Exam 3 Flashcards
Species can have a range of relationships with each other, from _________ to ________.
antagonistic, mutualistic
What is reciprocal selection?
Selection that occurs in two species, due to their interactions with one another
The anemone and the clownfish is an example of a _______ relationship
mutualistic
Describe our relationship with our gut microbiome
- Mutualistic
- Positive frequency dependent selection
How is our relationship with our gut microbiome mutualistic?
- They (the bacteria) rely on our unused metabolic products for their own metabolism.
- Provide us with a myriad of benefits that are essential for optimal human health.
Scavengers partake in what type of relationship?
Commensalism
What are some examples of antagonistic interactions?
- Predator/prey
- Herbivore/plant
- Deceptive pollination
- Host/parasite
What food do you eat that has “evolved” to be eaten? (i.e. would go under mutualisms)
Fruits!
Describe deceptive pollination. What type of selection is it?
- Negative frequency dependence
- Insect is attracted by color, but is ultimately tricked
Describe commensalism
positive / neutral
Describe mutualisms
positive / positive
Describe antagonisms
negative / positive
What type of relationship is rarest?
Commensalism
Species in ecological relationships with other species produce ____________, and adapt to one another in a process known as ___________
reciprocal selection, coevolution
Humans and dogs have what type of relationship?
Mutualistic
How can we focus on how dogs have changed in relation to us?
By comparing with wolves
________ is an example of co-adaptations due to reciprocal selection
Pollination
Pollinators ______ on flowers to attract them
select
Flowers _______ colors, food rewards that attract
evolve
Flowers _______ on the pollinators to transfer pollen
select
Pollinators _______ hairiness, body shape, and behavior that effectively transfer pollen
evolve
What changes when evolution is interactive?
Co-adaptations due to reciprocal selection
Deceptive pollination is another example of
co-adaptations due to reciprocal selection
What kind of interaction is deceptive pollination?
Can be commensalism or antagonistic
What are some evolutionary changes due to deceptive pollination?
- Selection on insect to learn about deception
- Selection on plant to be more attractive and deceptive
What example of coevolutionary alteration did we learn about?
Cuckoo birds evolving to avoid the nests of birds that have evolved to recognize the cuckoo eggs
Mutualistic species exert _____________ on one another, and the rapid ________ that results can be similar to an “arms race” onlywithout the antagonism
positive frequency dependent selection, coevolution
Mutualistic interactions are vulnerable to the invasion of _________, that spread rapidly and lead to the collapse of the mutualism.
cheaters
Host and parasite (or pathogen) may generate _____________ on one another, maintaining genetic variation in both populations.
negative frequency dependent selection
Predators sometimes switch between prey, resulting in sequential bouts of __________.
pairwise coevolution
Define attenuated
weakened or thinned (reduced virulence)
Is it always beneficial for a virus to have high virulence?
No because if the host dies too quickly, the virus cannot move to another host and it will die too
Describe the use to the myxoma virus in Australia
- The virus was introduced in order to get the rabbit population under control
- The virus had a very high virulence at first
- Virulence went down after awhile
Two species of Joshua Tree diverged due to….
two sister species of pollinating moths specializing on trees in different areas
Coevolution can increase…
biodiversity
Coevolution can drive…
extinction
How/why does coevolution drive extinction?
Within coevolution, two species become more and more specialized for each other. If one organism disappears/dies, the other one is likely to as well
Coevolutionary relationships can increase biodiversity as…
genetic diversity among populations diverges
What are endosymbionts?
Mutualists that must live inside coevolutionary partners
________ = how two species become one
Endosymbiosis
Describe the relationship between leaf hoppers and the bacteria that live within them
- Bacteria in leaf hoppers help with digestion
- Bacteria have lost a large part of their genome – retain genes needed to help leaf hoppers with digestion
What two cell organelles are thought to have started as bacterial endosymbionts?
Chloroplasts and mitochondria
Mitochondria evolved from…
free-living bacteria
What was interesting about the gopher and lice populations?
- The lice are kind of considered endosymbionts
- When the gopher populations split, the lice populations living on them did as well
What are retroviruses?
