BIO exam 4

Tribe Homonini includes all of the following present-day organisms, EXCEPT ______.

Gorillas

What are the characteristics of primates?

Group of mammals: Forward-facing eyes Dependence on stereoscopic vision Reduced sense of smell Adaptations for climbing • Grasping digits Opposable thumbs Large brain size relative to body size Slow developmental rate Long life span Lineage: lemurs and lorises, monkeys, apes

What were some features about Homo habilis, H. erectus, H. neanderthalensis that was mentioned in the lecture?

Homo habilis: first homo to use stone tools Homo erectus: use of fire Neanderthalensis: Eurasia

Match the species of Homo species with the characteristics they are important for or true about them.

Homo sapiens—the only homo species to reach the Americas Homo habilis—the first to use stone tools Homo erectus—probably first to use fire Homo neanderthalensis—evolved and lived only in Europe

Explain what is the problem with the phrase "humans evolved from chimpanzees?

Humans and other hominids have a common ancestor Chimpanzees are the product of one lineage of that ancestor Chimp and human populations continue to evolve in the trajectory that their environments select for Two currently living species do not evolve into each other

Daniel Fairbanks video: "Everyone is African" is a statement that reflects which of the following?

Humans evolved in Africa, and all humans are genetically very similar.

Suppose tastebuds were under selection pressure in the modern word, and if medical intervention was absent, how might the human population evolve with respect to this trait?

Humans may lose their preference for sweet foods

D. Based on all three graphs above, how do fever suppressors affect how our bodies fight off pathogens

If fever is adaptation against pathogen, taking the fever reducer actually interferes with the body's natural immune response to combat the pathogen. Taking the fever reducer seems to prolong symptoms and reduces the production of antibodies that are needed to recover from the illness.

When do we say two populations belong to different species?

Individuals of the different populations CANNOT interbreed NATURALLY OR Individuals of the different populations CAN interbreed naturally, but... a) do not produce offspring, or b)the offspring do not survive, or c) the offspring are not fertile.

Whaat were the constraints preventing early hominins from having large brains

Insufficient calories to support the maintenance of a large brain

Elaborate ornaments and armaments are most likely to be found in populations that are subject to which of the following conditions?

Intense competition for mates, When there is intense competition for mates, there wil be intense selection for elaborate traits.

LECTURE 20

L21 speciation, L22 human evolution, L23 human adaptations, L24 skin color, L25 evolutionary medicine

Which of the following adaptations have fitness costs to humans?

Large brains, upright spine, narrow hips

Describe the impacts of modern food on human health and link it to our evolutionary history.

Lots of food now and have preference for foods that were once limited Now these foods people eat too much and cause obesity.

Why are only males in most animal species brightly colored?

Male fitness is limited by how many females they can mate with; males that attract female attention have higher fitness. AND Female fitness is limited by how many eggs they can produce; better camouflaged females have higher fitness.

How are antlers in a deer an adaptive trait?

Males with large antlers are more likely to fight off rival males.

How is skin color as an adaptation to the environment? Predict the approximate skin color of human populations based on their geographic location.

Melanin to darken skin that protects against sun Selection for different melanin concentrations for the different sun intensity Lots of melanin WITH lots of sun Less melanin WITH less sun Natural selection favored best combination depending on environment Lots sun= vitamin D and lots melanin (DARK) Medium sun= vitamin d/b and some melanin(TAN) Less sun= vitamin B and less melanin (LIGHT) Africa= dark, Russia= light

Describe the migration of the different species of Homo out of Africa into the different continents of the world?

Migrated about 100k years ago First moved east, then north and west and east, then north east and southeast

The group of apes does not include __________.

Monkeys

Bipedalism and reduction of body hair in humans is a result of

Natural selection

You observe an animal that has body hair, forward facing eyes, and opposable thumbs and big toes. Based on these traits, what is the smallest group you could safely classify this animal into?

Primate

An alien naturalist expedition to Earth landed in a dense jungle. Here they found a group of animals that had forward-facing eyes and opposable thumbs; the mothers lactated and nursed their young infants. This group of animals belongs to:

Primates

Mutations occur...

Randomly

What factors are thought to responsible evolution of large brain size in humans? How may have this trait been advantageous to early humans?

