Timing of appearance (anatomy suggests order of evolution)
Examples of evolution on short time scale include __?__.
Resistance in disease causing organisms
Plant resistance to toxins
Lab experiments (fruit flys)
Examples of geographical distribution include __?__. (1)
Organisms closely related are often found in same geographic region ie Hummingbirds in North America
Vestigal structures are __?__.
rudimentary structures that seem to habe lost some or all of their function
ie tail bone in humans
Embryology is a good example of __?__ because __?__.
similarities between organisms
Organisms that are different as adults can have similar embryos (common ancestors use same embryological patterns)
DNA is an example of __?__ because __?__.
all organisms use the same material and mechanisms
Evolutionary biology is important because __?__ (1 idea) especially in the areas of __?__. (3)
It helps us understand ourselves and natural world
__?__ is the scientific foundation of biology which is the foundation of Medicine.
__?__ are the four approaches to looking a medicine in an evolutionary context.
Evolved defenses (Fever)
Conflict with other organisms (co-evolution between pathogen and host + resistance)
Dealing with new circumstances (Introduction to new enviornments + adaptation ie fatty foods and humans)
Trade-offs (def. of "trade-off" ie sickle cell anemia
Evolution helps conservation efforts because it __?__. (4)
Helps decide what a species is
Helps pinpoint areas with greatest biodiversity
Population genetics helps us prevent genetic deterioration of threatened species
Evolutionary biology studies how organisms respond to change.
__?__ are the 5 main Historical contributors to evolution and __?__ are thier ideas.
Aristotle - Scala Naturae
Linnaeus -Scientific names and classification
Cuvier - Extinction and catastrophism
Lamarck - inheritance of acquired characteristics
Darwin - Evolution and a mechanism (Natural Selection)
Scala of nature means __?__. It's flaw is __?__.
Species evolve from imperfect to perfect
Evolution is not progressive nor does it have a direction or goal
Carolus Linnaeus was the founder of __?__ and believed __?__.
Modern taxonomy (placing life into order)
species were permanent creations (non-evolutionary idea)
__?__ was the problem with Linnaeus's ideas.
Fossil record suggested there were species that do not exist anymore and there are new species that didnt exist before.
Georges Cuvier is the founder of __?__ and __?__.
Cuvier grouped animals into __?__ (#) distinct branches which were __?__.
Different layers of fossils suggested __?__ to Cuvier and he created his idea of __?__ to explain the layers. His idea explained the layers by saying __?__.
Extinction (species were not fixed)
Catastrophies occured which eliminated species who were then replaced by others
Lamarck was the first great __?__.
Lamarcks views of evolution were that __?__ (2).
Use and disuse of parts (parts used often got bigger)
Acquired characteristics were inherited
ex. = giraffe necks
__?__ is the flaw in Lamarck's ideas.
Organisms do no inherit aquired characteristics
__?__ are the three ideas that allowed evolution to be discovered by Darwin and accepted by people.
Plants and animals grouped
Extinction was a fact
Geological evidence showed the earth was old enough for evolution
Darwin's voyage on the HMS Beagle was influential for these three reasons?
fossil collection during voyage
Lyell's principles of Geology
collection of animals and plants from different areas
__?__ are the three reasons why the Galapagos showed why evolution explains the patterns of speciation best.
Islands are grouped closely together
all islands are in the same climactic zone
Very different species on each island
Darwin believed in natural selection for these four reasons?
Individuals within a species vary
Some variations are passed to offspring
In every generation more offspring are produced than survive
Survival and Reproduction are not random
Dawins 4 premises for natural selection are demonstrated by the giraffe as __?__.
1. Neck length varies
2. Offspring tend to have similar neck length of parents
3. More giraffes are produced than survive
4. Longer necked giraffes are more likely to survive
The modern synthesis of Natural selection states __?__.
Alleles that increase an organisms fitness are passed on more often/increase in frequency over time.
How do Darwins finches prove each of his postulates?
1. Beak size is variable
2. Beak size in offspring is similar to parents
3. Drought killed 84 % of pop.
4. Surviving birds had thick beaks (NOT RANDOM - fewer small seeds after drought)
The three modes of selection are __?__.
1. Directional - one extreme favored
2. Stabalizing - extremes are eliminated (suggests already well adapted)
3. Disruptive - selection for extremes (hard to maintain)
An example of Directional selection is the __?__ becuase__?__.
Lichen on trees died from polution so dark moth was selected for
An example of stabalizing selection is __?__ because __?__.
larvae inside medium sized gall survived at highest rate
Human birth weight
Examples of disruptive selection include __?__.
seedcracker finch (pyrenestes)
__?__ are the 5 forces of selection.
Genetic drift vs Natural selection.