Retroviruses create an RNA copy of their genome, turn it into DNA and insert into genome of a host cell (instructs cell to make viruses)
Retroviruses catalyze coevolution between…
different parts of a genome
How can genomic parasites be passed down from generation to generation?
If it infects sperm or egg cells, genes from virus can be passed down generation to generation via the genome
Endogenous retroviral DNA makes up about ____% of our genome
8
Endogenous retroviral DNA makes up ____ times more of the human genome than the 20,000 genes that encode proteins!
4
_________ can behave like genomic parasites
Transposons/mobile genetic elements
What are “domesticated” parasites?
Originally DNA hurt host, but then takes on function that benefits host
___________ are mutualistic organisms that live within the body or cells of another organism
Endosymbionts
_________ and _______ are endosymbiotic bacteria that coevolved with their hosts until they became “organelles”
Mitochondria, plastids
Endogenous retroviruses and mobile genetic elements have…
coevolved with their hosts genomes
What are some of the benefits (for animals) of living in a group?
- Increased vigilance
- Dilution effect
- Enhanced defense capability
- Cooperative foraging/hunting
- Improved defense of critical resources
What are some of the costs of living in a group?
- Increased conspicuousness to predators
- Increased competition for mates
- Increased competition for resources
- Decreased certainty of maternity/paternity
- Increased risk of transmission of disease/parasites
In the prisoner’s dilemma, describe what type of social interaction is occurring.
- Cooperative
- Selfish
- Spiteful
- Altruistic
- Cooperative: both actor and recipient benefit
- Selfish: actor benefits, recipient is harmed
- Spiteful: both the actor and recipient are harmed
- Altruistic: actor is harmed, recipient benefits
What is the problem of altruism?
What is good for the group is not always good for the individual
How are alarm calls considered altruistic?
- Alarm calls help all the individuals in the area as they notice the predator.
- Alarm calls attract the predator to the caller!
Why wouldn’t altruistic behaviors be removed by natural selection?
Because overall, it is good for the group/beneficial
Why do females give more alarm calls than males?
- Kinship!
- Females often stay put after sexual maturity and have more ties to those around them
What is Hamilton’s rule?
- A central theorem of inclusive fitness (kin selection) theory. It predicts that social behavior evolves under specific combinations of relatedness, benefit and cost
- An altruistic allele will spread if (Br – C > 0)
In Hamilton’s rule, what do B, r and C represent?
- B = = benefit to recipient
- r = coefficient of relatedness (between actor and recipient)
- C = cost to actor of behavior
How is the “r” in Hamilton’s rule calculated?
Genetics
What is r equal to for half siblings? Full siblings? Cousins?
- Half siblings = 1/4
- Full siblings = 1/2
- Cousins = 1/8
Based on coefficient of relatedness which of the following should you save (no cost to yourself) to increase your indirect fitness the most?
1) Both maternal and paternal grandmothers
2) One full sibling
3) 5 cousins
4) An aunt and her husband (uncle)
5 cousins
T / F : parents are more likely to care for genetically related children
T
What is inclusive fitness?
A theory in evolutionary biology in which an organism’s genetic success is believed to be derived from cooperation and altruistic behavior
How can adoption be considered an altruistic behavior?
If kin/relative is adopted
Kin selection makes the explicit prediction that…
animals should extend their help to relatives
What is the problem with kin selection?
Must be able to distinguish/recognize kin from unrelated individuals
What are some mechanisms of kin recognition?
- Physical proximity
- Odor
When might physical proximity might not be enough for recognizing kin?
If dispersal, multiple mating or inter-brood aggregation has occurred
Can cooperation evolve in non-kin groups?
Yes!
What is game theory?
- A theory developed by economists
- Assumes that “players” behave rationally and attempt to maximize some criterion (e.g. profit)
- In terms of evolution, natural selection replaces rationality and fitness replaces profit
Define strategy
a complete specification of what an individual will do in any situation (behavioral phenotype)
Define/describe Evolutionary Stable Strategy
a strategy that if adopted by all members of a population, it can not be invaded by an alternative strategy
What is the dominant strategy for the prisoners dilemma?
For both players, the dominant strategy is to confess
What is the “dilemma” of the prisoners dilemma?
