evolution final exam

Identify the description of each type of tool as an Oldowan, Acheulean, or Levallois tool. This type of tool is approximately 400,000 years old and is made from stone. It is a sophisticated broad, flat blade that is very sharp and could have been used for cutting and scraping by Homo heidelbergensis.??? This type of tool is approximately 2.6 million years old and was discovered in Tanzania. It is a primitive tool made from stone and appears to have been used for crushing.???? This type of tool is approximately 1 million years old and is a hand axe made from stone. Tools similar to this one have been found in Africa, Asia, and Europe in conjunction with Homo erectus fossils

-Levallois -Oldowan -Acheulean

Identify the challenges in comparing convergent evolution and parallel evolution.

-Traits that appear to result from convergent evolution may be composed of other structures or traits that share a common ancestry and have independently evolved in parallel. -Convergent evolution may actually be parallel evolution if distantly related species have a common ancestor from which they inherited a regulatory gene controlling their similar traits.

Proteins are made from a combination of 20 different _______________ that can be strung together in any order to make protein chains with different sequences and lengths. These protein chains fold into a variety of shapes such as sheets, cylinders, and other forms because the building blocks of proteins _____________________ The final shape a protein takes on as it folds allows each protein to __________________

-amino acids -vary in their affinities for water -do a precise task

dispersal events:

-ancestral lemur fossils are found in Eastern Africa, and present day lemurs are found only on Madagascar -similar plant fossils appear on either side of the Grand Canyon

Scientists hypothesize that the first major adaptation that led to the evolution of modern humans was the evolution of _______It led to the first major divergence of the hominin lineage from bonobos. Later, australopithecines fossils were first to show that hominins had developed the ability to ________ The most recent physical adaptation that set the Homo sapiens lineage apart from its ancestors was _________

-bipedalism -use primitive stone tools - a large brain

Scientists can infer the diet of an extinct animal by analyzing the __________ of fossilized bones and teeth. The analysis is possible because of the relationship between plants and animals. During photosynthesis, different kinds of plants collect _______________ in different ratios. When an animal consumes a plant, it metabolizes the tissue and assimilates the plant's molecules into its own body. The _________ are integrated into the animal's bones and teeth in ratios that are __________ the ratios found in the consumed plant tissues

-chemical signature -carbon 12 and carbon 13 -carbon isotopes -similar to

the role of the hox genes in development are to....

-determine the timing of the development of body parts in animals with bilateral symmetry -direct the head to toe patterning of body parts in animals with bilateral symmetry

characteristics of DNA

-double stranded helical molecule that uses thymine in one of its nucleotides -stores the directions for producing all the cells part and is the genetic material in most organisms

vicariance events:

-elephant bird fossils are found only on madagascar -the separation of Gondwana from Laurasia resulted in the speciation of modern day parrots

Today's doctors are taking an ______ approach to understanding the genetics behind the various conditions that affect human health. Instead of treating all patients similarly, doctors are considering genetic _______ and genetic history to customize the prevention, management, and treatment of disorders.

-evolutionary -variation

When deceased organisms leave behind _____________ scientists can construct phylogenies based on morphology. The first phylogenies of________________ arose through the study of fossils, though they have since been revised with the development of genetic technologies. _________________ requires a very specific set of environmental conditions, such as an anaerobic environment, so most known fossils are of ancient macroscopic organisms. Scientists can use ________________ to construct phylogenies for younger species, such as humans, and microscopic organisms, such as viruses. With one method, scientists use short, noncoding segments of DNA called _______________to compare relatedness among individuals and populations.

-fossilized remains, - tetrapods -Fossilization -genetic material -microsatellites

Understanding population genetics can also be helpful in medicine. When individuals succumb to a lethal genetic disease before reproducing, the _________ of the defective allele generally decreases in the population. But some harmful alleles can become more common if the ________ genotype provides a benefit, such as protection from a different harmful condition. Deleterious alleles can also be amplified with the genetic drift that occurs more readily in small populations, as with the _______ effect

-frequency -heterozygous -founder

Genome size has evolved differently in bacteria and eukaryotes. The genomes of bacteria are small compared to those of eukaryotes and are made up mostly of ________________ Across species of bacteria, genome size is _____________to gene number. In eukaryotic species, the genome contains a _____ amount of non‑coding DNA, and genome size does not correspond to gene number or complexity of the organism. The genomes of both bacteria and eukaryotes can increase in size through ______________ In addition, the bacterial genome can get larger through ___________________ The genome size of both bacteria and eukaryotes can decrease with _____________ Also, in bacteria,____________ that no longer code for proteins or RNA are frequently deleted from the genome.

