biology 1020 exam 1 study guide
describe and give an example of F2 fitness
(postzygotic) even if hybrids can reproduce, their offspring may be unable to reproduce. ex.) some mules may be fertile, but if they reproduce, their offspring probably will be sterile.
describe and give an example of hybrid sterility
(postzygotic) the hybrid zygote may develop into a sterile adult, meaning it won't be able to reproduce. ex.) mules can live through reproduction between a horse and a donkey, but are sterile as adults.
describe and give an example of zygotic mortality
(postzygotic) the hybrid zygote may not be viable, so it dies. a zygote with 2 different chromosome sets may fail to go through mitosis properly, or the developing embryo may receive incompatible instructions from the maternal and paternal genes, so that it cannot continue to exist. ex.) i don't really have an example... it dies.
describe and give an example of gamete isolation
(prezygotic) even if the gametes of two different species meet, they may not fuse to become a zygote. ex.) the egg of some animals has receptors for only
describe and give an example of behavioral isolation
(prezygotic) many animal species have courtship patterns that allow males and females to recognize one another. ex.) the birds with the "funky dance"
describe and give an example of temporal isolation
(prezygotic) two species can live in the same locale, but if they reproduce at different times of the year, they do not attempt to mate. ex.) animals that reproduce in spring don't mate with animals of the same species that reproduce during the fall.
describe and give an example of mechanical isolation
(prezygotic) when animal genitalia or plant floral structures are incompatible, reproduction cannot occur. ex.) now have you ever seen a horse try to reproduce with a turtle? exactly.
describe and give an example of habitat isolation
(prezygotic) when two species occupy different habitats, even within the same geographic range, they're less likely to meet and attempt to reproduce. ex.) two types of bugs that live in the same region may not reproduce because one lives in the soil and the other lives on the surface of water
for natural selection to occur, what 4 steps must occur?
1. The members of a population have heritable variations2. The population produces more offspring than the resources of an environment can support3. The individual that have favorable traits survive and reproduce to a greater extent than those that lack these traits4. Over time, the population of the favorable trait increases in the population, and the population becomes adapted to the environment
what was the cause of the initial 5 mass extinction events?
1. continental drift 2. meteor impacts 3. climate change 4. plate tectonics 5. volcanic erruptions
why are adaptations not perfect?
1. evolution doesn't start from scratch. 2. as adaptations are evolving in a species, the environment may also be changing.
what 5 conditions must be met for the Hardy Weinberg equilibrium?
1. no mutations 2. no gene flow 3. random mating 4. no genetic drift 5. natural selection doesn't occur
how is variation in a population maintained, in spite of selection constantly working to reduce it?
1. the forces that promote variation are always at work (mutations, recombination, fertilization) 2. gene flow might be occurring between 2 populations
what are the 8 characteristics of life?
1. use energy 2. respond to the environment 3. maintain homeostasis 4. pass DNA through offspring 5. reproduce 6. multicelluar 7. evolved from other living things 8. highly organized
in what type of environment is being heterozygous in regards to the sickle-cell trait an advantage? A.) an environment that has malaria B.) an environment that is malaria-free C.) an environment that is cold and rainy D.) an environment that is degraded
A.) an environment that has malaria
when the gametes of each parent organism doesn't fuse, __________ isolation occurred A.) gamete B.) behavioral C.) zygote D.) F2 fitness
A.) gamete
which of the following refers to the movement of alleles among populations by migration of breeding individuals A.) gene flow B.) bottleneck effect C.) genetic mutation D.) founder effect
A.) gene flow
the wing of a penguin and the wing of an eagle are A.) homologous structures B.) analogous structures C.) identical structures D.) vestigial structures E.) not comparable in any way
A.) homologous structures
which of the following is NOT a component of the biological species concept? A.) organisms of the same species look the same B.) organisms of the same species can interbreed C.) organisms of the same species have a shared gene pool D.) organisms of different species must be reproductively isolated
A.) organisms of the same species look the same
sympatric speciation occurs more commonly in which types of organisms? A.) plants B.) humans C.) birds D.) fish E.) insects
A.) plants
_________ is the organisms of the same species in a particular area A.) population B.) community C.) ecosystem D.) biome E.) biosphere
A.) population
swiss starlings have adapted to lay 4-5 eggs. if they lay less than 4 or more than 5, the mortality rate increases. which of the following selection mechanisms does this demonstrate? A.) stabilizing B.) directional C.) disruptive
