Midterm 1 Flashcards
Who came up with the idea of Biodiversity?
E. O. Wilson
What did EO. Wilson say about biodiversity?
The totality of inherited variation in all organisms of a selected area
Why is evolution important?
B/c nothing makes sense in biology except in the light of evolution
What are the 4 things evolution allows us to understand?
1- diseases
2- explains diversity of life on earth
3- agriculture = plant/animal breeding and origin of crops
4- managing wildlife
What is biology defined as?
The study of living organisms and life processes
What are the. 4 major concepts of biology?
1- hierarchy of biological organization
2- emergent properties of systems
3- diversity of life
4- evolution
Explain Hierarchy of biological organization as a major concept of biology
Life can be organized into structural levels.
At each successive level additional emergent properties appear
What are the 8 different levels in the hierarchy of biological organization?
1- Atomic level 2- Molecular level 3- Organelle level 4- Cellular level 5- Tissue level 6- Organ level 7- Organ system level 8- Organism level
Instead of the 8 levels of hierarchy of biological organization, what are the 14 structures?
1- atoms 2- complex biological molecules 3- sub-cellular organisms 4- cells = basis units of structure and functions (similar cells are organized) 5- tissues, 6- organs 7- organ systems 8- individuals = complex organisms 9- group, 10- population 11- community, 12- ecosystem 13- biomes, 14- biosphere
What are the 6 levels of organizations in biodiversity? Where does evolution happen?
1- Species 2- subspecies 3- population (evolution happens here) 4- individuals or phenotype 5- genotype 6- DNA
Explain Emergent properties of systems as a major concept of biology
Properties that arise as a result of interactions between component parts
Give 2 examples of emergent properties of systems as a major concept of biology
1- Hydrogen bonding between water molecules
2- spontaneous folding of polypeptide chains
Explain Diversity of life as a major concept of biology
There is 1.2 million species of living organism that have been describes and classified
BUT total # not yet described could be 9-11 million
What is classification as a part of diversity of life on earth?
Categorized diverse items into small # of groups
What is taxonomy?
Branch of biology that names and classifies species into hierarchical order
What is the modern taxonomy system called? When was it made? By who?
Binomial nomenclature - 1735 by Carolus Linnaeus
What are the 7 levels of Binomial nomenclature?
1- kingdom 2- phylums 3- class 4- order 5- family 6- genus 7- species
How do we write the names of the organisms in binomial nomenclature?
Genus then Species
Both italicizes but only genus Capitalized
How has the binomial nomenclature changed since its invention?
Used to be only 5 kingdoms - now 6-8 added
Added 8th layer = Domain - higher than kingdom
What are the 3 Domain levels?
Bacteria
Archaea
Eukarya
What 2 things can be said about the 3 domains?
1- bacteria and archaea are prokaryotes
2- archaea more closely related to eukarya than bacteria
What 4 kingdoms of the domain Eukarya do we need to know?
1- animalia
2- Fungi
3- plantae
4- Protista
What is the underlying diversity of life on a microscopic level?
Sticking unity
What is the universal genetic language?
DNA unites
In eukaryotes unity is evident in?
Many details of cell structures
What is evolution?
Combination of unity and diversity of life
Explain Evolution as a major concept of biology
The core theme of biology = how life evolves
Explain the tree of life (3)
- Each species is one twig
- Species that are very similar = share common ancestor = 2 twigs from recent branching point
- similarities in cellular structure (cilia) = common ancestor for all eukaryotes
How is all life connected?
Through evolution
What did Charles Darwin come up with and in what year?
The origin of species - in 1859
What was darwin’s 2 main ideas in the origin of species?
1- contemporary species arose from a secession of ancestors through “descent with modification” = evolution
2- mechanism of evolution is natural selection
Explain Darwin’s descent with modification
Similarities between species grouped in same taxonomic category
What is an example of descent with modification?
Forearms in humans, cats, whales and bats = share same skeletal elements but different functions b/c they diverged from ancestral tetrapod forelimbs = they have homologous structures
What was Darwin’s first observation about NS?
Individuals in a pop of any species vary in many heritable traits
What was Darwin’s second observation about NS?
Any pop can potential produce far more offspring then the environment can support = struggle for existence among variant member of pop
What was Darwin’s conclusion about his two observations fro NS?
Those individuals with traits best suited to the local environment will generally leave more surviving and fertile offspring
What can NS do over long periods of time?
Produce new species from ancestral species
If a pop is fragmented into isolated groups what will happened to them?