-functional genes. -proportional -large -gene duplication. -horizontal gene transfer. -deletion. - pseudogenes

what events that occur in meiosis increase genetic diversity in sex cells?

-genetic recombination -independent assortment

Scientists hypothesize that the Cambrian Explosion of animals was caused by many factors. The spark for adaptive radiation may have been the occurrence of changes in the __________ that allowed for the evolution of new body plans. Besides these ___________ factors, changes in the __________contributed to diversification.__________ led to an increase in sea level, which created new habitats for marine animals and deposited ____________ in the ocean that contributed to their growth. A concurrent rise in __________ levels brought the appearance of shells and other hardened defenses and weapons.__________ concentration also increased in oceans, providing cells the fuel needed to power bodies for motion and larger growth. Animals that could burrow into the ocean floor created new ________, and larger animals began to eat smaller animals, which increased the complexity of ____________. Together, all these factors both triggered and perpetuated the conditions necessary for the creation and filling of new ecological niches.

-genetic toolkit -developmental -environment -tetonic activity -phosphates -calcium -oxygen -habitats -food webs

what evidence refutes the thrifty genotype hypothesis

-hunter gatherer populations experienced fewer periods of famine than subsistence farmers -scientists have not found evidence of natural selection acting on genes that cause metabolic disease

Some inherited conditions, such as ______ follow the simple rules of __________ genetics. other genes influence disease in a more complex fashion. for example, For example, certain variants of BRCA1 increase the risk of some cancers.

-huntingtons -menedlian -some cancers.

Human health has been affected by pathogens and cancer for thousands of years. Both pathogens, such as bacteria and viruses, and cancer weaken the immune system and invade cells and tissue within the human body, resulting in ___________ There are many similarities in the mechanisms by which both pathogens and cancer work in the body. Both cancer and pathogens continue to evolve after they become established in the body. The cancer cells and pathogens evolve in response to the specific conditions inside their __________ Pathogens have an additional requirement for survival. Pathogens must transmit from person to person. Transmission typically occurs through ____________ Pathogens must replicate and evolve for survival but cannot become too virulent or the host will die before disease transmission can occur. Cancer cells _______ transmitted from person to person, so the survival of cancer cells depends on _____________

-illness and death -host -body fluid -are not -proliferation

The hypothesis of ecological character displacement proposes a possible mechanism to explain how divergence occurs. According to this hypothesis, if two species compete for a resource, such as a specific type of food, ________________________________________ A few individuals in one or both of the species may be able to exploit an alternative resource that cannot be used by most of the individuals in either species. Because these few use a different resource than the rest of their species, they will ________________________________ Eventually, the two species will become less alike in the way they use the resource through ____________________ selection.

-individuals in both species will face intense competition for the resource -face less competition and have more success reproducing -directional

Hox genes are components of highly conserved regulatory networks that bilaterally symmetrical animals ___________________________Humans, mice, fruit flies, and box turtles all have heads without appendages in part because their Hox genes_________________ along each animal's chromosomes, ____________________________ in all of them. When scientists silence Hox genes in fruit fly embryos and insert mouse Hox genes in their place, the flies _____________________

-inherited from a common ancestor. -, which occur in the same order -determine where body parts develop -continue developing as flies.

Eukaryotic DNA is arranged in ___________________________________________ DNA in bacteria and archaea is arranged in ____________________________________________ The most common way in which eukaryotes produce offspring is by ______________________________ When bacteria and archaea produce offspring, they _________________________________ Bacteria and archaea can also _____________________ through a temporary pilus.

-linear chromosomes wrapped around histone proteins in the cell nucleus -a single ring shaped chromosome that floats free in the cell -combining half their DNA with that of another individual -copy their DNA and put one copy in each caught cell when they divide -transfer DNA to neighboring cells

what uses have scientists found for linkage disequilibrium?