Rapid increase encephalization(big brain small body) Factors: 1. Homo habilis: extensive use of stone tools (were able to hunt and eat meat) 2. Homo erectus: use of fire (able to cook meat; cooking increases the energy content of food) 3. Homo sapiens: faced great climatic fluctuations (selection favored individuals capable of complex thought) Advantageous: Complex thought, expression, emotion Allowed for better hunters and cooperation Attractive qualities to get mate

Which of the following is TRUE?

Selection pressure (i.e. which individuals gets selected, and how strong the filtering process is) can change with changing environment

Rank the following steps that likely led to the speciation between the chimpanzee lineage and hominin lineage.

Separation of populations in two habitats, Evolution of each population in their own habitats, Reduced interbreeding between the two populations.

Male guppy A is more likely to be found in... less colors and elaborate designs, bland.

Site with lots of predators

The process by which one species splits into multiple species is called ______.

Speciation

Describe how a geographical barrier dividing two populations of a species can lead to the formation of different species?

Speciation: the process by which new species arise from ancestral species Microevolution: evolution within a population over a small time scale • E.g., evolution of peppered moths: increase in frequency of black morphs after the advent of the Industrial Revolution Macroevolution: evolution above the species level, over larger time scales Grand trends and transformations in the history of life • E.g., evolution of mammals, evolution of humans, etc. No dramatic change-chimps don't turn into humans Over time, the two diverging populations become very different from each other The two populations evolve from the new environment selecting

A(n) ___________ is a group of interbreeding populations which are reproductively isolated from other groups.

Species

Explain how human taste buds are an adaptation to the environment.

Sweet and salty helped ancestors get high quality food in uncertain environment — preference=good survival and reproduction Bitter foods meant toxic — distaste=good for survival

Explain the difference between a symptom and an adaptation in the context of disease.

Symptom means from the pathogen and fever made by sickness Adaptation means immune system created the fever to fight off the pathogen

Each separated population can experience different mutation rates, different selection pressures, and different rates of genetic drift, because of which the populations evolve differently.

TRUE

Hominidae is a group consisting of only humans, chimpanzees, bonobos, gorillas, and orangutans.

TRUE

True or False: Early exposure to microbes is associated with lower incidence of food allergies.

TRUE

Two organisms mate and have offspring. How could you test to see if the parents were the same species?

Test to see if the offspring are fertile

Whenever Darwin saw a peacock with its magnificent tail, he would feel sick! Why do you think he felt that way?

The peacock's tail defied all that he had postulated about natural selection and evolution. the peacock's tail did not seem to be adaptive at all. He later realized that it was adaptive (increased fitness) via sexual selection.

Which of the following is NOT necessary for Natural selection to occur?

The population consist of more individuals with the beneficial trait than those with the unfavorable trait

When two populations of the same species become separated, and there is no gene flow between them for approximately 10,000 generations, what is most LIKELY to be TRUE after all this time?

The two groups are genetically very different

Which of the following factors would contribute to speciation after two populations are created by a geographic barrier?

The two populations are exposed to different natural selection pressures

A highway is built through a forest, splitting a deer population into two populations. Which of the following must occur if these two populations are going to evolve into different deer species?

The two populations must become reproductively isolated from each other

Which of the following conditions are necessary for two species to emerge from a common ancestor?

There must be a condition that divides and maintains the ancestral populations as separate populations. There should be no migration of individuals between the populations to allow gene flow. The two populations must become different genetically over time due to the lack of gene flow, and occurrence of evolutionary processes within each population.

How do bacteria acquire the genes to resist certain antibiotics?

Through random mutations OR by taking the genes from dead bacteria OR by taking the genes from bacteria that can share their genes

What adaptations do humans have for tool use?

Thumb metacarpals more complex

Philip Kitcher video: True or false: Human populations can be separated into clearly different groups based on their genetics.

True; but the number of groups where we draw the lines is completely subjective and artificial.

What are vaccines and how do they work?

Types: attenuated-weakened virus of common strain, closely related harmless virus that produces virus protein, rna with info to produce virus protein How: host produces antibodies to recognize virus protein so they'll be ready to fight back later Viruses mutate quickly which causes new strains to come High mutation= HIV, flu Slow mutation= measles Vaccines did not cause autism

What are viruses? Describe their activity in a host cell.

Virus: has specific proteins on surface to specific strain. Activity: proteins latch on to cell and enter nucleus which causes cell to accidentally copy the virus's genetic material also and causes cell to make virus proteins.