Began as one species diverse is into many - each changing to adapt to its different environmental problems
What is adaptive radiation?
Flinches of Galápagos Islands diversified after an initial colonization from the mainland to exploit different food sources on different islands
What does descent with modification account for?
Both the unity and diversity of life
Where is descent with modification generally seen?
Feature shared by 2 species due to their descent from a common ancestor
How can NS have an impact of descent with modification?
Modifies ancestral equipment in different environments
Flow chart showing Darwin and NS with 4 observations and 3 deductions - What is the first observation?
From plant and animal breeders - variation among individuals in pops exists and is an inherent property of pop
Flow chart showing Darwin and NS with 4 observations and 3 deductions - What is the second observation?
From plant and animals breeders - variation is heritable (=genetics)
Flow chart showing Darwin and NS with 4 observations and 3 deductions - What is the third observation?
From Malthus - pop can only grow a certain size (carrying capacity) in a particular environment and then reach a steady state
Flow chart showing Darwin and NS with 4 observations and 3 deductions - What is the fourth observation?
Darwin - organisms produces large # of offspring each generation and tend to have a geometrical rate of increase
Flow chart showing Darwin and NS with 4 observations and 3 deductions - What is the first deduction?
Darwin - in. Each generation many more offspring are produced than can possibility survive
Flow chart showing Darwin and NS with 4 observations and 3 deductions - What is the second deduction?
Darwin - there is a “struggle for existence” among members of each pop
Flow chart showing Darwin and NS with 4 observations and 3 deductions - What is the third deduction?
Darwin - individuals possessing variations that enable them to compete better than others in same pop in the “struggle for existence” will leave more offsprings = favorable traits will increase freq in pop over time as long as environment remains same = NS
Flow chart showing Darwin and NS with 4 observations and 3 deductions - Which observation supports which deduction?
Ob #1 (Inherent) - Ded #3 (Variation)
Ob #2 (genetics) - Ded #3 (variation)
Ob #3 (capacity) - Ded #1 (more offspring)
Ob #4 (Geometrical) - Ded #1 (more offspring)
What is geological time?
Fossil evidence of life up to 3.5 BYA or BYBP
How long has fossil evidence shown homo spines have been in extended for?
500,000 yrs
What are the 3 different fauna of time?
1- Cambrian
2- Paleozoic
3- Modern
What are the 5 mass extinctions as a feature of life on earth over geological time?
1- end of Ordovician 2- end of Devonian 3- end of Permain 4- end of Triassic 5- end of Cretaceous
What is the second feature of life on earth over geological time?
Turn over of species diversity
What is the third feature of life on earth over geological time?
Origin of a group doesn’t necessarily coincide with its radiation (proliferation (rapid increase in numbers) or diversification)
What is an example of the third feature of life on earth over geological time?
Mammals = originated early but once last ice age was over were allowed to expand and turn into many species
What are the 5 evidences of evolution?
1- direct observation of evolution in action
2- fossil records
3- anatomy and embryology
4- biogeography = pattern, processes and distribution
5- molecular biology = DNA and RNA
What did Darwin believe to be impossible about evolution?
That it could happen within a lifetime
Give 2 examples of evolution with a lifetime
1- antibiotic resistant bacterias
2- herbicide resistant plants
What is 1 of 4 direct observations of evolution?
1- E. Coli grown in glucose. Limited “broth” contained citrate. E. Coli cannot use critate for food but after serval years one group did
What is 2 of 4 direct observations of evolution?
Elephants hunted for tusks = some groups have become tusk less
What is 3 of 4 direct observations of evolution?
Darwin’s flinches on Daphne Major island = beak grew shorter and smaller for foods
What is 4 of 4 direct observations of evolution?
HIV evolution in 9 different people = HIV has variations
Define evolution
Descent with modification
What is genotype?
The underlying genetic makeup of an organism or of a phenotype
What is phenotype?
An observed trait expressed by an organism
What is a gene?
A physical and functional unit of DNA - could be a sequence of DNA that codes a protein
What is the Locus?
A position on a xsome - physical know position of a gene on a xsome
What is an allele?
Variations that arise by mutation an exist at that some locus on homologous xsome
What is a species?
A group of potentially interbreeding individuals that is reproductively isolated from other groups
What is a subspecies?
A recognized (named) tax on below the species level
What is a population?
A group of individuals with roughly equivalent probability of mating with each other
Define evolution
Descent with modification
What is genotype?
