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Biology Exam 4
Terms in this set (165)
DNA Technology's tools apply to individual genes or entire genomes
-DNA produced by combining DNA from different sources
-genetic material or DNA from multiple organisms that gets combined and the organism that receives that recombinant DNA is a transgenic organism
organism that is genetically engineered by inserting a gene from another organism
-uptake recombinant DNA
-genetically engineered bacteria that contain genes from humans or other species and produce proteins or that species; used commercially to produce clotting factors, interferon, insulin, and other products
-generally done by using a plasmid (an extra little circle of DNA that some bacteria have), we take source DNA and cut the DNA and plasmid using restriction enzymes. We do that in such a way that the DNA that we cut can be spliced together with the plasma DNA. We then can get our recombinant DNA to be taken up by bacteria and then those bacteria will express those proteins that the DNA encoded for.
-Recombinant DNA from a transgenic bacteria that infects the plant's cells
-has DNA that sliced from multiple sources and the recombinant bacteria will infect the plant cells to get genes into the plant.
-Recombinant DNA from viruses that infect gamete or fertilized egg of animal
-taking recombinant dna and pack it into a virus and the virus will infect the animal at an early age so that when the animal grows up every cell is containing the gene that the virus will insert into the animal genome
-determining the order of nucleotide bases in a gene or DNA fragment
-Tells us the nucleotide sequence of genes, chromosomes, or entire genomes
PCR (polymerase chain reaction)
-is used to copy and amplify minute quantities of DNA
-take a selective piece of DNA and produce millions of copies of the DNA sequence. The manipulation of the temperature in the test tube will cause the strands of the target sequence to separate and open up
-Produces millions of copies of a selected DNA sequence
Basic steps/ components needed of PCR
-Primers- put primers for DNA replication to happen; go to the right spot by complementary base pairing, PCR uses primers to get replication started
-Target DNA- the DNA we want to amplify
- DNA Polymerase-enzyme responsible for building the new DNA sequence; elongates the strand to create two new strands, DNA polymerase replicates the strand, starting at the primer.
-A procedure that analyzes DNA fragments to determine whether they come from a specific individual.
-Uses most variable parts of the genome to detect genetic differences
-DNA profiling detects genetic differences
STRs (short tandem repeats) (DNA profiling)
-Sequences of a few nucleotides that are repeated in noncoding regions of DNA
-DNA sequencing shows how many short tandem repeats (STRs) are in a person's genome.
Stem cells and cloning add new ways to copy cells and organisms
Stem cells are special because they can develop into different types of cells.
unspecialized cells that are able to renew themselves for long periods of time by cell division
embryonic stem cells
-embryonic cells, which can develop into any type of body cell
- found in early developing embryos
adult stem cells
-stem cells that are found in adults that can differentiate and form a limited number of cells
-found in bone marrow
-capable of becoming a limited subset of cell
-more limitations in usage but avoid the ethical issues that embryonic cells
Stem cells with the potential to differentiate into any type of cell.
Cells that are capable of developing into most, but not all, of the body's cell types
-Making a genetically identical copy of DNA or of an organism.
-Cloning, or asexual reproduction, is common among single-celled organisms such as bacteria, archaea, and many protists.
somatic nuclear transfer
-The nucleus of a fully differentiated cell is transferred into an enucleated egg (ovum). The nucleus can undergo reprogramming to initiate animal development and give rise to all of the cells of a mature organism.
- how dolly was made
-Somatic cell nuclear transfer is used to clone animals
-A short, labeled, single strand of DNA or RNA used to locate its complementary strand in a quantity of DNA
-DNA's ability to complementary base pair with itself; a single stranded DNA piece with a fluorescent label and is trying to detect genes that are linked to a disease
-DNA probes detect specific sequences
-A DNA probe is a single-stranded sequence that is complementary to a known region of DNA, such as a cystic fibrosis allele.
Evolution acts on populations
Evolution explains the features of all organisms, from microbes to humans.
-a change in the genetic composition, usually measured by allele frequency in a population over time
-Evolution occurs when there are changes in heritable traits from generation to generation. Some changes lead to the development of different species.
Different forms of a gene
-Number of times that an allele occurs in a gene pool compared with the number of alleles in that pool for the same gene
ex: 70% DD D=.7
30% dd d=.3
-In a population, allele frequencies change from one generation to the next, over time.