A.) stabilizing
what is energy? A.) the capacity to do work B.) all chemical reactions in a living cell C.) maintaining a relatively stable constant internal condition
A.) the capacity to do work
the primary goal of the HMS Beagles voyage was to expand the navy's knowledge of natural resources in South America A.) true B.) false
A.) true
which of the following is considered a postzygotic isolating mechanism? A.) zygote mortality B.) gamete isolation C.) habitat isolation D.) mechanical isolation
A.) zygote mortality
The beaks of birds are well suited to the type of food they eat. This result arises from A.) organisms changing so that they can do things more efficiently B.) adaptations that occur as part of natural selection leading to a closer and closer fit between organisms and their environment C.) birds eating only what their beaks are well suited to eat D.) adaptations only allowing those organisms that are well suited to a food source to feed on it
B.) adaptations that occur as part of natural selection leading to a closer and closer fit between organisms and their environment
climate change can be attributed to the increased release of what element? A.) oxygen B.) carbon C.) hydrogen D.) nitrogen
B.) carbon
which of the following represents the lowest level of biological organization that is still considered living? A.) tissue B.) cells C.) atoms D.) molecules E.) populations
B.) cells
fossils that serve as transitional links allow scientists to A.) determine why evolutionary changes occur B.) deduce the order in which various groups of animals arose C.) determine how prehistoric animals interacted with each other D.) relate climate change to evolutionary trends
B.) deduce the order in which various groups of animals arose
which of the following results in polymorphism A.) stabilizing selection B.) disruptive selection C.) directional selection
B.) disruptive selection
decrease in genetic diversity makes populations more likely to withstand environmental stress and less susceptible to extinction A.) true B.) false
B.) false
dominance causes and allele to become more common A.) true B.) false
B.) false
true or false: adaptations forced by natural selection will always produce traits perfectly adapted to their environment A.) true B.) false
B.) false
allopatric, but not sympatric, speciation requires A.) reproductive isolation B.) geographic isolation C.) spontaneous differences between males and females D.) prior hybridization E.) a rapid rate of mutation
B.) geographic isolation
the 6th mass extinction event is primarily due to A.) plate tectonics B.) human impact C.) continental drift D.) meteorite impact
B.) human impact
this type of variable is what you (or the experimenter) manipulates A.) controlled B.) independent C.) dependent
B.) independent
this scientist proposed the law of use and disuse A.) darwin B.) lamarck C.) hutton D.) lyell
B.) lamarck
macroevolution is the term that applies to which of the following? A.) changes of any scale within large organisms B.) large-scale changes over a long period of time C.) any evolution at any scale D.) small-scale changes over a short period of time E.) small-scale changes over a long period of time
B.) large-scale changes over a long period of time
in the process of natural selection, individuals that are most fit are the ones that are A.) most likely to survive B.) most likely to reproduce C.) most likely to migrate D.) most likely to mutate E.) most likely to be physically fit
B.) most likely to reproduce
although Lamarck hypothesized that adaptations to the environment did occur, he also believed that A.) mass extinctions did not occur B.) offspring inherited characteristics that were acquired by their parents during their lifetime C.) similar organisms do not share common ancestors D.) humans descended from apes E.) natural selection was the source of all diversity
B.) offspring inherited characteristics that were acquired by their parents during their lifetime
what is metabolism? A.) the capacity to do work B.) set of chemical reactions that occur in living organisms to maintain life C.) maintaining relatively constant internal conditions D.) the structural and function unit of all living things
B.) set of chemical reactions that occur in living organisms to maintain life
select the statement(s) that is (are) true in regards to binomial nomenclature A.) both names are underlines B.) species is italicized C.) both named capitalized D.) genus is the first name and species is the second name
B.) species is italicized & C.) genus is the first name and species is the second name
two species live in the same locale, but reproduce at different times. this is an example of A.) habitat isolation B.) temporal isolation C.) behavioral isolation D.) mechanical isolation E.) gamete isolation
B.) temporal isolation
which of the following is NOT one of the 4 principles of natural selection A.) over time, the population of the favorable trait increases, and the population becomes adapted to the environment B.) the population produces less offspring than the resources of an environment can support C.) members of a population have heritable variations D.) the individuals that have favorable traits survive and reproduce to a greater extent than those that lack these traits
