= number of recessive alleles
p^2 = Homozygous dominant
2pq = heterozygotes
q^2 = homozygous recessive
Term
Hardy-Weinberg Theorem
What is needed for hardy-weinberg to work
Definition
- that from generation to generation, the allele frequencies will not change
1) no natural selection
2) no gene flow
3) no MUTATIONS
4) large population
5) random mating

hardy weinberg does not work perfectly because populations do change
Term
we can use the hardy-weinberg theorem to...
Definition
predict / estimate the number of carriers for recessive diseases
Term
point mutations
Definition
change in one base of a gene
can be significat to phenotype
is usually harmless, but my have an adaptive impact
Term
chromosomal mutations that affect many loci...
Definition
almost always harmful
but translocations can be beneficial
Term
gene duplication
Definition
duplicates chromosome segments
ex: olfactory receptors in mice and humans
Term
mutation rates
Definition
are faster the quicker the organisms reproduce
Term
sexual recombination
Definition
is way better than mutations and allows for adaptation
Term
Genetic Drift
Definition
when only certain members of a population are able to sexually reproduce
Bottleneck effect - a sudden change in environment that leaves a fraction surviving --> the gene pool will not be reflective of the original population

the founder effect - a population is separated - a few individuals are isolated --> will affect the frequences, especially homozygous recessive behavior (due to carriers and interbreeding)
Term
macroevolution
Definition
the big picture - many different microevolutionary instances
Term
Gene Flow
Definition
the emigration and immigration of genes into the pool - causing the population to gain or lose alleles
Term
genetic variation
variation within a population - characters
Definition
occurs in individuals of all species

-disrcrete characters = an either-or basis (short or tall); no spectrum
-quantitative characters - vary along a continuum / spectrum
Term
Polymorphism
Definition
the quality or character of occuring in different forms

phenotypic polymorphism - two or more distinct morphs for a character that are represented in a high enough frequency to be readily noticeable

genetic polymorphism - heritable components of characters that occur along a spectrum
Term
geographic variation
Definition
differences in gene pools of separate populations of different species

occuring as a cline - graded change in a trait along a geographic axis
Term
Genetic Fitness and Relative Fitness
Definition
the more kids you have, the more genes you supply to the gene pool

relative fitness - the contribution of a genotype to the next generation compared to the other possible genotypes for a particular locus
Term
Selection models
Definition
Directional - favors one extreme of a bell curve - bell curve moves towards one end

disruptive - goes towards both extremes from a bell curve

stabilizing - goes toward the middle of the spectrum from the extremes
Term
Diploidy
Definition
having two alleles for each gene - allows for recessive genes to survive
Term
Balancing Selection
Definition
when natural selection maintains two or more phenotypic forms in a population ==> BALANCED POLYMORPHISM
Term
heterozygote advantage
Definition
greater fitness than homozygotes (sickle-cell anemia example)
Term
frequency-dependent selection
Definition
the fitness of any morph declines if it is too common in a population - predator shifts its feeding habits
Term
Sexual Selection
Definition
natural selection in mating

2 kinds

Intrasexual - members of one sex fighting eachother for one of the other (humans, gorrillas)
Intersexual - one sex (females) being choosy in their mate, and usually go for the flashiest appearance (i.e. birds)
Term
Asexual vs. Sexual Reproduction - benefits and handicaps
Definition
Asexual - more offspring each generation, but no variation
sexual - variation in every new generation
Term
Speciation
Definition
the origin of new species
Term
Two evolutionary patterns
Definition
Anagenesis - gradual change where the original species is completely lost and the new species replaces its ancestor
Cladogenesis - the brancing where the original species is preserved in its descendants
Term
Definition of a SPECIES
Definition
a population or a group of populations that are able to interbreed and produce fertile, viable offspring
Term
Prezygotic barrier
Definition

reproductive isolation which impedes members of a species from interbreeding - it prevents the actual mating of two organisms

1) Habitat isolation (living in two different places)