The underlying genetic makeup of an organism or of a phenotype
What is phenotype?
An observed trait expressed by an organism
What is a gene?
A physical and functional unit of DNA - could be a sequence of DNA that codes a protein
What is the Locus?
A position on a xsome - physical know position of a gene on a xsome
What is an allele?
Variations that arise by mutation an exist at that some locus on homologous xsome
What is a species?
A group of potentially interbreeding individuals that is reproductively isolated from other groups
What is a subspecies?
A recognized (named) tax on below the species level
What is a population?
A group of individuals with roughly equivalent probability of mating with each other
What can variation in nature be?
Continuous or discontinuous
What is genetic variation within individuals?
Variation in a DNA sequence identifying a single nucleotide polymorphism (SNP)
What is population genetics?
The study of the change in allele freq in a pop over time
What are the 3 factors of population genetics?
1- calculation genotype and allele freq
2- heterozygosity
3- Hardy-Weinberge equilibrium
In gene counting what are the 3 genotypes?
AA
Aa
aa
In gene counting what are the 3 numbers associated with genotypes?
AA = A Aa = B aa = C
What does the genotype number equal?
A + B + C = T (total)
How do we find frequency of the 3 genotypes? (Genotype Frequencies)
AA = D = A/T Aa = H = B/T aa = R = C/T
What do the genotype frequencies equal?
D + H + R = 1
What is the allele frequency equation for A? From freq and from number
P = D + 1/2 H
(A + 1/2B)/T
What is the allele frequency equation for a? From freq and from number
q = 1/2H + R
(1/2B + C)/T
What is Hardy-Weinberg equilibrium?
The first theory of population genetics
What are the 4 factors of Hardy-Weinberg equilibrium?
1- diploid organism = 3 genotypes = AA, Aa, aa
2- 2 allele at genetic locus = A and a
3- expect to be random mating
4- use rules of maxilla an segregation
What are the expected frequencies of genotypes after one generation for HW?
AA = p^2 Aa = 2pq aa = q^2
What are the expected frequencies of genotypes for HW equal?
p^2 + 2pq + q^2 = 1
What is binomial distribution?
After one generation of random mating = HW genotype freqs. will only change if a selection occurs (this will be starting point)
In recessive vs dominant HW equations, what does the recessive observed genotype freq equal?
(aa) = q^2 or R = C/T
In recessive vs dominant HW equations, what does the recessive allele freq equal?
(a) = root(q^2) or root(R) = root(C/T)
What causes variation?
Environment
What is the definition of variation?
An individual’s phenotype represents the combined effects of genotype and environment
For variation what is the phenotype equation?
P = Genotype + Environment + (genotype X environment) P= G + E + (G x E)
What is the G, E and GxE in the phenotype equation?
G = genetic effect E = environmental effect GxE = genetic effects whose expression depends on environment or environmental effects which only occur for certain genotypes
What is phenotype plasticity?
Role of environment = environmental sensitive production of alternative phenotypes by a given phenotype
What is heritability?
Fraction of the total phenotypic variation in a pop that is caused by genetic different among individuals
How do we measure heritability?
Must know amount of phenotypic and genetic variation in pop
What are the 3 factors we use to measure heritability?
Vp = phenotypic variation Vg = genetic variation Ve = environmental variation
What does phenotypic variation equal in heritability?
Vp = Vg + Ve = genetic variation + environmental variation
What is the equation for heritability?
Heritability = h^2 = Vg/Vp = genetic variation / phenotypic variation
What is inheritance?
Transmission of traits from one generation to the next
Explain what heritability is and isn’t
It is a property of a pop at any given time (may have different allele freq and environmental differences)
It is not an inherent property of a trait
How do we graphically determine heritability?
y-axis = mean offsprings vs x-axis = mean parent
Slope = h^2 = has to be between 0 or 1.
If equal 0 then there is no relation
What did Darwin (like other scientists) assume before his travels?
Assumes species were specially created by God and were unchanging
What are Darwin’s first 4 chapters in his “the origin of species” book - 1859?
Ch 1 - domestic variation
Ch 2 - natural variation
Ch 3 - struggle for life
Ch 4 - natural selection
What was Darwin’s chapter 4 “natural selection” based on?
3 facts
What was the first fact Darwin’s chapter 4 “NS” based on?
Phenotype variation amount individuals
What was the second fact Darwin’s chapter 4 “NS” based on?
Particular phenotypes survive in the struggle for life
What was the third fact Darwin’s chapter 4 “NS” based on?