B.) the population produces less offspring than the resources of an environment can support
tortoises in the galapagos possessed neck lengths unique to each island. neck lengths appeared to be an adaptation to which selective agent? A.) ease in finding pools of drinking water B.) type of vegetation available to eat C.) reproductive barriers used to produce offspring D.) defense against predators E.) male competition for females
B.) type of vegetation available to eat
a zygote fails to undergo mitosis because of a mismatch in the number of chromosomes. this is an example of A.) hybrid sterility B.) zygote mortality C.) F2 isolation D.) temporal isolation E.) mechanical isolation
B.) zygote mortality
blue-footed boobies go through an elaborate courtship dance to find a mate. which of the following types of isolation does this demonstrate? A.) temporal B.) mechanical C.) behavioral D.) habitat E.) gamete
C.) behavioral
The smallest unit of life is a(n) A.) tissue B.) organ C.) cell D.) species E.) organism
C.) cell
The __________ variable is the variable that is kept the same during the experiment. A.) dependent B.) independent C.) controlled
C.) controlled
__________ selection is when 2 or more extreme 2 or more extreme phenotypes are favored over any intermediate phenotype A.) directional B.) stabilizing C.) disruptive
C.) disruptive
a small, reproductively isolated population called the dunkers was established by 27 families that came to the US from germany 200 years ago. the frequencies of blood group alleles in this population differ significantly from those in the general US population. this is an example of A.) negative assortative mating B.) natural selection C.) founder effect D.) bottleneck effect
C.) founder effect
the formation of new and distinct species in the course of evolution is A.) macroevolution B.) microevolution C.) speciation D.) natural selection
C.) speciation
reticulitermes hageni mate between march and may. reticulitermes virginicus mate in the fall and winter. which type of isolation is this? A.) mechanical B.) gamete C.) temporal D.) habitat E.) behavioral
C.) temporal
human influence can be associated with which of the following challenges facing science? A.) loss of biodiversity B.) climate change C.) emerging diseases D.) all of the above
D.) all of the above
the processes in which two smaller molecules are bonded together to form a larger molecule is known as A.) homeostasis B.) catabolism C.) metabolism D.) anabolism
D.) anabolism
which of the following is NOT a characteristic of all living things? A.) assimilate and use energy B.) maintain homeostasis C.) evolve from other living things D.) composed of more than 1 cell
D.) composed of more than 1 cell
finches that inhabited the galapagos islands demonstrated differences in their beaks. what was the cause of these differences? A.) different water sources B.) competition for living area C.) predation D.) food source
D.) food source
sickle cell disease is an example of A.) homozygous advantage B.) adaptive radiation C.) gene flow D.) heterozygous advantage E.) founder effect
D.) heterozygous advantage
which answer choice lists the steps of the scientific method in the correct order? A.) hypothesis, observation, experiment, conclusion, publication B.) publication, conclusion, hypothesis, experiment, observation C.) observation, experiment, hypothesis, conclusion, publication D.) observation, hypothesis, experiment, conclusion, publication
D.) observation, hypothesis, experiment, conclusion, publication
which of the following is NOT an example of natural selection? A.) insect population exposed to pesticides become resistant to the chemicals B.) plant species that produce fragrances to attract pollinators produce more offspring C.) rabbits that sprint quickly are more likely to escape predation D.) on a tree, leaves that grow in the shade are larger than those that grow in the sun
D.) on a tree, leaves that grow in the shade are larger than those that grow in the sun
which of the following would be a biotic factor that can influence natural selection? A.) temperature B.) living area C.) water D.) predation
D.) predation
which of the following is not one of the conditions required for a Hardy-Weinberg equilibrium? A.) natural selection must not occur B.) assortative mating must not occur C.) mutations must not occur D.) random mating must not occur
D.) random mating must not occur
microevolution is the term that applies to which of the following? A.) small-scale changes over a long period of time B.) large-scale changes over a long period of time C.) changes of any scale within microorganisms D.) small-scale changes over a short period of time
D.) small-scale changes over a short period of time
all of the genes and all of their associated alleles within a population represent the population's A.) gene jacuzzi B.) genotype C.) genome D.) gene flow E.) gene pool
E.) gene pool
how have diseases like SARS or zika become emerging diseases?