The outcome is not efficient (there is no other outcome that pays all players more).
How is cooperation among non-kin possible?
- Repeated interactions with same individuals
- Many opportunities for altruism to occur
- Individuals have good memories
- Potential altruists interact in symmetrical situations
What are some examples of tit-for-tat in nature?
- Egg swapping in hermaphroditic fish
- Blood sharing in Vampire Bats
- Reciprocal grooming in Impala
Can altruism benefit the actor? If so, when?
Yes, due to kin selection
Which of the following is the best example of an altruistic behavior?
A. Jumping in front of a car to pull your child to safety.
B. Donating money anonymously to your niece’s college fund.
C. Donating blood and wearing a sticker that indicates you donated blood.
D. Blinking your lights at on coming traffic to indicate there is a policeman up the road.
E. All of the above fit the definition of “altruistic”
D. Blinking your lights at on coming traffic to indicate there is a policeman up the road.
Which of the following statements are true about cooperation?
A. Related individuals are going to cooperate in almost all situations as they have some genes in common.
B. Cooperation is unlikely to evolve in unrelated individuals.
C. Cooperation is more likely to evolve if individuals interact only once or a few times.
D. Forgiving is an important component of a strategy of cooperation among non-relatives.
D. Forgiving is an important component of a strategy of cooperation among non-relatives.
Game theory model “prisoner’s dilemma” has been used to study the evolution of __________.
cooperation
What is the Catarrhini synapomorphy?
Narrow strip of flesh separating nostrils
What are synapomorphies for apes?
- Relatively large brains
- Absence of a tail
- More erect posture
- Greater flexibility of hips and ankles
- Structure of arms and shoulders
What are synapomorphies for great apes?
- Elongated skull
- Enlarged brow ridges
- Shortened but stout canine teeth
- Fusion of certain bones in the wrist
- Enlarged ovaries and mammary glands
- Reduced hairiness
T / F : Phylogenies of genes (and other individual traits) are not necessarily the same as species
T
How do we reconcile the data to determine the species tree for humans?
Sequence more genes!
According to Sarich and Wilson, the dated split from old world monkeys and fossils was ____ years ago
30 million
Gorillas diverged _______ years ago
6.4 million
Homo and chimps split _______ years ago
5.4 million
Humans shared a common ancestor with chimps 5.4 million years ago. What behaviors/characteristics did these ancestor exhibit?
- Knucklewalker
- Broad, fruit-based diet
- Lived in a range of habitats
- Used tools to obtain and process food
- Hunted
- Culture (behavior that is taught and learned and varies among populations)
Compare/contrast chimps and bonobos
Chimps
- Male dominated, strategic alliances, fight
viciously, stalk and kill rivals, primarily
heterosexual
Bonobos
- Female dominated, less violent than
chimps, have sex in all possible
combinations and not just for
procreation.
How does the karyotype of humans differ from chimps and gorillas?
- 23 pairs in humans versus 24 pairs in other apes
- Due to fusion of two chromosomes
_____ DNA sequence similarity between humans and chimpanzees
98.9%
What explains morphological, behavioral and intellectual differences between humans and chimpanzees?
While there is a 98.9% DNA sequence similarity, only 29% protein coding
What organs (in humans and chimps) have similar divergences in gene expression? Differences?
- Similar: liver and blood
- Different: brain
Why is the fossil record of human line much better than that for gorillas and chimps?
Because we can live in more readily preserved (drier) environments
Describe some of the skeletal modifications for bipedal locomotion in humans
- Increasing rigidity and stiffness in spine
- Changes in the pelvis for muscle attachment
- Foramen magnum - bottom and center of skull region
- Longer leg bones relative to arms
What differences arose in human lineage after split from chimps?
- Skeletal modifications for bipedal locomotion
- Increases in cranial volume (larger brains)
- Loss of prominent brow ridges
- Flat face
How old is Lucy?
~4 million years old
How does Lucy compare to chimps in terms of cranial volume?
The same
What characteristic does Lucy share with humans? What is the evidence for this?