Phenotypic variation is heritable
What does the 3 facts that Darwin’s chapter 4 “NS” make up?
Fact 1 + 2+ 3 = evolution by NS
What are the 3 ways in which we see evolution by NS work?
1- stabilizing selection
2- directional selection
3- diversifying selection
Explain stabilizing selection as a type of evolution by NS
In a stabilizing selection an average phenotype is favored = around the “mean” average
Describe the statistic graph of a stabilizing selection
Original pop = bell curve
Pop after NS = taller, thinner bell curve in the middle of original pop
Explain directional selection as a type of evolution by NS
Directional selection is a change in the environment which shifts the spectrum of phenotypes observed
Describe the statistic graph of a directional selection
Original pop = normal bell curve
Pop after NS = normal bell curve that has been shifted or moved to start more to the right or from the middle of original
Explain diversifying selection as a type of evolution by NS
Diversifying selection is when 2 or more extreme phenotypes are selected for, while the average phenotype is selected against
Describe the statistic graph of a diversifying selection
Original pop = normal bell curve
Pop after NS = M shaped curve where the 2 highest peaks are either side of the original curve and the lowest peak is at the dips in the middle of the original curve
How do we determine variability of allele freqs?
Viability = w (substrate 1 or 2 depending on genotype) x allele genotype freq (p^2 or 2pq or q^2)
What is the mean survival of pop?
= w..p^2 + w..2pq + w..q^2
For natural selection freqs what is s and h?
S = selection coefficient H = dominance coefficient
What does variability freq (w) equal?
W = 1 - s or 1 - selective coefficient
Once you have the variability selection allele freq how do you get back to genotype allele freq?
w..p^2 / mean w = p^2
Mean w = w..p^2 + w..2pq + w..q^2
What is the relation fitness equations for the genotypes AA, Aa and aa?
AA = 1 Aa = 1 + (H X S) aa = 1 + S
What happen if there is no genetic variation?
No change will occur
For response to selection what are the 3 factors?
R = response to selection S = selection differential H^2 = heritability where it's between 0 and 1
What is the response to selection equation?
R = h^2 x S
What does a higher value for R is response to selection mean?
Higher R = higher response to selection = faster evolutionary change
If NS causes adaptation what 5 processes cause pops to evolve?
1 - NS 2 - genetic drift 3 - Gene flow 4 - mutation 5 - non-random mating (sexual selection)
Which one is or isn’t by chance between NS and GD (genetic drift)?
NS = not by chance GD = all on chance = cannot be predicted
What is genetic drift?
A change in the gene pool of a pop due to chance
What is important to remember about GD and chance?
Predominant in small pops = chance events may lead to loss of genetic diversity
Why are smaller pop effected more by GD?
Experience greater random effects than large pops
What is GD about other than chance?
Pop size
What is the first insight to GD?
Causes an average loss of genetic variation within a pop
How does GD cause a loss in genetic variation?
Alleles are lost = homozygosity increase and heterozygosity decrease
If alleles are lost due to GD changing genetic variation, what will happen?
Increase of probability of fixation of any given allele is equal to its freq
What is the equation for probability of fixation?
E.g. A or a = p or q /2n
Where n = pop size and 2n is total # of all alleles in a diploid pop
Explain what fixation is
Is when freq = 1 or 0. 1 to be fixed in a pop and 0 to be completely lost from pop. Which means one allele (A or a) is fixed and one is eliminated
What is the second insight to GD?
Causes on average genetic divergence between pops
How does GD cause genetic divergence between pops?
Unlikely that random alleles freq changes in different pops will have the same result = no 2 pops will have the same GD
What is gene flow?
Move to of alleles between pops b/c individuals move around
What is important to remember about gene flow?
Can alter allele freq in a pop
Why can gene flow alter allele freq in a pop? (2)
Due to movement of individuals and movement of gametes (e.g pollen and spores)
What is the rate of gene flow?
of individuals moving into a pop per year = can be high or low
What is the difference between mainland and island gene flow?
Mainland = selecting favoring regular pattern = diff between Dom and rec Island = selecting favoring reduced pattern = more equal between Dom and rec
What is important to remember about gene flow?
Can alter allele freq in a pop
Why can gene flow alter allele freq in a pop? (2)
Due to movement of individuals and movement of gametes (e.g pollen and spores)
What is the rate of gene flow?
of individuals moving into a pop per year = can be high or low
What is the difference between mainland and island gene flow?