SARS emerged because people in china began eating a type of exotic cat which carried the virus. zika is carried by mosquito bites.
define mutations
a change made in the nucleotide sequence of DNA. such changes may be due to a replication error or the influence of external sources called mutagens. these generate variation in the gene pool of a population
describe an ecosystem
a community of living organisms along with their physical environment; characterized by a flow of energy and a cycling of inorganic nutrients.
describe a population
a group of individuals of the same species occupying a given location at the same time.
describe an organ system
a group of related organs working together.
describe a tissue
a group of similar cells combined to perform a common function.
define genetic drift
a mechanism of evolution due to random changes in the allele frequencies of a gene pool; more likely to occur in small populations or when only a few individuals of a large population reproduce
what is sympatric speciation?
a population develops into two or more reproductively isolated groups without prior geographic isolation.
what is allopatric speciation?
a speciation model based on geographic isolation of population
what is convergent evolution?
acquisition of the same or similar traits in distantly related lines of descent. ex.) similar wings or beaks
define sexual selection
adaptive changes in males and females of a species often due to male competition and female selectivity, leading to increased fitness.
what is metabolism? (give an example of a metabolic reaction)
all the chemical reactions that occur in a cell. ex.) catabolic reactions (break down larger molecules into smaller molecules); anabolic reactions (build up smaller molecules into larger molecules)
describe a community
all the populations in a particular locale.
what is a dominant allele?
an allele that exerts its phenotypic effect in the heterozygote. it masks the expression of the recessive allele.
what is a recessive allele?
an allele that exerts its phenotypic effect only in the homozygote. its expression is masked by a dominant allele.
what is an allele?
an alternative form of a gene. alleles occur at the same locus on homologous chromosomes.
describe an organism
an individual plant, fungi, animal, or single-celled organism.
why is it important for populations to have some degree of genotypic variation?
because populations with limited variation may not be able to adapt to new conditions if the environment changes, and thus will become extinct.
why is using appearance not the best distinguishing factor when defining species?
because the members of different species can look quite similar. while the members of a single species can be diverse in appearance.
what are examples of biotic and abiotic factors?
biotic = living; plants, animals, etc. abiotic = non-living; water, air, temperature, light, soil, pH
what is taxonomy?
branch of biology concerned with identifying, naming, and classifying organisms.
what element is the cause of climate change?
carbon
what are catabolic and anabolic reactions?
catabolic reactions break down larger molecules into smaller molecules; anabolic reactions build up smaller molecules into larger molecules.`
who proposed natural selection in his book "the origin of species"?
charles darwin
compare and contrast asexual and sexual reproduction
comparison: both forms of reproduction contrast: in sexual reproduction, two parent cells come together to form an entirely new cell, while in asexual reproduction, the cell replicates itself into a copy of itself.
how is darwin's theory of evolution different from lamarck's?
darwin said that only the fit survive, while lamarck believed that the less fit would adapt rather than die off.
what is the gradualist model of speciation?
darwin's theory was that evolutionary changes occur gradually, so this explains the pace of evolution. speciation occurs after populations become isolated, with each group continuing slowly on its own evolutionary pathway.
what is the geological time scale?
division of earth's history based off of the geology of time, climate, and the evolution of life
what is the fossil record?
evidence about the history of life on earth found through fossils. it also shows how different groups of organisms, including species, have changed over time.
what is evolution? what is an evolutionary tree?
evolution is the inheritable changes in a population over time that make the population better adapted to their environment. an evolutionary tree is a diagram that shows the evolutionary history of groups of organisms.
define the bottleneck effect
evolutionary event in which a significant percentage of a population is prevented from reproducing, therefore reducing variation. population bottlenecks increase the influence of genetic drift
what is phylogeny?
evolutionary history of a group of organisms
what did darwin think caused differences in the beaks of galapagos finches?
food sources
what is speciation?
formation of a new species due to the evolutionary process of descent with modification.
what was the significance of darwin's findings in chile?
found marine shells inland as a result of an earthquake (proved catastrophies)
what was the significance of darwin's findings in andes mountains?
found seashells on top (reinforced slow geological changes)
describe the biological species concept.
gene flow occurs between the populations of a species, but not between populations of different species.
what is genotype and phenotype?
genotype: the combination of alleles that determines a particular trait in an organism; often designated by letters (ex. BB or Aa) phenotype: the visible expression of a genotype (ex. brown eyes)
how do you name something using binomial nomenclature?
genus then species. capitalize genus and ONLY italicize species (no caps)
what is uniformitarianism?
geological processes occur at uniform rates
how did biogeography play a role in darwin's theory of evolution?
he believed similar environments may have caused convergent evolution
what was the significance of darwin's findings in argentina?