- Upright bipedal locomotion
- Evidence: long legs, curved pelvis, strong arches, knee modified for vertical weight bearing, big toe long and forward pointing AND…fossil footprints!
What is the significance of Lucy’s brain size and upright bipedal locomotion?
Tells us that we evolved the ability to walk upright before we evolved larger brains
What “Lucy” characteristics were lost in the lineage giving rise to Homo?
- Diastema between canines and incisors
- Confluent jaw and neck muscles on the skull
- Large canines
Lucy helped to move ________ to base of tree
bipedal locomotion
Describe Paranthropus “robust forms”
- Side branch of human evolution
- Specialized for herbivory (huge molariform teeth, massive jaws)
- Extinction ~beginning of ice age
Describe Homo habilis
- Larger brain
- Shorter wider jaws
- Bony nose bridge
The emergence of human line (genus) known as Homo was ~______ years ago
2.3 million
Contrast Paranthropus and Homo in terms of brain size
- Both had large brains
- Diet differences (Paranthropus has herbivorous diet, leading to tradeoffs in energy between gut and brain)
- So, similar sized brains, but differences in brain power
If modern humans diverged 1 million years ago, what 3 predictions must be true?
1) Relationship between current and extinct by region.
2) Split one million years ago.
3) Each region equally genetically diverse (no founder effect)
Which was correct: the African replacement model, or the multiregional evolution model?
- The African replacement model
- There were not similar, distinctive traits found within a region (modern and archaic)
How long ago did modern humans and Neanderthals split?
~500,000 years ago
When did the diversification of modern humans start?
Within the last 170,000 years
How do we know that modern humans first originated/evolved in Africa?
Genetic diversity is much higher in Africa
What is the time of the African split?
~75,000 - 287,100 ya
African populations having more allelic diversity supports the idea that what took place?
Founder effect
___-___% of all the DNA in people of non-African ancestry originated with our thick-browed cousins (Neanderthals)
1-4%
When did the interbreeding of Neanderthals and modern humans occur?
45,000 to 80,000 years ago and before humans spread out across Asia
How old are the oldest Neanderthal remains discovered? Where were they found?
- 225,000 years old
- Germany
Was tool use unique to Homo sapiens?
No! Neanderthals also used tools, although they were primitive in comparison
What evidence is there to support that Neanderthals had similar communication methods to Homo sapiens?
Identical hyoid bones to the ones we have
Did humans have larger brains than Neanderthals?
No, brains were similar sizes
What is one possible difference between humans and Neanderthals that allowed us to continue living?
Culture!
Although humans and Neanderthals had similar sized brains…
our neurology was most likely different
What two human characteristics have been associated with the extinction of many other animals?
Eating meat and having larger brains
What are some of the body’s “ailments” that are in fact evolved defenses?
Pain, vomiting, morning sickness, fever, low iron
Describe the conflict between parasite and host
- The host’s immune system remembers the structure of pathogen’s proteins.
- Immune system selects for parasites that can evade detection.
How do flu strains survive?
- Find naïve hosts (not exposed to their version of hemagglutinin, coat protein).
- Produce novel amino acid sequences in the protein hemagglutinin.
- Flu viruses evolve a million times faster than mammals
What was different about the flu strains that survived and the ones that went extinct?
For those that survived, most of the amino acid replacements were in the antigenic sites
When comparing the 18 codons in the hemagglutinin gene of the flu virus, the replacement to synonymous mutations suggest that what type of selection was occurring?
Positive
How do viruses reproduce?
- Manipulate receptors on cell so the cell engulfs the virus
- Virus’s genes released from protein shell
- Host cells start making viruses
Why are viruses so diverse?
- High mutation rates
- Gene mixing
In what ways are viruses adapted to hosts?
- Function best at host temperature
- Infect certain cells the best
What allows/would result in a virus strain becoming a pandemic virus strain?
Radical changes in the structure of hemagglutinin (not seen before by human immune system), meaning it could then infect everyone alive
How could a virus radically change its hemagglutinin structure?
If two virus strains in same individual cell can recombine, they can have nucleotide proteins specific to humans, but hemagglutinin protein from another organism (no humans immune response)
Where do scientists think Influenza A (the Spanish flu) originated from? How did they determine this?