Mainland = selecting favoring regular pattern = diff between Dom and rec Island = selecting favoring reduced pattern = more equal between Dom and rec
What does biological species concept emphasize on?
Reproduction isolation
What do prezygotic and postzygotic barriers do?
Isolate the gene pools of biological species
What is speciation?
The formation of 2 species from one original species - always have a common ancestor
What is adaptive radiation?
A sequence of multiple speciation events from an original ancestor (during a relatively short period of time)
What helps with adaptive radiation?
Less competition
What do islands have due to adaptive radiation?
Endemic species (not seen anywhere else) - this results from NS but still originates from common ancestor
What is macro-evolution?
Origin of new taxonomic groups due to micro = change in allele freq
What does species mean in Latin?
Kind or appearance
Who introduce biological species concept?
Mayr - 1942
What was Mayr’s idea behind biological species concept?
A species is a pop or group of pop whose members can interbreed with each other in nature to produce viable, fertile offspring and cannot do this with members of other species
What is a species?
Groups of interbreeding natural pops that are reproductively isolated from other groups
What are the issues dealing with species as the biological species concept? (3)
Reproductively isolated = zero gene flow = no hybridize (gene flow between species)
Doesn’t make sense for asexual species
Can’t apply when only dealing with fossils
What are the 2 types of isolating/reproductive barriers (isolate gene pools) and when do these occur?
1- prezygotic = before mating/ before making zygote
2- postzygotic = after mating
Where does the reproductive barriers happen?
Symmpatrick = same place and not asympatrick = diff areas
What is hybridization?
2 different species produce viable offspring
What are the 5 reproductive barriers for prezygotic?
1- habitat isolation 2- behavioral isolation 3- temporal isolation 4- mechanical isolation 5- gametic isolation
Between which reproductively barriers would mating occur from prezygotic?
Between temporal isolation and mechanical isolation
Explain what is habitat isolation for prezygotic reproductive barrier
Symmpatrick but pops do not meet = same areas but different habitats
Explain what is behavioral isolation for prezygotic reproductive barrier
Little to no sexual attraction
Explain what is temporal isolation for prezygotic reproductive barrier
Mating/flowering occurs at different times or seasons
Explain what is mechanical isolation for prezygotic reproductive barrier
Difference in genitalia or gametes
Explain what is gametic isolation for prezygotic reproductive barrier
Egg and sperm don’t come together
What happens between prezygotic and postzygotic reproductive barriers?
Fertilization
What are the 3 reproductive barriers for postzygotic?
1- reduce hybrid viability
2- reduced hybrid fertility
3- hybrid breakdown
Explain what is reduced hybrid viability for postzygotic reproductive barrier
Zygote doesn’t develop int embryo
Explain what is reduced hybrid fertility for postzygotic reproductive barrier
Fail to produce functional gametes
E.g mule
Explain what is hybrid breakdown for postzygotic reproductive barrier
Offspring of hybrids decrease in viability and fertility
What are the 4 alternative species concepts than biological species concept?
1- ecological species concept
2- pluralistic species concept
3- morphological species concept
4- genealogical species concept
Explain ecological species concept as an alternative species concept
Species in terms of it’s ecological niche
What is an ecological niche?
Set of environmental resources that a species uses and it’s role in a biological community
Explain pluralistic species concept as an alternative species concept
May invoke reproductive isolation or adaptation to an ecological niche or use both in maintaining distinctive cohesive groups
Explain morphological species concept as an alternative species concept
The oldest and still most practical concept = defines a species by a unique set of structural feature
Explain genealogical species concept as an alternative species concept
Defines a species as a set of organisms with a unique genetic history - one tip of branching tree of life
What is hybridization? What can be said about there species?
Divergent species (share common ancestor millions of years ago) can mate and produce offspring They can hybridize
What can hybridization allow even against the odds?
Allows for hybrids to be and produce viable and fertile offspring
What is the modified biological species concept?
Species defines as distinguishable group of genotypes that remain distinct in the face of potential and actual hybridization and gene flow
What is the hybrid zone?
Area of overlap between species where hybridization occurs
What is the hybrid zone also known as?
Suture zone
What are the 3 changes in the hybrid zone?
1- reinforcement
2- fusion
3- stability
Explain reinforcement as a type of hybrid zone
Hybrids are less fit than purebred species. Species continue to diverge until no hybridization
Explain fusion as a type of hybrid zone
Reproductive barriers weaken until 2 species become one
Explain stability as a type of hybrid zone
Fit hybrids continue to be produced