he observed that there were raised beaches along the coast (build up over time)
what is homozygous and heterozygous?
homozygous: possessing 2 identical alleles for a particular trait. heterozygous: possessing unlike alleles for a particular trait.
what is the proposed cause of the "current" mass extinction event?
humans. we cause pollution, land use, invasive species, and climate change.
describe how nonrandom mating can cause changes in allele frequency in a population
inbreeding doesn't change allele frequencies, but it does gradually increase the proportion of homozygotes, because the homozygotes that result must produce only homozygotes.
what is the difference between internal and external stimuli? give examples of each.
internal stimuli is something that changes within your body or your body's internal response. ex.) eating when you're hungry external stimuli is your sensitivity to outside variables. ex.) sweating when you're hot/ shivering when you're cold or your sense of touch.
what is the scientific method and why is it important to biologists?
it acts as a guideline for scientific studies and helps guide scientific research, no matter the field of science.
what role did charles lyell's book "principles of geology" play in darwin's understanding of earth?
it gave evidence that earth is subjected to slow but continuous cycles of erosion and uplift
describe how gene flow can cause changes in allele frequency in a population
it increases the variation within a population by introducing novel alleles that were produces by mutation in another population.
explain the theory of inheritance of acquired characteristics and why it is wrong
it is that the use and disuse of a structure can bring about inherited change. this is wrong because we can not physically morph our bodies (ex. extend our necks) to become more adapt. the weak with the less useful traits die and only the strong pass on their genes.
describe an atom
it's the smallest particle of an element that displays the properties of the element.
order the classification of species from most inclusive to least inclusive.
kingdom, phylum, class, order, family, genus, species
what is macroevolution?
large-scale evolutionary change, such as the formation of new species, over a long period of time.
how do molecules show evidence of natural selection?
many organisms use similar chemicals and genes, and the diversity in living organisms is due to slight differences in this set of genes.
nonrandom mating
mating that does not occur on a purely random basis; inbreeding and sexual selection
define the founder effect
mechanism of genetic drift that occurs when a new population is established by a small number of individuals, carrying only a small fraction of the original population's genetic variation. the alleles carried by these individuals often, by chance, do not occur in the same frequency as in the original population.
define gene flow
movement of alleles among populations by migration of breeding individuals
describe each step of the scientific method
observation: a formal way of watching the natural world. can be observed by the scientist themself or by others before hypothesis: a proposed explanation made on the basis of limited evidence as a starting point for further investigation. *must be a statement experiment: testing the hypothesis to determine if it is valid *must be controlled and repeatable conclusion: either support or deny the hypothesis and back it up with data publication: publish results for others to study and review for their own research
what are unicellular organisms?
organisms composed of only one cell that cannot be seen without the aid of a microscope. ex.) amoeba
what are multicellular organisms?
organisms that are made up of many cells. ex.) humans
how did george cuvier contribute to the theory of evolution?
proposed catastrophism (species disappear because of catastrophies)
how did james hutton contribute to the theory of evolution?
proposed gradualism (that changes take time)
how did jean-baptiste de lamarck contribute to the theory of evolution?
proposed that actual organisms change over time
how did charles lyell contribute to the theory of evolution?
proposed uniformitarianism (geological processes occur at uniform rates)
what role did fossils play in darwin's theory of evolution?
proved that species arent fixed and change over time
what is binomial nomenclature?
scientific name of an organism
how does anatomical evidence show evidence of natural selection?
shows that different species share vestigial structures that reveal their common descent
explain how heterozygotes maintain variation in a population
since heterozygotes have both the dominant and recessive genotype, they can pass on recessive genotypes through offspring, thus maintaining variation
what is microevolution?
small, measurable evolutionary evolutionary changes in a population from generation to generation; change in allele frequencies within a population over time.
what is meant by the phrase "common descent with modification"?
species can share a similar ancestry while being different as forms of adaptations through natural selection. ex.) finches
what is catastrophism?
species disappeared due to local catastrophic events
what is biogeography?
study of the geographical distribution of life-forms on earth
how does biogeography show evidence of natural selection?
such distributions are consistent with the hypothesis that, when forms are related, they evolved in one locale
describe industrial melanism in terms of microevolution
that is the increase in the frequency of a dark phenotype due to pollution. this shows that gene pool frequencies do take place as microevolution occurs.
describe bioethics
the branch of ethics concerned with the development and consequences of biological technology ex.) genetic engineering
what is energy?
the capacity to do work.