- Birds
- Sequencing from bodies in Alaska
What was interesting about the 1997 Bird flu?
- For the first time, an influenza virus was found to spread directly from birds to people.
- So far, the virus has not adapted to spread easily between humans.
Describe the 2009 Swine flu
- A combination of a Eurasian swine flu virus with another strain that was itself a mix of bird, swine and human flu virus.
- Killed more than 18,000 people around the world.
Nucleoproteins are ______ specific
host
Describe a phylogeny based on nucleoproteins
Groups viruses by the host in which they infected
What does it mean if a host species is found in multiple clades?
The strains can trade genes
Why is it important to know origin of virus causing epidemic?
- Important for knowing the function of the virus
- Important for understanding how to prevent the spread of zoonotic diseases
By what mechanisms can antibiotic resistance evolve? Give examples
- Loss of function mutation (ex: tuberculosis and isoniazid)
- Gain of function mutation (ex: genes that code for enzyme that breaks down ampicillin)
If it costs for bacteria to evolve resistance, what would we see?
If resistance costs, antibiotic sensitive bacteria grown in absence of antibiotics should have higher fitness than those that are resistant
If it costs for bacteria to evolve resistance, what would we see if antibiotics were not used anymore? Is this the reality?
- Strains would evolve back into being susceptible
- Happens, but only for a couple generations
What happens to bacteria’s sensitivity to antibiotics over many generations?
The bacteria evolve around the cost
How do you avoid food-borne bacteria?
Wash or cook food before you eat it
When should you use antibacterial soaps?
Hospital settings only
Should you use antibiotics for viral infections?
Absolutely not. Not only will it not help, it very likely could lead to antibiotic resistance
Best use of antibiotics when you have them?
Narrow range if possible
How should one handle patients that are resistant to several drugs?
Strict isolation
Why is virulence so variable?
It can evolve!
Define virulence
The “harm” done by pathogen to host
T / F : Virulence is highly variable across human pathogens
T
What are the three hypotheses for the evolution of virulence?
- The coincidental hypothesis
- The short-sighted hypothesis
- The trade-off hypothesis
What does the coincidental hypothesis state?
Virulence is not the target of selection itself but an accidental by product
What does the short-sighted hypothesis state?
Traits that enhance fitness within a host are not necessarily good for transmission
What does the trade-off hypothesis state?
Natural selection should select for a balance between costs and benefits of harming hosts
More opportunity for horizontal transmission is associated with _______ virulence
higher
Which hypothesis is supported by the fact that diseases carried by vectors on average are more virulent?
The trade-off hypothesis
Can human behaviors select for more virulent diseases?
Yes!
The easier you make it for a pathogen to be transmitted…
the more virulent it can become
Genetic diversity of cancer samples can tell you about the…
ancestral state
A cancer with more genetic diversity…
is older/the cancer of origin
A blood sample from a patient detects low iron. Which of the following is something a physician should do if they are seeing the patient for the first time? Why?
- Suggest the patient takes iron supplements.
- Send the patient to a cancer specialist.
- Check the patient for heart disease.
4.Realize that not everyone will have the same iron levels and note that for this patient it will be low in future as well. - Test the patient for a bacterial infection.
- Test the patient for a bacterial infection.
(Iron is sequestered to the liver during an infection to make the host environment less hospitable for the virus. Low iron is an evolved defense against a bacterial infection.)
An important strategy of mammalian antimicrobial defense is based on…
depriving pathogens of essential nutrients
What are the two evolutionary perspectives on fevers? Describe them. Which is more likely?
- Fever is a manipulation of the host by the pathogen
^ Increases temperature so pathogen can
grow better - Fever is adaptive response of host to pathogen
^ Host’s immune response better at
higher temperatures, and some bacteria
can not tolerate high temperatures
^ More likely
Explain how morning sickness is an evolved defense
Protects embryos from chemicals in some foods that can compromise development
Explain how depression is an evolved defense
Selected for in individuals that need to more or less “hibernate” through cold-dark winters
To what environment are humans adapted?
It depends on the trait!
What two hypotheses could explain why breast cancer is not selected out of the population?