-Evolution does not occur in individuals, since an individual's alleles do not change.
entire collection of genes and their corresponding alleles
Natural selection molds evolution
-a heritable trait that provides some kind of advantage
-Adaptations enhance reproductive success
-A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.
-population level phenomenon- individuals do not evolve
-Natural selection molds evolution
-Natural selection does not create alleles. Instead, it strongly selects for alleles that arise by chance.
-Breeding organisms with specific traits in order to produce offspring with identical traits.
-Artificial selection changes allele frequencies
Natural selection can shape populations in many ways
Three modes of natural selection
1. directional selection
2. disruptive selection
3. stabilizing selection
-Natural selection in which individuals at one end of the phenotypic range survive or reproduce more successfully than do other individuals.
-Directional selection favors one phenotype over another
-natural selection in which individuals at the upper and lower ends of the curve have higher fitness than individuals near the middle of the curve
-Disruptive selection favors extreme phenotypes
-form of natural selection in which individuals near the center of a distribution curve have higher fitness than individuals at either end of the curve
-Stabilizing selection favors intermediate phenotypes
-situation in which selection maintains two or more phenotypes for a specific gene in a population
-how we keep more than one genotype in a population
-Greater reproductive success of heterozygous individuals compared to homozygotes; tends to preserve variation in gene pools.
-ex: sickle cell allele
Sexual selection directly influences reproductive success
Sexual selection results from variation in the ability to obtain mates.
Differences in physical characteristics between males and females of the same species.
A direct competition among individuals of one sex (usually the males in vertebrates) for mates of the opposite sex.
Selection whereby individuals of one sex (usually females) are choosy in selecting their mates from individuals of the other sex; also called mate choice.
Evolution occurs in several additional ways
-ultimate origin of genetic variation
-Mutations are random changes in the sequence of DNA. They can be harmful, but many are harmless and some are beneficial.
-Beneficial mutations are passed on to the next generation, so their frequency increases over generations.
-random change in allele frequencies that occurs in small populations
-Genetic drift is random sampling error. Allele frequencies can shift dramatically, and often become eliminated, when only part of a population survives to reproduce.
founder effect (genetic drift)
-Genetic drift that occurs when a few individuals become isolated from a larger population and form a new population whose gene pool composition is not reflective of that of the original population.
-When only a few individuals establish a new population, the allele frequency might change.
bottleneck effect (genetic drift)
-Genetic drift resulting from the reduction of a population, typically by a natural disaster, such that the surviving population is no longer genetically representative of the original population.
-A population bottleneck occurs if a disaster drastically reduces the size of a population.
gene flow (migration)
-The transfer of alleles from one population to another, resulting from the movement of fertile individuals or their gametes.
-How gene flow affects adaptation- some genes can spread that aren't well adapted to the population or to the environment
-Gene flow moves alleles between populations. This might affect the allele frequencies in both populations.
-Migration causes gene flow and ultimately reduces genetic differences between populations.
-Mating among individuals on the basis of their phenotypic similarities or differences, rather than mating on a random basis
-anything that makes mating not random; some geographical barrier or sexual selection
-Sexual selection and artificial selection can alter mating patterns in a population, preventing random mating.
Clues to evolution lie in the earth, body structures, and molecules
geologic time scale
scale used by paleontologists to represent evolutionary time
Three Eras of the Phanerozoic Eon
four types of data that document evolution
Fossils record evolution
-Fossils are dated by measuring 14C
-Anatomical relationships reveal common descent
-The preserved remains or traces of an organism that lived in the past
- =at least 10,000 years old
Ways fossils form
Limitations of the fossil record
habitat bias, taxonomic and tissue bias, temporal bias, abundance bias
Methods of dating fossils
-absolute dating/ radiometric dating
-Method of determining the age of a fossil by comparing its placement with that of fossils in other layers of rock
-use strata or layers to help us understand how old things are relative to one another; we don't have an actual number
-Relative dating dates fossils according to layer of rock
-A technique used to determine the actual age of a fossil
-more specific timeframe but still a rough estimate
-Absolute dating dates fossils using chemistry
-Living organisms use carbon isotopes 14C and 12C
-the process of measuring the absolute age of geologic material by measuring the concentrations of radioactive isotopes and their decay products
-carbon 14 dating
Process of estimating age of once living material by measuring the amount of radioactive isotope of carbon present in material.