-linkage disequilibrium allows for scientists to offer inexpensive tests for inherited risks for certain diseases -linkage disequilibrium can show a scientists a genes location if known genetic markers correlate with a phenotype -the level of linkage disequilibrium helps scientists determine how long an allele has been in existence

characteristic of protein

-makes up many structural and operational molecules in an organism such as hemoglobin and enzymes -is composed of chains of amino acids that fold in 3-D shapes

Specific diseases have also molded the human genome. For example, in geographical areas where mosquitoes commonly carry the pathogen for ___________ mutations that confer resistance to the disease spread at a high rate through human populations. As a result, these defensive alleles appear at___________ frequency than in areas where the disease is less common.

-malaria - a higher

Doctors might also use genetics to identify a _________that has optimal efficacy and minimal side effects for a patient. This tool aids in predicting the variability of responses to specific chemicals that occur under the influence of ________ genes.

-medication -polymorphic

Evolutionary biologists use morphological characters to create species trees. Similarly, scientists use ________ characters to create gene trees. More specifically, the characters of a gene tree are the ________ of a gene's nucleotide sequence. When a _________ event occurs, a new allele arises in the gene tree. This divergence is represented by a _________, and each of the various alleles in the sample group are represented by a _____ with one common ancestral allele at the ______ A constructed gene history does not always reflect the history of the species in which the gene is embedded. With ____________________________ different alleles pass into newly isolated populations by chance and may be randomly lost over time. Discrepancy between gene and species trees also occurs with ____________________, or the introduction of new genes into a species through hybridization.

-molecular -bases -mutation -branch -tip, -root. -incomplete lineage sorting, -introgression

________ or random error during DNA replication, is another evolutionary mechanism that affects the gray wolf's evolution. Random errors may result in beneficial, neutral, or harmful phenotypes in individuals. Today's gray wolf has evolved ________ over time, as expected because of the complexity of its genetic material and its reliance on sexual reproduction.

-mutation -slowly

The Breeder's equation states that the response to selection, R, is a function of the selection differential, S, and _________________ As the selection differential __________, R becomes larger. In addition, if heritability is ___ then regardless of how large S is, ___________

-narrow‐sense heritability, h2. -becomes larger -0 -there will be no response to selection

Mutations produce random genetic changes in both cetaceans, such as whales, and viruses, such as influenza. Populations of both types of organisms evolve when some mutations produce beneficial traits that are favored by ____________ in the current environment or when traits are lost by chance through __________ In addition, viruses sometimes reassort their genes. Reassortment happens when two viruses invade a cell and produce offspring ___________ from both viruses. Evolution takes place more quickly in viruses than in cetaceans because viruses _________ than cetaceans.

-natural selection -genetic drift -that contain some genes -reproduce faster

One mechanism for the biological evolution of today's gray wolf is _________ a process through which organisms with favorable traits are more likely to reproduce than competitors. This nonrandom mechanism works only if ______ exist in the population.

-natural selection -genetic variations

A change in habitat from rainforest to woody grassland, making food ________ may have been a selective pressure favoring larger brains in early hominins. Larger brains require_________ and selection favored adaptations that helped provide them, such as an upright posture and using tools to dig and butcher. During the Pleistocene glaciations, selection favored adaptations for survival in harsh, variable environments, and ________ selection for larger brains became more frequent in the Homo genus than it had been in Australopithecines. Larger brains provided more selective pressure, and ___________ first appeared in the Homo genus. Indications of complex language use, such as ceremonial art, trade over long distances, and local experimentation with tool design, appeared only after brains reached the size of _______ Computer modeling suggests that the strongest selective pressures driving the evolution of intelligence in hominins have likely been ___________ interactions, highlighting the value of skills such as tool making and use.

-patchy and seasonal -more energy and nutrients -directional selection -more sophisticated toolmaking and hunting -homosapiens -ecological rather than social

define the unique characteristics antigenic shift:

-produces viral variants by genetic reassortment -forms hybrid viruses from different viral strains -causes pandemic due to radical changes in the virus

define the unique characteristics antigenic drift:

-produces viral variants from accumulated mutations -occurs during each new infection

descriptions of broad sense heritability:

-proportion of phenotypic variance due to total genetic variance -includes genetic variance due to epistasis, dominance, and additive effects -is a useful method to measure genetic versus environmental effects on phenotypic variance

Scientists apply their knowledge of evolution to improve vaccines. Instead of delivering a dead virus or its ________ some vaccines induce an immune response by delivering a live virus. Scientists must first weaken the virus using the process of ________ so that no serious illness results. To produce a live polio vaccine, for instance, researchers force the virus to evolve in the cells of a _______ species in which it does not naturally replicate. The virus manages to survive, mutating as it slowly replicates. As the virus adapts to these cells, it becomes increasingly _______ able to infect human cells. However, injected in the human body, it can still elicit a strong immune response.