what do scientists mean by the term climate change?
the changes in normal cycles of the earth's climate that may be attributed to human activity.
describe an organ
the combination of two or more different tissues performing a common function.
what is survival of the fittest?
the difference in rates of survival and reproduction.
describe a cell
the fundamental unit of life. lowest level of biological organization that has all of the characteristics of life.
what is homeostasis? give examples of homeostasis in biology.
the maintenance of internal conditions within certain physiological boundaries. ex.) internal body temperature or blood sugar
what is natural selection?
the mechanism of evolution caused by environmental selection of organisms most fit to reproduce; results in adaptation to the environment.
what is fitness
the reproductive success of an individual relative to other members of a population
what is paleontology?
the science dedicated to discovering and studying the fossil record and, from it, making decisions about the history of species.
what is biology?
the scientific study of life.
what is systematics?
the study of the diversity of organisms to classify them and determine their evolutionary relationships
what is science?
the study of the natural world through it's use of the scientific method and other forms of analysis and study.
define assortative mating
the tendency to be attracted to people who are similar to us
what is a fossil?
the traces and remains of past life or any other direct evidence of past life.
describe a molecule
the union of two or more atoms of the same element; also, the smallest part of a compound that retains the properties of the compound.
what is a controlled variable?
the variable that is kept the same throughout an experiment.
what is an independent variable?
the variable that is manipulated in an experiment.
what is a dependent variable?
the variable that is observed, measured, or counted.
what is a gene pool?
the various alleles at all the gene loci in all individuals in a population.
describe a biosphere
the zone of air, land, and water at the surface of the earth in which organisms are found; encompasses all the ecosystems on earth.
what are reproductive barriers? what are their importance in speciation?
they are the isolating mechanisms that prevent successful reproduction. they're important because for two species to be separate, they must be isolated so that gene flow cannot occur between them.
describe how the Hardy Weinberg principle can be used to explain the process of microevolution
they made the equation that can measure the genotype and allele frequencies of a population. this can be used in the process of microevolution because it's the math behind that theory of evolution
summarize the concept of heterozygote advantage.
they still can have access to a recessive phenotype which increases their fitness.
how do fossils show evidence of natural selection?
they tell us about the history of life
what are the limitations of the biological species concept?
this applies only to sexually reproducing organisms and cannot apply to asexually reproducing organisms. even with this, though, because sexually reproducing organisms are not always as reproductively isolated as expected.
describe how genetic drift can cause changes in allele frequency in a population
this is the change in the allele frequencies of a gene pool due to chance. this can increase or decrease depending on which member of a population die, survive, or reproduce with one another.
what is disruptive selection? give an example
this is when two or more extreme phenotypes are favored over any intermediate phenotype. this favors polymorphism. ex.) finches on the galapagos islands
what is directional selection? give an example
this occurs when an extreme phenotype is favored and the frequency distribution curve shifts in that direction. ex.) resistance to antibiotics
what is stabilizing selection? give an example
this occurs when an intermediate phenotype is favored. extreme phenotypes are selected against, and the individuals near average are favored.
what is the punctuated model of speciation?
this says that a period of equilibrium (no change) is punctuated (interrupted) by speciation. this suggests that transitional links are less likely to become fossils and less likely to be found. when a new isolated subpopulation expands, it replaces the existing species.
describe postzygotic isolating mechanisms
those that occur after the formation of a zygote. they prevent hybrid offspring (reproductive product of two different species) from developing or breeding, even if the reproduction attempt was successful.
describe prezygotic isolating mechanisms
those that occur before the formation of a zygote. they prevent reproductive attempts and make it unlikely that fertilization will be successful if attempted.
what was the main purpose of the HMS beagle?
to expand the navy's knowledge of natural resources in south america.
what is epigenetics?
transmission of genetic information by means that are not based on the coding sequences of a gene.
what is gradualism?
variation is gradual in nature and happens over time
what are emerging diseases?
viruses that a relatively new to humans. changes in human behavior and use of technology can also result in new diseases, as well as globalization and exposure to animals or insects.
why can we not anticipate natural selection?
we don't know when the environment will change and adaptations will need to be made
define random mating
when individuals select mates and pair by chance, not according to their genotypes or phenotypes.
what is adaptive radiation? give an example.
when many new species evolve from a single ancestral species. ex.) galapagos finches
describe how mutations can cause changes in allele frequency in a population
without these, there can be no new variations among members of a population on which natural selection can act.