- Breast cancer is caused by pathogen
- Breast cancer is a disease of civilization
How does menstrual cycling relate to breast cancer?
- Menstrual cycling appears to increase risk of breast cancer
- Combination of hormones present during cycle stimulates cell division in the milk ducts
- More cell division means more opportunities for mutations that can cause cancer
What is one explanation as to why breast cancer rates are so high? What evidence supports this?
- Women’s bodies may not have evolved (by natural selection) to tolerate long periods of continuous menstrual cycling.
- West African women with menstrual patterns similar to Dogon women have breast cancer rate 1/12 as high as North American Women.
The stress response increases…
metabolic rate and alertness
The stress response inhibits…
growth and reproduction
What can long term, high stress levels result in?
Decreased immune system and shrunken neurons
The benefits of stress depend on _____
context!
Which of the following is TRUE about what we learned from evolution to determine which flu vaccines to make?
A. Evolution of antigenic sites is due to genetic drift.
B. Because the viruses can evolve, it is not possible to predict which will be most common.
C. Vaccines can only be made for flu strains once they become the most common and problematic.
D. Flu strains that are going to be prevalent are those that have the most mutations in the hemagglutinin antigenic sites.
D. Flu strains that are going to be prevalent are those that have the most mutations in the hemagglutinin antigenic sites.
How did researchers (2006) figure out the source of the Spanish Flu (1918)?
A. Sequenced individuals that are still carrying the flu virus with them today.
B. Compared sequences of today’s bird flu virus with those found only in birds
C. Sequenced tissue form a frozen body of who died of influenza in 1918 in Alaska.
D. Using a phylogeny of all viruses they could identify the source of the Spanish flu virus.
C. Sequenced tissue form a frozen body of who died of influenza in 1918 in Alaska.
What is the best solution to the problem of bacterial resistance to antibiotics?
A. Use antibiotics often as it is very costly for bacteria to evolve resistance.
B. Get all the doctors to agree to stop using the antibiotics for awhile so bacteria will evolve to be sensitive again
C. Always use broad range antibiotics.
D. Restrict unnecessary use of antibiotics.
D. Restrict unnecessary use of antibiotics.
All else being equal, which of the following is found to often be the case when the opportunity for transmission increases to the virulence of a pathogen?
A. More easily transmitted, more virulent
B. More easily transmitted, less virulent
C. There is no relationship
A. More easily transmitted, more virulent
What does the higher genetic diversity in the adenoma tumor as compared to the colorectal carcinoma tumor tell us?
A. The adenoma tumor is more likely to cause cancer.
B. There is stronger selection on the adenoma tumor.
C. The adenoma tumor is older.
D. The carcinoma tumor produced the adenoma tumor.
C. The adenoma tumor is older.
Why did the authors choose to test their hypothesis with dogs?
Their long relationship with humans; convergent evolution with humans; previous studies suggesting they may be able to attribution “reputation” to humans
What did the “selfish” experimenter do different than the “generous”?
They ate the food in front of the dog!
What were their main results (experiment 1 and 2 of Reading #9 which discussed dogs and behavior)?
After the second training, the dogs approached the “Generous” significantly sooner as compared to the “Selfish”
Why is recognition important for cooperation?
Recognition of kin (one way for cooperation to evolve) but in cases of non-kin, without recognition the ESS of playing once with someone you don’t know how they will behavior is to not cooperate…Otherwise, you end up as the “sucker”
Which of the following is a potential outcome of “reciprocal selection”?
A. Two species becoming dependent on one another through coadaption.
B. Predator-Prey coevolutionary arms race.
C. Reduction of virulence.
D. Increases in biodiversity.
E. All of the above
E. All of the above
How can we use phylogenies to determine if two clades of organisms have coevolved?
A. When you compare the phylogenies of two clades they mirror one another in relation to where speciation has occurred.
B. You can count up the number of species and see if is the same in both clades.
C. There should be fewer evolutionary changes in the two clades than expected by chance.
D. Phylogenies are useful within a clade, but not for comparing the evolution of two clades
E. One of the clades should have many more species than the other.
A. When you compare the phylogenies of two clades they mirror one another in relation to where speciation has occurred.
Which of the following are necessary for cooperation to evolve and become an ESS, as we have learned from the “Prisoner’s Dilemma” game.