-protein fragments -attenuation -primate -less

statement that describe narrow sense heritability h^2

-quantifies only a portion of the genetic component of phenotypic variation -calculated by dividing the additive component of genetic variation by phenotypic variation -quantifies the most predictable component of heritability

____________genetics is the study of evolutionary mechanisms of continuous variation in phenotypic traits. Continuous, or quantitative, traits are frequently __________ traits that depend on alleles at multiple loci. Additive effects of alleles or nonadditive interactions among alleles, also known as ________ may influence trait expression. Also, the _________of alleles in response to the environment may affect the degree of their expression.

-quantitative -polygenic -epistasis -plasticity

define the characteristic with both antigenic drift and antigenic shift

-requires genetic variation -leads to viral evasion of antibodies -leads to evolution of the human immune response

The genes of human pathogens are shaped primarily by ________ in the environment of the human body. In turn, pathogens shape the human _________ This evolutionary arms race has taken place over millions of years. For instance, viruses must interact with host ________ to be able to invade a host cell and replicate. When _________ occurs in these host macromolecules, a virus may respond to the selective pressure by evolving in kind. One researcher concluded that selective pressures due to viruses have caused ________ of the proteins in the hominin lineage to have altered amino acids.

-selective pressures -genome -proteins -random mutation -1/3

characteristic of RNA

-single stranded molecule that uses uracil in one of its nucleotides -functions during gene expression as the working code, construction platform, and translator

identify evidence you would use to refute the statement "all multicellular life evolved along a single lineage"

-some fossilized multicellular organisms are not clearly related to one of the main lineage of extant life -the lineage of the oldest recognizable fossils of multicellular organisms disappeared from the fossil record -multicellularity among species of bacteria versus eukaryotes functions differently

parallel evolution examples:

-stickleback fish have reduced armor in each separate population that has low predator pressure -each cave fish population independently evolved paler skin than its relatives in nearby surface lakes

The first animals with four legs appeared at least 370 million years ago. All four‑limbed animals are called ________.By 280 million years ago, the four‑legged animals that had temporal fenestrae in the skull and were the dominant lineage were called _________ One branch of this dominant lineage further evolved into ________ about 160 million years ago.

-tetrapods -synapsids -mammals

examples of homology:

-the bones in bat wings that look like elongated versions of the finger bones in human hands -hox genes control development in insect and mice

Most scientists agree that ________ was the driver for the evolution of bipedalism in early hominins. Toward the end of the Miocene, as the climate became ________ dense African forests changed to ________.One hypothesis of bipedalism suggests that bipedalism allowed hominins to _______ more efficiently. Because trees were more scattered, early hominins could save energy by walking from tree to tree and reaching for food instead of climbing trees. Another hypothesis of bipedalism suggests that walking erect allowed hominins to _______ when moving in open habitats such as grasslands. By walking upright, they were able to reduce the amount of surface area being exposed to the sun.

-the changing environment -drier -grasslands -forage -stay cooler

how can the human body shape the evolution of pathogens?

-the human immune system exerts pressures that cause pathogens to improve upon use of the host's resources

statements that describe broad-sense hertitability

-the portion of phenotypic variation not associated with environmental factors -a measure of the relative importance of genetic factors to the phenotypic variation of a trait

descriptions of narrow sense heritability

-the proportion of phenotypic variance due to only the additive effects of alleles -describes how closely offspring resembles their parents -can be estimated to predict evolution through natural selection

examples of convergent evolution:

-the streamlined body forms of whales and fish reduce the energy needed to move through water -the broad, flat shape of bird wings and insect wings enables flight

Extinction is a normal process. __________ become extinct. Historically, global extinction rates are _________________ Some of the _________ rates of extinction in the past were related to natural, dramatic changes in climate. Although the previous statements are true, humans create unique challenges for other species. Resource extraction and agriculture have resulted in ____________ In addition, humans have caused the extinction or near extinction of species through ______________ Humans are also altering global climate and ocean acidity through the burning of fossil fuels. These pressures have led to an extinction rate that __________the normal background rate of extinction.

