Allopatric speciation can occur after which of the following conditions?
dispersal
vicariance
Which of the following isolating mechanisms fits the criteria of being post-mating and prezygotic?
genetic barrier
Upland and southern chorus frogs exhibit greater differences in their call structure in areas of sympatry than in areas of allopatry. True or false
True
The name of a trait that helps define a monophyletic group
Synapomorphy
Female Rhagoletis select fruit for egg deposition primarily by
fruit scent
_____________ is the form of polyploidy where the gene sets are derived from two different species
allopolyploidy
A hexaploid plant has a chromosome count of 36. Which is the correct chromosome number for its diploid ancestor?
12
The African forest elephant was first recognized as a separate species using which species concept?
phylogenetic species concept
Cryptic species do not qualify as distinct species under the biological species concept.
False
Interactions observed
between Townsend's warbler and the hermit warbler-- two closely related and presumably recently evolved species --- provide a great example of reinforcement. t or f
False
Condition where more than two species arise from a single node in a phylogenetic tree is called a
polytomy
Another term that has the same meaning as monophyletic group.
clade
Term used to describe an assemblage of species whose most recent common ancestor is not part of the group.
polyphyletic group
A trunk crown Anolis from Hispaniola should be most closely related to a
A twig Anolis from Hispaniola
An adaptive radiation can be the result of
ecological opportunity
key innovation
Terminal branches in a phylogenetic tree are called
tips
The taxonomic category order falls just below the category class and just above the category family.
True
Modern whales and dolphins do not possess a pulley-like astragalus and therefore should not be included in the order Artiodactyla. true or false
False
_______ is the science of (and rules for) describing and classifying species and higher level phylogenetic groups
Taxonomy
The scientific name for the chimpanzee is Pan troglodytes; the second part of its binomial, troglodytes, is called the ____________.
specific epithet
What happens when populations become genetically isolated from one another?
When populations are genetically isolated, they evolve independently of one another!! Leads to speciation
Define speciation
the evolution of one or more species from an ancestral species
What is a species under the BSC?
actual interbreeding populations & potentially interbreeding populations that are reproductively isolated from other such groups (ability to
reproduce)
prezygotic isolation
prevents mating or zygot formation between species,
Habitat isolation
Temporal isolation-time
Behavioral isolation
Gametic barrier- fertilization doesn’t take place
Mechanical barrier- just doesan’t work
The mule provides an example of???
A hybrid, postzygotic isolation
What are some of the problems with the BSC?
Asexual organisms
Fossils
Hybridization
Morphospecies
Concept
What are its advantages? Disadvantages?
based on differences in shape, size, or other morphological features
advantage is asexual and fossils
disadvantage can’t account for cryptic species.
What are some of the problems with the Biological species concept?•
Asexual organisms•
Fossils•
Hybridization
Phylogenetic Species Concept
Monophyly
at least one derived trait that is unique to the group and occurs in all members of the group.
Synapomorphy-
shared derived trait between descendants of a common ancester
Why are synapomorphy and monophyly to the Phylogenetic Species Concept?
They are used to identify related species
Cryptic species: look identical morphologically, but are reproductively isolated.
Cryptic species.
Which species concept are they consistent with?
Inconsistent with?
Inconsistent with Morphospecies Concept. Correct with other concepts
Which species concept (s) ‘work ‘ with respect to fossils? To exclusively asexual organisms?
Morphospecies concept
The seaside sparrow subspecies peninsulae along Florida’s western coast appears to be in big trouble, i.e., going extinct. You are newly hired population geneticist in charge of its recovery. Would it be better to cross the few remaining individuals with Florida populations of the subspecies macgillvraii or junicola?
The junicola, because peninsulae and junicola are both sub species of the same monophyletic group
What do dispersal and vicariance share in common? How do they differ?
Vicariance- the splitting of a habitat
Dispersal-a section of a population disperses from the main population
Both "split" a population
Distinguish between allopatric
speciation vs. sympatric speciation. Provide examples of both.
Allopatric-the population has been parted due to geographic isolation (more common) (Shrimp)
Sympatric speciation-species variation has taken place without geographical isolation (due to ecological isolation) (apple and hawthorn maggots)
Which is more rare and why? Which of the two likely involves a ‘host shift’?
Sympatric speciation is rarer, it requires a
specific situation (example: the apple flys)
Polyploidy=
a genetic state involving more than two complete sets of chromosomes
Autopolyploidy-
chromosome sets from same species
Allopolyploidy
chromosome sets from two different species (via hybridization)
Complete set in genetics
haploid, there’s two sets of chromosomes per person so a complete set is the sperm or egg
Consider a pentaploid (5n) and an octoploid (8n) undergoing meiosis. Which is more likely to produce
functional gametes? Why?