2) Temporal isolation - day v. night

3) behavioral isolation - mating rituals

4) mechanical isolation - live in different places

5) Gametic isolation - incompatability at the molecular level

Term
Postzygotic Barriers
Definition
prevent hybrid zygot from developing into fetile adult
1) Reducing hybrid viability - doesn't develop
2) reduce hybrid fertility - can't reproduce
3) hybrid breakdown - falls apart because it's so unstable
Term
Morphological species
Definition
characterizes a species by appearance and structure
Term
ecological niche
Definition
a way of life in a certain environment
(habitat = where they live)
Term
phylogenetic species concept
Definition
defines species in terms of their ancestors
Term
Allopatric Speciation
Definition
when a population is physically split and evolves in different environments, therefore selecting for different genes
Term
sympatric speciation
Definition
when a population is not physically split, but evolves differently due to, at some point, enough genetic difference to hinder interbreeding.
can cause the the appearance of new ecological niches
Term
Adaptive Radiation
Definition
evolution upon introduction to new environmental opportunities - causes adaptation
example: the hawaiian archipelago
Term
Punctuated Equilibrium
Definition
new species bud from parent then changes little during its existence - a tree
Term
Polyploidy
Definition
caused by nondisjunction; extra sets of chromosomes - prevalent in plant evolution
and AUTOpolyploid - chromosomes from the same species
ALLOpolyploid - chromosomes of different species
Term
novel biological structures
Definition
complex structures like the eye - evolved but had the same function throughout its ancestry
Term
Heterochrony
Definition
evolutionary change in the rate or timing of development
ex: salamander feet - ground v. tree dwelling
Term
allometric growth
Definition
tracks / controls proportioning
ex: shapes of human and chimp skulls
Term
Paedomorphosis
Definition
rate of reproductive development accelerates compared to somatic development ==>
sexually mature species retains structures from a juvenile state
Term
Homeotic genes
Definition
spatial and temperal

determine locations of body structures

ex: Hox gene provides positional information for development of fins and limbs
Term
Exaptations
Definition
structures that evolve in one context, but are used in another.

ex: a bird's lightweight bones predate flight, perhaps wings used for thermal regulation
Term
species selection model
Definition
and individual as a species
speciation = birth
Extinction = death
new species = offspring
Term
systematics
Definition
the tree of life

uses morphological, biochemical, and molecular comparisons to infer evolutionary relationships
Term
sedimentary rocks
Definition
rich source of fossils in deposited layers called strata - most common
Term
what's so awesome about fossils?
Definition
they show ancestral characteristics that have been lost over time
Term
Convergent Evolution
Definition
produces similar / ANALAGOUS structures in species that have different evolutionary lineages due to similar environments

these analagous structures are called homoplasies
Term
Computer programs used for systematics
Definition
compare DNA sequences from different organisms
Term
Taxonomy and Binomial Nomenclature
Definition
the ordered division of species into categories based on similarities and differences

the binomial nomenclature was developed by Linnaeus (although he sucked at organizing because it was all morphological), using latin, names the genus and the species

Dear King Phillip Came Over For Good Soup
Domain Kingdom Phylum Class Order Family Genus Species
Term
Phylogeny
Definition
the evolutionary history of a species
Term
a Clade
Definition
a certain branch of the phylogenic tree

MONOphyletic - an ancestor and all its descendants
PARAphyletic - an ancestor and some of its descendents
Term
a primitive character
Definition
a homologous structure that predates the branching of a particular clade and is shared beyond the taxon
Term
Parsimonious Trees
Definition
the fewest branches; recquires the least amount of evolutionary events for shared derived characters

during CONVERGENT evolution, is it not always the most parsimonious tree that fits the best hypothesis
ex: four-chambered heart in birds and beavers
Term
Molecular clocks
Definition
a certain rate of mutation / evolution, which stays the same.
involved in neutral theory, which states that fitness has nothing to do with darwinian selection
clock does not run this smoothly
HIV example - comparison of HIV samples from throughout the epidemic - descendant from HIV that infected primates
Term
Three Great Clades
Definition
Eukarya, Bacteria, Archaea
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