Describe the evidence that determines whether fever is a symptom or an adaptation.

When experimenting fever reducing drugs on sicknesses the placebo group always recovers faster because they are allowing the fever to continue so that it will fight off the disease. Results= don't treat a fever bc it is helping

Why or how did early humans evolve from being arboreal lifestyle to terrestrial life?

Why: Evolved in trajectory that environment selects for and common ancestor of chimps How: natural selection favored bipedalism in ancient human ancestor Speciation of two ancestral ape populations resulting in evolution of genes in specific habitats Example: savanna-dwelling population Transitioned into Australopithecus before humans

Antibiotic resistance is...

a trait in bacteria that is genetically determined.

Bacteria reproduce _____.

asexually by binary fission

The evolution of large brains in hominins coincided with three events. These include all of the following EXCEPT...

bipedalism

Repeated use of antibiotics...

creates an environment that selects for antibiotic resistant individuals.

Which of the following is NOT characteristic of primates?

dry noses

Explain the hygiene hypothesis in the context of the immune system.

early exposure to microbe pathogens taught the immune system to respond properly to infection Hygiene causes Insufficient exposure to microbes at early life stages provides insufficient "database" for the immune system to work with

Daniel Fairbanks says that the term "race" does not make biological sense because...

it represents regional ancestry only to a certain point.

What is the trade-off with having large brains?

large head and the brain requires a big amount of energy

What are some fitness trade-offs as a result of the evolution of bipedalism?

narrow hips, lower back problems, hernias, ruptured discs

having the genes for antibiotic resistance makes those bacteria have higher fitness...

only in the presence of the antibiotics.

Which of the following is NOT an adaptation to bipedalism?

opposable big toes

Hominins are...

species that are more closely related to humans than to chimpanzees.

You find a fossil of a hominid hand. It's thumb metacarpel is short and thick. Based on this, you hypothesize that this hominid __________

used tools

Which of the following traits are favorable for bipedalism? 1. Bowl shaped pelvis 2. Short lumbar region of the spine 3. Opposable big toes 4. Short toes 5. Long forearms

1, 2, and 4

Interbreeding

1. Early modern human lineage with eastern Neanderthals 2. Western Neanderthals with Asians and Europeans 3. Denisovans with Asians 4. Denisovans with eastern Neanderthals 5. Mystery hominin with Denisovans

What is the biological species concept definition of a species?

A group of organisms that are able to interbreed successfully in nature. Interbreeding in captivity does not count!

Males a particular bird species have a bright blue crest of feathers on their heads. Females are attracted to males with larger and brighter blue crests, and more females mate with such males. However, the crests also make them conspicuous to predators such as hawks. Which of the following populations is likely to have more males with small pale blue crests and very few males with large bright blue crests?

A population in a habitat that has very few trees, making it easier for hawks to see these birds. In such a habitat, the brightly colored males will be very conspicuous to predators and will be selected against. Birds with small pale crests will be favored by selection because they are less conspicuous to predators.

Which of the following is FALSE about SYNAPOMORPHIES

A synapomorphy is best defined as a trait that is not under selection pressure.

Which of the following is important to prevent antibiotic resistance from developing in a population of bacteria?

Absence of antibiotics in the environment of the bacteria

Humans evolved for endurance running. How was endurance running advantageous to humans? What are the specific traits that help with this?

Advantageous: persistence hunting(out run the prey) Traits: large lunge capacity, skeletal anatomy neck and feet, reduced body hair, sweat glands, bipedalism

Homo sapiens evolved in ________

Africa

The idea of "common descent" implies that...

All closely related organisms descended from a common ancestor

What are autoimmune disorders and allergies, and why are they on the rise in westernized populations?

Allergies: Immune system attacks harmless substances. Mounts immune response against non-pathogens • (pathogen = disease-causing agent) Auto-immune conditions: Immune system attacks body's own tissues Westernized pop: because we have less exposure to pathogens for our immune system to fight off so our immune system gets mistaken and thinks that these harmless non-pathogens are bad.

Did Ardipithecus walk bipedally on the ground or climb trees?

Ardipithecus was adept at both

Why are natural selection and sexual selection considered opposing forces? Explain.

Armaments and ornaments might not work for the environment in other aspects than producing.

What were some benefits of bipedalism to ancestors of humans?