Genetic drift is the random sorting of heritable characters
N.S. is the non-random sorting of heritable characters
Phylogenies are built and evaluated using __?__ and __?__.
Characters (must be heritable)
Phylogeny: the evolutionary history of a group of organisms represented in a tree diagram
__?__ are the three things that can cause similarity.
Common ancestry: Homolgy
Convergence: independant ecolution of similar character in two or more lineages (Homoplasy)
Reversal: Reversion to an ancestral form of a character due to selection or mutation (Homoplasy)
An example of homology is __?__
forearms of tetrapods
An example of convergence is __?__.
wings in different taxa
Shark and killer whale (shape, flippers and tails)
An example of reversal is __?__.
Archaeopteryx (first bird - claws) --> Most birds (no claws) --> Hoatzin (clawed bird)
Parsimony minimizes the number of __?__ which __?__.
the number of evolutionary changes that occur which limits the number of homoplasies.
Parsimony groups organisms based on characters that are __?__.
Shared and derived
Derived: evolution happens when an ancestral character evolves into a derived character
Synapomorphy: Shared, derived character
Define plesiomorphy, apomorphy, synapomorphy
Plesiomorphy: Ancestral character
Apomorphy: Derived character
Synapomorphy: Shared, derived character
Parsimony defines __?__ groups which consist of __?__.
Monophyletic groups which consist of a common ancestor and all of its decendants
What are the modes of speciation?
Allopatric "other place"
Parapatric "beside place"
What is Allopatric speciation?
Populations become seperated by a physical barrier and the evolve reproductive barriers
What are two types of Allopatry + examples?
Vicariant: pop divided into two widespread populations by a physical barrier - no dispersal - result = 2 large pop
ex: freshwater fish and snapping shrimp (land bridge formation)
Peripatric: A small colony disperses from a widespread population to a new area and evolves reproductive isolation Physical barrier - dispersal - 2 small pop.
Usually caused by genetic drift/founder effect
What is secondary contact?
When species reconverge after speciation
How can you tell if a vicarian event ocured by looking at a phylogeny tree
Closest relative will be in different geographic area
Why are elephant seals and example of peripatric speciation?
Hunted to samll number
small colony near Mexico - Founder effect
very small genetic diversity (population bottleneck)
What is Parapatric Speciation?
Strong selection causes a continuous population to divergePopulations are contifuousNo physical barrier (gene flow) speciation between niches within ecosystem
What is a Hybrid Zone?
When a species diverges, but populations come back together. The area the two pop meet is the hybrid zone (secondary contact)
What does a hybrid zone indicate?
Primary differentiation (parapatric speciation)
Secondary contact between two formally isolated populations (Allopatric Speciation)
What is Sympatric speciation?
No geographic separation
What is Hybridization?
Model of speciation
Two parental species hybridize and produce offspring that can breed with each other, but are reproductively...
Much more common in plants (rare in animals)
Speciation by polyploidy is caused by __?__.
Errors in mitosis or meiosis resulting in diploid gametes instead of normal haploid gametes.
Individuals with diploid gametes mate with each other and produce polyploid offspring
Resulting individuals can not breed with progenitors (parents), but can breed with each other
Species concepts matter because they allow __?__ and __?__.
Identification and understanding of biodiversity
Taxonomic status often dictates conservaion priority
__?__ are the three steps to defining species.
1. Observe morphological or molecular variation
2. Group individuals into taxa
3. Rank taxa into hierarchy
Define the Biological Species Concept
BSC: Actually or potentially interbreeding populations that are reproductively isolated (lack of gene flow) from other such groups
Problems with the BSC include: (5)
fossil species dont apply
Hybridization (especially plants)
Evolution prior to reproductive isolation
Isolated pop. cant be tested
Define Phylogenetic Species Concept
PSC: The smallest diagnosable cluster of organisms within which there is a parental pattern of ancestry and decent
Smallest monophyletic group
Define Diagnosable, Ancestry and decent
Diagnosable: characters differentiate species (Synapomorphies)
Ancestry and decent: share history
The PSC over comes which of the problems presented by the BSC?
Criticisms of the PCS include: (3)
Phylogenies difficult to obtain
Species specific trait may be trivial
Will name too many species
BSC vs PSC
BSC: reproductive isolation; predicting future; Based on morphological differences, groups individuals into taxa. If they hybridize = subspecies
PSC: Characters are important, monophyly; reconstruct past; Morphology reveals groups with independant evolutionary histories, ranks species wither hybridizing or not
What is the giraffe example and what does it demonstrate?