Biogeography considers species' geographical locations
-study of the distribution of organisms around the world
-tells us how the earth used to look
A theory stating that the earth's surface is broken into plates that move.
A supercontinent containing all of Earth's land that existed about 225 million years ago.
-one large land mass that over many millions of years that the continents drifted apart
Anatomical comparisons reveal common descent
Homology (homologous structures)
Similarity in characteristics resulting from a shared ancestry.
Analogy/ analogous structures
-A comparison of two different things that are similar in some way
-something superficially similar or has a similar function but that structure is not derived from a common ancestor, rather this came from convergent evolution
Process by which unrelated organisms independently evolve similarities when adapting to similar environments
traits that currently don't have a function but appear to have had one in the past
Molecules Reveal Relatedness
-Amino acid sequences
a group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding.
Definition of a species as a population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but are not able to produce viable, fertile offspring with members of other populations.
biological species concept
-Definition of a species as a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but do not produce viable, fertile offspring with members of other such groups.
-How species are defined under BSC- reproductive isolation
-Limitations of BSC- cannot apply to a sexual reproducing species, not useful when looking at fossils
-Modern biologists define species by reproduction
Reproductive barriers cause species to diverge
-Separation of species or populations so that they cannot interbreed and produce fertile offspring
-Reproductive barrier that prevents a species from mating
-barriers prevent the formation of an embryo
habitat isolation (prezygotic)
-populations live in different habitats and do not meet
temporal isolation (prezygotic)
active or fertile at different times
behavioral isolation (prezygotic)
different courtship activities
mechanical isolation (prezygotic)
mating organs or pollinators incompatible
gametic isolation (prezygotic)
gametes cannot unite
-Barriers that prevent the hybrid zygote from becoming a fertile adult.
-hybrid individuals have reduced fitness
hybrid inviability (postzygotic)
hybrid offspring fail to reach maturity
hybrid infertility (postzygotic)
hybrid offspring unable to reproduce
hybrid breakdown (postzygotic)
second-generation hybrid offspring have reduced fitness
Spatial patterns define three types of speciation
-The formation of new species in populations that are geographically isolated from one another.
-With no gene transfer between the two populations, each proceeds down its own evolutionary line.
-Eventually, genetic differences between the populations give rise to reproductive isolation (either prezygotic or postzygotic).
-The formation of new species in populations that live in the same geographic area
-polyploidy- pretty uncommon in animals, common in plants; doubling of a genome. Not going to be able to reproduce properly with other species; Polyploidy can form "instant" new species
-Sympatric speciation occurs in a shared habitat
Speciation may be gradual or may occur in bursts
-adaptive radiation: An evolutionary pattern in which many species evolve from a single ancestral species
-speciation followed by mass extinction
Biological classification systems are based on common descent
The science of classifying organisms
Taxonomy organizes species into groups
the study of evolutionary relationships among species
diagram showing evolutionary relationships of organisms with a common ancestor; resembles a tree
Evolutionary history of a species
taxonomic ranks in order
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
Diagram that shows the evolutionary relationships among a group of organisms
DNA technology manipulates DNA
Manipulating DNA for practical purposes is called DNA technology.
DNA Technology's Tools
Recombinant DNA, DNA sequencing, polymerase chain reaction (PCR), DNA profiling
Using DNA Technology to Copy Cells and Organisms
Stem cell research, cloning
Using DNA Technology in Medicine
DNA probes, gene therapy, CRISPR-Cas9 gene editing
DNA technology can be applied to genes and genomes
-The genome of any organism can be manipulated.
-Changing an organism's genes changes the proteins it expresses.
Transgenic organisms contain DNA from multiple sources
Transgenic organisms have many useful applications, such as manufacturing pharmaceuticals, engineering hardy crops, and testing human genetic diseases in mice.
Scientists use viruses to create transgenic animals
Recombinant DNA combines with chromosomes when early embryonic cells are infected by genetically modified viruses.
Scientists use bacteria to create transgenic plants
Recombinant T1 plasmids combine with plant chromosomes when the cells are infected by genetically modified bacteria.
DNA sequencing starts with DNA replication in a tube
Researchers put the unknown DNA sequence, primers, nucleotides, and replication enzymes together.
Replication of the DNA occurs as it would in a cell.
DNA sequence shows how different organisms are unique
Most human DNA is "noncoding" - only about 1.5% of it encodes proteins.
PCR replicates DNA in a test tube
Scientists can replicate DNA using the polymerase chain reaction (PCR).