I would think the octoploid, as the pentaploid would be an uneven number, leading to more complications and more likelihood of uneven numbered gametes
Name a major taxonomic group in which polyploidy has played a significant role in speciation.
Plants, they can undergo meiosis and produce gametes after many rounds of mitosis, some can self- fertilize, and hybridization is common
Reinforcement-
the natural selection of traits that prevent interbreeding between
recently diverged species
Reinforcement. In our example, what was the significance of size differences between the two millipede species in areas of sympatry?
Size differences make interbreeding less likely, reinforcing reproductive isolation and divergence
Sympatry-
species are close enough to permit breeding vs allopatry
What are hybrid zones?
A geographic area where interbreeding occurs and hybrid zones can form.
How do you determine character polarity?
Use the outgroup method
What is an ancestral character?
A characteristic that existed in an ancestor, the outgroup, 0 on the data matrix
What is a derived character?
One that is a modified form of the ancestral trait found in a descendant. 1 on data matrix
What is a synapomorphy, why are they important?
A shared derived trait, it’s what used to place organisms into monophyletic groups (clades)
Monophyletic-
A group that includes an ancestor and all its descendants
Paraphyletic-
Contains some but not all descendants
Polyphyletic-
Group whose most recent common ancestor is not
in the group.
Parsimony
The logical principle that the most likely explanation of a phenomenon is the most economical or simplest. Fewest branching
How does the principle of parsimony help you to select among possible trees?
With phylogenetic trees, it suggests that the one requiring the fewest evolutionary changes is most likely to be correct. As few branches as possible
What is an adaptive radiation?
Rapid evolutionary diversification producing many species that display a wide range of adaptive forms.
Many species radiating from a single node or lineage
Outline necessary steps for adaptive
radiation. Provide examples.
1 A single lineage 2 rapid speciation3 ecologically diverse
Tarweed to 30 species of silver
sword
Anolis to hundreds of species of
Anolis in Caribbean
Why do you think adaptive radiations occur more readily on islands?
Yes, any new “blank slate” environment
Compare ecological opportunity vs. morphological
innovation.
Ecological opportunity is when
there is a blank slate that a specie can expand on, morphological innovation or key innovation involves a trait that a specie has that almost allows it a blank slate, ie the different throat teeth in the fish species from class
What was the Cambrian explosion?
When did it occur?
Abrupt appearances of many species, all the major phylums.Origin and adaptive radiation of
animals
What explanations are offered for the Cambrian explosion?
Highest oxygen levels
Evolution of predation
(evolutionary pressure to produce mechanisms to either escape or protect themselves from predation ie increased mobility or hard
shell/exoskeleton)
Niche access and expansion
Hox gene duplication, anatomical
complexity
What is a mass extinction? How many are there in the
paleontological record?
Mass extinction- Extinction of a large number of elvolutionary change in a relativy short period of time
extraordinary sudden and temporary changes in environment
There have been five major extinctions
End-Cretaceous (KP) extinction and the End-Permian extinction
Permian- over 50 % families and 90 % species, 65 million years
Causes- ?
(look up criteria for mass extinction in book, it’ll be on test)
What is systematics?
The study of the evolutionary history of organisms, including any & all relationships among them.
Know our system of biological classification
Keep pond clean or froggy gets sick
What is a binomial species name? How is it written?
Know the difference between genus name andspecific epithet.
What is the 6th mass extinction
Modern world extinction caused by humans through the transformation of landscape, over exploition of species, pollution, and the introduction of alien species. WE ARE OVERPOPULATED
Know the difference between genus name and specific epithet.
Homo sapiens (Genus then specific epithet)
What is a phylogeny?
The evolutionary history & pattern of descent of a group of organisms.
Why do we construct phylogenetic trees? Illustration
of the historical pattern of descent of such a group.
Illustration of the historical pattern of descent of such a group.
Why is phylogenetic reconstruction a non-trivial task, i.e., why is it difficult?
Branch
represents a population through time
Node-
Indicates a speciation event at the end of a branch, splits into two or more species.
Tips-
species or taxons of the present or a specie that has gone extinct
root-
sister group
outgroup
How are phylogenetic trees constructed?
Differentiate between phenetics and cladistics
How do you determine character polarity?
Use the outgroup method
What is an ancestral character?
A characteristic that existed in an ancestor, the outgroup, 0 on chart
What is a derived character?
One that is a modified form of the ancestral trait found in a descendant. 1 on chart
What is a synapomorphy, why are they important?
A shared derived trait, it’s what used to place organisms into monophyletic groups (clades)