-the vast majority of species -variable, ranging from low to very high over time -highest -the loss of large areas of habitat -overhunting and overfishing -far exceeds

Vertebrate eyes have light‑sensing structures that face away from the light and a blind spot caused by the placement of the optic nerve. Complex adaptations such as these, which seem oddly designed for the function they serve, arise ___________________________These inefficient adaptations can only persist if they _______________________________ individuals that possess them.

-through natural selection on existing variation. -provide some immediate fitness benefit for

Scientists are also using their knowledge of evolution to create _______ vaccine. Instead of formulating a new vaccine every season, scientists are trying to develop one that stimulates the production of ________ that would target all strains of the virus. Standard vaccine antibodies bind to the tip of the _________ stalk, which continually mutates. However, the new antibodies would bind to the _______ which is nearly identical across all strains and not likely to mutate without causing harm to the virus.

-universal influenza -one type of antibody -hemagglutinin -base

Which scenarios describe evolutionary benefits of a nervous system?

A jellyfish contracts its ring of muscle to swim toward the light at the ocean's surface. A leopard tracks the scent of a gazelle herd, then sees a straggler in the distance to target.

describes how a biased operational sex ratio (OSR) can generate strong sexual selection.

An OSR can create intense competition between members of the more abundant sex.

identify the branch of life that each passage describes: Scientists propose that these organisms were Earth's earliest inhabitants. They were likely responsible for the high concentration of methane in Earth's early atmosphere.

Archaea

How does the fossil record provide support for Darwin's theory of evolution?

Fossils make clear that species arise from other species and radiate over time. Fossils indicate the periods when species existed and when they went extinct.

Match each naturalist with his or her contribution to scientific understanding of the fossil record and extinction. This naturalist compared elephant fossils to the skeletons of living elephants from Africa and India, which helped establish that many fossils were remains of extinct species.

Georges Cuvier

Which statement describes how evolution through natural selection works?

Individuals with successful phenotypes have an increased chance of producing viable offspring, which changes the population's genetic structure between generations.

Why is anthropomorphism a dangerous thought pattern in the study of animal behavior?

Many effective animal responses are merely inherited along with the nervous systems that have evolved. Scientists lose objectivity when the evolution of animal behavior is viewed in light of human traits. A human attribute, such as intent, is neither likely nor necessary for the actions that animals take.

Match each naturalist with his or her contribution to scientific understanding of the fossil record and extinction. This naturalist recognized that triangular rocks found at the top of certain mountains were fossils of teeth from sharks, which pioneered the field of stratigraphy.

Nicolaus Steno

What is the most likely explanation for all extant copies of a gene coalescing?

One gene copy out of the multitude of copies that existed in the past gave rise to all the extant copies.

What hypothesis concerning evolution did Jean‑Baptiste Lamarck propose based on his observations of anatomical similarities between species?

Organisms acquire adaptations during their lifetimes and pass the adaptations to their offspring.

the hypotheses for why women go into menopause.

Reduced fertility provides a selective advantage by allowing women to invest their resources in raising their existing children. Older women increase their genetic contribution to future generations by helping their grandchildren instead of birthing their own.

Why does natural selection have little effect on senescence?

Reproduction generally occurs before senescence genes begin to produce harmful effects on fitness.

How is the neutral theory of evolution used to deduce the timing of evolutionary events and the history of natural selection?

Scientists use a steady rate of mutation accumulation to date events and apply the theory as a null hypothesis for natural selection.

Which observations are examples of homologies?

The pharyngeal arches found in all vertebrate embryos develop into gill supports in fish and throat structures in mammals. The bones that support the wings of birds, pterosaurs, and bats are arranged in the same order in each animal. The Pax6 gene in vertebrates and the eyeless gene in flies have similar sequences, and both regulate embryonic eye development

variables that lead to antagonistic coevolution between sexes in a species.