Survival of the "fittest"
Fitness describes an organism's genetic contribution to the next generation.
Fitness is reproductive success
condition that occurs when the frequency of alleles in a particular gene pool remain constant over time
Some species cannot be defined by reproduction
-Asexually reproducing species and species represented by fossils never interbreed.
-Some organisms are able to interbreed, but in nature they do it very rarely or even never.
DNA analysis helps to define species
Researchers compare the nucleotide sequence of genes that organisms have in common.
A polyploid organism is reproductively isolated from diploids, because the chromosome numbers differ, creating hybrid inviability.
Cladistics distinguishes between traits that are ancestral (inherited) and traits that are derived (not inherited from an ancestor).
Cladistics is based on shared derived traits
A cladogram is a type of phylogenetic tree
This diagram is a tool used to develop hypotheses about the relationships between groups of organisms.
Cladograms can be based on observed physical features
Cladograms can be based on molecular sequences
A clade is a group of organisms consisting of a common ancestor and all of its descendants.
The basic unit of a cladogram is a clade
Cladograms identify the last common ancestor
The last common ancestor shows how groups are related
Many traditional groups of organisms are not clades
A clade is also called a monophyletic group.
Crocodiles, lizards, snakes, and turtles are reptiles, but these groups do not form a clade.
A paraphyletic group includes a common ancestor, but excludes some of the descendants of an ancestor.
"Reptiles" is a paraphyletic group
A polyphyletic group excludes the most recent common ancestor of its members. Birds and mammals are endotherms, but their common ancestor was not endothermic.
"Endothermic animals" is a polyphyletic group
protein that cuts double stranded DNA at a specific base sequence
Genetic material that has been cut with restriction enzymes and splices with DNA from other organisms
an individual with recombinant DNA
Determines the nucleotide sequence of DNA fragments
PCR (polymerase chain reaction)
Amplifies DNA in a test tube using the cells replication machinery
Uses DNA sequencing and PCR to detect genetic differences among individuals
cells found n embryos and some adult tissues that can give rise to other cell types
Making an identical copy of an organism
somatic nuclear transfer
a type of cloning that combines a nucleus taken from one individuals body cell with a denucleated egg cell from another individual to produce the first cell of a new organism
a single stranded sequence of DNA, labeled with a radioactive isotope or fluorescent tag, used to detect the presence of a known sequence of nucleotides
interbreeding members of the same species
small, generation by generation changes to a population's gene pool
large-scale evolutionary events, such as the appearance of new species
Formation of new species
the death of all members of a species
separation of species due to factors that prevent reproduction
prezygotic reproductive isolation
separation of species due to failure to form a zygote
postzygotic reproductive isolation
separation of species due to selection against hybrid offspring
the offspring of individuals of two different species
features present in the common ancestor of a clade
features of an organism that are different from those found in a clade's ancestors
group of organisms consisting of a common ancestor an all of its descendants; a clade
comparator group outside the group being studied; useful for identifying ancestral traits
group of organisms consisting of a common ancestor and some, but not all, of its descendants
group of organisms that excludes the more recent common ancestor
the combined study of taxonomy and evolutionary relationships among organisms
Selective breeding is also known as ____
descent with modification
one extreme phenotype is fittest and the environment selects against the others
extreme phenotypes are less fit than the optimal intermediate phenotype
two or more extreme phenotypes are fitter than the intermediate phenotype
As environmental conditions change, the phenotypes that natural selection favors will also change.
Evolution occurs in ___
Evolution occurs when there are no changes in traits from generation to generation.
Anatomical structures are ____ if they are superficially similar but did not derive from a common ancestor.
At what point did the present-day continents form and begin to drift apart?
Fossil evidence is complete
According to the theory of _____, forces acting deep within the planet move Earth's land masses.
Geologic timescales are used to divide the history of Earth into eons and eras.
Reproductive isolation is postzygotic if ____
barriers prevent the formation of an embryo
homologous structures are not present
new species form and can breed with other species
hybrid individuals have reduced fitness
hybrid individuals have reduced fitness
Habitat isolation is an example of prezygotic reproductive isolation.
A barrier physically separates a population into two groups that cannot interbreed
Part of a population enters a new habitat bordering the range of the parent species
Populations diverge genetically while living together
Which taxonomic group is most specific (i.e. least encompassing)?
A clade is also called a monophyletic group
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