As the environment changed from woodland to savannah, bipedalism was a more efficient mechanism of movement between wooded patches, Standing upright on branches in trees gives greater access to food, Running bipedally is energetically more efficient.

Describe the factors involved in the evolution of antibiotic resistance

Bacteria become exposed to antibiotics from lints and fungi that produce it so bacteria has evolved ways(resistance) to survive that environment. How?they have had many random mutations in different bacteria so they have many mechanisms Example: penicillium mold produces antibiotics penicillin to kill bacteria from competition—-Alexander Fleming discovered 1928

Mutations

Bacteria mutates at high rates and sometimes is beneficial by making them resistant Transferred: vertically=parents, horizontally=one individual to another How: random mutation, pick up from dead bacteria, horizontal, vertical Antibiotics: take full prescription bc first time doesn't kill all of them and they will reproduce so need to keep taking to kill all.

What were some of the traits that are unique to Homo sapiens?

Bipedal, large brains, used tools for food, complex social life, language, communication, expression, emotion, symbols and rituals

________ is a defining characteristic of the human lineage.

Bipedalism

Which of these conditions are always true of populations evolving due to selection? Condition 1: The population must vary in traits that are heritable. Condition 2: Some heritable traits increase reproductive success. Condition 3: Individuals pass on all traits they acquire during their lifetime. Condition 4: Sexual reproduction

Conditions 1 and 2

What are the conditions for sexual selection to occur? How is it different from natural selection? Explain.

Conditions: limited by factors for fitness Different individuals have different reproductive success because of access to mates • Males compete with other males in rivalry for females • Males are attractive to females, so females choose to mate with them For males: finding and keeping mates is most important for fitness For females: survival, nutrition to produce offspring, and offspring survival is most important for fitness Ornaments and armaments—benefits outweigh costs Sexual-producing most offspring Natural-surviving environment

Elaborate traits exist in many animal species because:

Cost of elaborate traits are lower than the benefits of elaborate traits.

What are the costs and benefits associated with sexually selected traits?

Costs: Energetic costs Conspicuous to predators Hindrance while escaping from predators Benefits: Fight off rivals Win many females Depends on environment is cost outweighs benefits

Which of the following belong to the same species?

Dachshund and Great Dane (types of dogs): they can interbreed naturally and produce fertile offspring

Which of the following is a true statement about human populations and genetics?

Different populations of humans differ from each other only with respect to a minor subset of genes

What are "evolutionary legacies" and "maladaptations"?

Evolutionary legacy: A trait that exists because of an evolutionary history —bipedalism Maladaptation: trait that was adaptive in one environment, is now deleterious in a new environment—taste buds

A scientist finds what she thinks is a new species of rodent on a small Pacific island. However, some similar-looking rodents inhabit some nearby islands. She mates the new rodent with the nearby rodents and gets viable but infertile offspring. Can the two groups of rodents be considered to be the same species?

FALSE

Daniel Fairbanks video: Different human populations differ in some phenotypes like hair color and skin color. This is representative of the genetic variation seen between different populations of humans.

FALSE

Fossils of footprints discovered in Laetoli by Mary Leakey's research team led scientists to realize that large brains evolved before bipedalism in the ancestors of humans.

FALSE

In humans, males have longer canine teeth than females.

FALSE

Once one species has split into multiple new species, speciation will not occur again in these species.

FALSE

Philip Kitcher video: There is absolutely no genetic sequence that is more commonly found in one group of humans than any other group of humans.

FALSE

T/f antibiotics can kill viruses

FALSE

True or false: Humans evolved from chimpanzees

FALSE

Males in many bird species have bright colored feather that makes them conspicuous to predators and reduces their survival, yet they posses these traits. Which of the following is NOT true about such traits?

Females will not show a preference for such traits, because they know that the traits will be inherited by the offspring making them vulnerable to predation.

What is the function of a fever during illness

Fever, by elevating body temperature, creates a condition that is unfavorable for the pathogen.

Given what you know about melanin and vitamins in our bodies, which of the following would be important for a dark-skinned person to stay healthy in a northern latitude?

Foods rich in vitamin D

Philip Kitcher video: The amount of genetic variation within groups categorized as different "races" is ________ than the variation between the groups.

GREATER

When two populations of the same species become separated, there should be no __________ between the two populations for them to become genetically very different.

Gene flow