The sexual strategy of one sex lowers the fitness of the other sex. A characteristic confers a fitness benefit to one sex and a fitness cost to the other.

what happens to a population when biological evolution takes place?

a change takes place in the genetic traits passed from one generation the population to the next

What circumstance might give rise to a novel trait?

a deletion mutation alters the timing of the activation of regulatory network

why does natural selection favor evolution of new virus strains?

a new virus strain may evade a host's immune defenses in ways existing viruses cannot

why does natural selection favor the evolution of new virus strains?

a new virus strain may evade a host's immune defenses in ways existing viruses cannot

what appear to be disease may actually be ______

adaptions

which observations provide evidence that evolution has occurred?

an antibiotic that initially kills most of the bacteria in a population loses its effectiveness after several bacterial generations the protein sequence of human insulin has more similarities with chimpanzee insulin than with lizard insulin fossil remains indicate that the ancestors of modern horses had toed feet that transitioned over time into hooves

What are the primary factors that provoke an evolutionary arms race?

antagonistic interactions between participants selective pressure to respond to evolution in other participants

identify the branch of life that each passage describes: These organisms diverged from a simple ancestor more than 3.5 billion years ago. They were likely responsible for the dramatic rise in the concentration of free oxygen in the atmosphere roughly 2.4 billion years ago.

bacteria

sympatric speciation

caused by gametic, behavioral, and temporal mechanisms occurs among subpopulations that inhabit the same geographic area

What factors can affect the behavior of organisms that do not have a nervous system?

chemical signaling light and touch

identify the mechanism in each scenario that led to adaptive radiation: Over fifteen million years ago, marsupials were the only mammals on the island of Australia. Since then, marsupials have radiated into over 200 species today, from the wombat to the Tasmanian wolf

colonization

identify the mechanism in each scenario that led to adaptive radiation: The end-Permian extinction, which occurred over 250 million years ago, killed off approximately 70% of Earth's terrestrial vertebrate species and was followed by the rise of both mammals and dinosaurs

competitor or predator extinction

some traits increase ________ at the cost of increasing vulnerability to disease

disease

allopatric and sympatric speciation

diverging subpopulations cannot successfully interbreed caused by isolating barriers

identify the mechanism in each scenario that led to adaptive radiation: After the expansion of grasslands in North America during the Miocene epoch, horses radiated quickly into a range of morphologies, including the number and arrangement of teeth, suitable for grazing on rough vegetation.

environmental change

identify the branch of life that each passage describes: These organisms were the most recent to diverge roughly 1.6 billion years ago. They were the largest organisms at the time and contained internal membrane-bound components.

eukarya

determine if its phenotypic plasticity or evolution in a phenotypes plasticity: The fur of snowshoe hares is brown in summer and white in winter, but populations in warming areas have begun to retain their brown fur.

evolution in a phenotypes plasticity

a species ______ puts constraints on cute natural selection

evolutionary history

why does homoplasy in hominins make it challenging to categorize hominid fossils?

homoplasies among hominid lineages can make a hominid fossil appear to be closely related to several known species

select the questions that can explored through the principles of biological evolution

how do new species arise in novel environments? how can viruses such as influenza be difficult to fight? how did cetaceans transition from terrestrial to aquatic environments?

identify the mechanism in each scenario that led to adaptive radiation: Some evolutionary biologists have proposed that the evolution of the sticky toe pad of Caribbean anole lizards has allowed the species to interact with its environment in a novel way, thus facilitating access to new resources.

key innovation

allopatric speciation

occurs through geographic isolation caused by.a physical barrier that prevents mating between sub-populations

_____ evolve faster than their hosts

pathogens

select the examples of evolution via natural selection from the list of scenarios

penguins with heritable traits the improve swimming at better able to survive and reproduce bacteria that are resistant to antibiotics increase in frequency in a population

determine if its phenotypic plasticity or evolution in a phenotypes plasticity: The leaves growing in shade on a sugar maple tree are larger than the leaves growing in full sun on the same tree.

phenotypic plasticity

determine if its phenotypic plasticity or evolution in a phenotypes plasticity: The skin of a green anole lizard shifts from green to brown when the anole moves from a leaf to the bark of a tree.

phenotypic plasticity

What environmental condition did Rosemary and Peter Grant determine is responsible for forcing medium ground finches to become seed specialists on Daphne Major Island in the Galapagos Islands?

prolonged drought during the dry season

natural selection is _____ than environmental change

slower

definition of genetic drift:

the change in allele frequencies over generations resulting from random events

the definition of speciation.

the division of a species characterized by a lack of gene flow between the two new species

why is revaccination required every time a new seasonal influenza strain arises?

the immunity acquired for one seasonal influenza strain does not protect against new strain surface proteins

what do the rate of origination and extinction of species tell scientist about macroevolutionary change?

the rate indicate patterns in biodiversity over time

which scenario describes the process of introgression?

two lizard species sometimes interbreed successfully, exchanging alleles between the species