A. Individuals can only play one another one time.
B. Both individuals need to start out as defectors (confess, or not cooperating).
C. Individuals need to be able to recognize one another at least one interaction back.
D. One player has to always cooperate (remain silent).
E. We have learned from this game theory model that cooperation only evolves if individuals are related.
C. Individuals need to be able to recognize one another at least one interaction back.
Which of the following was found in the Carballo et al. study of dogs in relation to cooperation with humans?
A. Dogs have a hard time recognizing humans that are cooperative.
B. Pointing at food sources is not something dogs understand.
C. Dogs do not distinguish between humans based on gender.
D. Our relationship with dogs is not necessarily mutualistic.
E. None of the above.
E. None of the above.
Which is FALSE about the evolutionary relationships among Catarrhini clade?
A. Humans belong in this clade.
B. New world monkeys are not part of the Catarrhini clade.
C. Catarrhini includes old world monkeys and the apes.
D. One of the synapomorphies for Catarrhini clade within primates is being diurnal.
E. One of the synapomorphies for the Catarrhini clade is a narrow strip of flesh separating nostrils.
D. One of the synapomorphies for Catarrhini clade within primates is being diurnal.
Which of the following is evidence against the “multiregional” hypothesis (see below) for the evolution of humans?
A. There is more genetic diversity in humans from Africa than other regions across the globe.
B. Fossils found in the different regions where humans are found are not more closely related to the humans in those regions.
C. The genetic differences between the humans from different regions suggests divergence was only 170,000 years ago.
D. All of the above
D. All of the above
Which of the following is TRUE about Neanderthals in relation to current humans?
A. We can only compare morphological traits between these two species.
B. There has been some adaptive introgression from Neanderthals to humans
C. We find more Neanderthal genes on the Y chromosome.
D. All of the introgression between these two species has led to negative genes in humans.
E. Neanderthal genes are more common in humans from Africa.
B. There has been some adaptive introgression from Neanderthals to humans
Which of the following is TRUE about pathogen virulence?
A. There is a correlation between the virulence of a pathogen, and how rapidly it will spread.
B. Virulence does not evolve.
C. Transportation by a vector (like an insect) decreases virulence.
D. Virulence is the extent to which the host can protect itself from infection by the pathogen.
E. Those pathogens that are the most virulent are the least likely to kill their host.
A. There is a correlation between the virulence of a pathogen, and how rapidly it will spread.
Which of the following is true about a human’s stress response?
A. Hormones produced in response to stressors increase resources going to reproduction.
B. Hormones produce in response to stressors decrease metabolic rate and alertness.
C. Long term stress can decrease neurons in the brain.
D. Stress can lead to an increase response of the immune system to pathogens.
E. Long term stress is often due to stressors that the ancestors to H. sapiens evolved with.
C. Long term stress can decrease neurons in the brain.
Which of the following is NOT true about what the authors in the article Seitz et al. (2020) call our “behavioral” immune system?
A. It consists of human behaviors that reduce the risk of contagion.
B. It may not function if contagious individuals show no signs of being sick.
C. The behavioral immune system can make humans intolerant to outgroups.
D. Disgust is part of our behavioral immune system.
E. Our behavioral immune system has been used to engineer most of the tools of modern medicine.
E. Our behavioral immune system has been used to engineer most of the tools of modern medicine.
Why is the DNA from Neanderthals that went extinct 40,000 years ago, found in humans today?
Introgression – or hybridization (mating across species)
Why is the DNA from Neanderthals less likely to be found in Africans?
Our history of “out of Africa” led to some humans living in close contact with Neanderthals
How do we know that some negative genes from Neanderthals were selected out of our species?
Introgression “deserts”
What are some of the positive traits from Neanderthals found in humans today?
Cellular response to UV radiation
What is one of the hypotheses for why there are so few Neanderthal genes on the X chromosome?
- Deleterious genes on X have no counter part for heterogametic sex (males – XY)
- Sex bias (in mating; perhaps as much as a three to one bias towards Neanderthal males mating with modern human females)