6 different colors in different geographic regions, all can mate = 1 species in BSC
Different species are adapted to different regions = 6 species in PSC
Define Ring distribution and problems + examples
Ring distribution: Species occupy an area that forms a ring around a geographical location that overlaps at the ends
Problem: all neighbors interbreed accept at ends - How should species be differentiated?
Ex: salamanders and Greenish warbler (not ring, but hybrid zones dont breed)
What is the issue with recognizing killer whale species?
all interbreed, have low mtDNA seq divergence, but inhabit different regions and have character differences. Under PSC = 3 species
What issue does hybridization bring up? Give examples
Is the hybrid a genetically unique individuals making them a new species or are they the same species because they can mate with the originals.
Ex: orioles (interbreeding may be ancestral); Flickers (same thing); Red wolf
Is development part of modern synthesis? Why not?
Geneticists and Developmental biologists do not communicate
Define Ontogeny; How does this relate to Haeckel's law? Who refuted this law and why?
Ontogeny: development of an organism from embryo to dev
Haeckel's law: is a hypothesis that in developing from embryo to adult, animals go through stages resembling or representing successive stages in the evolution of their remote ancestors (Ontogeny recapitulates phylogeny)
Von Baer: No functional equivalent of fish, amphibians, reptile stage in humans - all embryos are different
Changes in form by geometric transformation
__?__ are the two reasons evolutionists are interested in development.
1. Minor changes in regulatory genes can have major effects on phenotypes
2. Development may constrain morphological evolution
__?__ are the three patterns of morphological development.
3. Mosaic evolution
Individualization: When repeated structures become individualized; aquire distict identities
Ex: Homodont --> Heterodont teeth
Individualization is often a result of __?__ which means __?__.
Dissociation: evolutionary change in development where features acquire more independent genetic control
Ex: If bill length and thickness are under same genetic control, larger bill length will also give longer bill length. BUT if they are DISSOCIATED you can get longer bill withough a thicker one.
Define Mosaic Evolution
Mosaic Evolution: When a region under tight genetic control undergoes dissociation, different parts can undergo evolutionary changes more independently
What happens when dissociation takes place
Define Heterochrony and give examples
Heterochrony: An evolutionary change in the timing or rate of developmental events
Can affect may characters simultaneously or few characters
Ex: Lower jaw sizes in horses over time got bigger
Allometry: Different traits that grow at different rates
Ex: babies head is large and grows slowly in relation to rest of body
Ex: Irish Elk antlers - can predict antler size from body size
Development: the means by which genetic change is translated into phenotypic change
Knowing the rules of development allows the explination of many evolutionary novelties - what genes are responsible for evolutionary trait
Beak evolution in Finches is regulated by __?__ proteins.
Calmodulin - length
BMP4 - width
+ = wide long beak (positive gene for two prot.)
Hox genes are __?__. (3)
Each controls the trx of numerous other genes
Do not encode structures, they provide positional information (tell cell where it is in body)
How do hox genes present in evolution of different species? (3)
Many different species (Mouse, fruit fly, Jelly fish) have homologous hox genes.
Not everyone is present, but the shared genes are in the same locations and appear in the same order.
Within a species some hox genes may be missing (A single species does not have to have exactly the same Hox genes)
The change in number of hox genes allowed vertebrates __?__.
Greater morphological complexity
How does the change in Hox target gene relate to the hox gene itself?
The target gene may change dramatically but the hox gene remains relatively unchanged
Ex: The same hox gene controls the development of eyes for flys and mammals, but the two types of eyes are very different
What molecular change in the baleen whale tooth gene took place and what was the result?
resulted in tooth loss
Sexual dimorphism is puzzling because __?__.
It cannot be explained by natural selection
More visible to predators
Assymetry in sex means __?__.
One of the sexes invests more in their offspring
Usually female (eggs and pregnancy)
1. Males attempt as many matings as possible to increase reproductive success
2. Females are selective in their matings to insure reproductive success
Ex: Few males become fathers while all Females have offspring
What is role-reversal and give an example.
Role reversal: Males provide parental care and choose females. This means few females have most of the mates + offspring
Conflict is driven by parental investment rather than gender
Females prefer mates with exagerated traits that may be dangerous to the male because __?__.
The trait is a signal of the males fitness
Ex: Birds of Paradise
What is the Natural selection vs Sexual selextion conumdrum?
Choose trade-off between individual survival or sexual selection