Eemb 22 studyguide

eshapeesha's version from 2017-05-05 08:52



Question Answer
Adaptationchange over time due to survivability
Adaptive radiationorganisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, creates new challenges, or opens new environmental niches.
Allele frequencyrelative frequency of an allele at a particular locus in a population
Allelesone or 2 more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.
Artificial selectionwhen man particularly picks the traits they want extended in a population.
Binomial nomenclaturegenus, species
Bottleneck effecta severe reduction in population brought about by intense selection pressure or natural disaster. survivors gene pool ay no longer represent the original population, by chance certain alleles may be over represented, under represented or eliminated; genetic drift may continue to alter the gene pool and reduce variation if population size is small.
Chromosomesthreadlike structure of nucleic acids and protein found in the nucelus of most living cells, carrying genetic information in the form of genes.
Continuous variationhas no limit on the value that can occur within a population.
Darwinian selectionselection of traits that are more suitable for the environment.
Directional selectiona mode of natural selection in which an extreme phenotype is favored over other phenotypes, causing the allele frequency to shift over time in the direction of that phenotype.
DNAcompound that stores biological info, double helix w a hdrogen bond, inc nucleotides w ribose sugar, phosphate, and nitrogen containing compounds. the sequence of bases is genetic info and varies among species and individual.
Disruptive selectiondescribes changes in population genetics in which extreme values for a trait are favored over intermediate values. In this case, the variance of the trait increases and the population is divided into two distinct groups.
Divergenceleads to differences between gene pools of the separate populations through mutation, natural selection, genetic drift.
Eukaryoteshave a nucleus and membrane bound organelles. the nucleus stores information, contains chromosomes
Ecological isolationisolation due to adaptation to different micro climates in the same habitat
Ethological isolationisolated by behaviors, copulation proceeded by courtship displays, reciprocity produces sexual stimuli.
Evolutioninception of man on earth and life occurred billions of years ago and man and ape emerged from a common ancestor and life changes occur via adaptation
Fecundityability to produce an abundance of offspring
Darwinian fitnesscontribution of a genotype to the next generation, relative to the contribution of the average individual
Founder effectswhen a few individuals become isolated from a larger population. they migrate to a new habitat and the isolated gene pool may no longer reprersent the original population.
Gene poolcollection of the genes in the population. every option
Genetic driftrandom change in allele frequencies over the generations, brought about by chance. changes in allele frequencies due to genetic drift occur regardless of the fitness of individuals. genetic drift either favors the elimination or fixation of an allele. tends to reduce genetic variation
Genotypethe gene
Genomecomplete heritable genetic identity, the sequence
Geographic isolationisolating by distance or geogrpahic barriers relative to the size of the organism
Genetic loadthe difference between the fitness of an average genotype in a population and the fitness of some reference genotype
Ecogeographic variationvariation based on the ecology and location of a place
Genelocus of dna passed on, one unit of heredity
HomoninsThe human lineage, including our most direct ancestors, that finally diverged from the african apes are known as the Homonins.
Ethologystudy of animal behavior
Mass extinctionwhen theres a sudden die off
Hybridizationsplit DNA of 2 species then recombine and split again. it becomes harder to break the bonds making for more closely related species.
Mate choiceThe process by which changes in the genetic composition of populations of organisms occur in response to environmental changes.
Meiosishalfs the DNA pairs to produce haploid gametes.
Organic evolutionThe process by which changes in the genetic composition of populations of organisms occur in response to environmental changes.
Mutationpermanent change in a cell's DNA sequence bc of failures in proofreading and repair mechanisms. passed on.
Natural selectionincrease the number of frquencies of certain genotypes that confer reproductive success based on fit= how well adapted to environment. acts on phenotypes not genotypes.
Organismal evolutionevolution of an organism
Phenotypevisible, physical trait
Polymorphic variationa variation in phenotype of a population
Post-mating barriersFactors which cause species to mate with their own kind
Postzygotic isolationafter fertilization, more difficult.
Phylogenyline of descent (based on species distance in terms of time)
Pre-mating barriersGenomic incompatibility, hybrid inviability or sterility.
Prezygotic isolationisolating mechanisms before or during fertilization. includes ecological, geographic, temporal, ethological, mechanical isolation
Seasonal isolationA type of ecological reproductive isolation in which different species become reproductively active at different times
Prokaryotesunicellular, no nucleus and no membrane bound organelles.
Recessivea gene that needs to be more common to present itself
Dominantthe gene that there only needs to be one of to present itself
Maladaptive traitstraits that hurt survivability
Speciationchange in allelic frequencies that are significant enough to mark the formation of daughter species from parent species. occurs due to an accumulation of genetic changes that promote a significant difference between populations depending on how gene flow between populations is interrupted. occurs through abrupt events and adaptation to different environments.
Stabilizing selectionphenotypes that tend toward an equilibrium of 2 extremes.
Mechanical isolationisolated by incompatible reproductive part, size, or shape.


Question Answer
Describe the classification scheme that biologists use to classify and order organisms?two part naming system . first genus (group of species that share a unique set of features) then a specific epithet. the naming of animals is called taxonomy. species share morphological traits, biocemical traits, behavioral traits.
species ranked intotaxon- group of organisms that share a unique set of traits
speciesgroups of individuals that can interbreed
3 domainsbaceria, archaea, eukarya
darwinvariation exists and it is what evolution acts upon. believes in gradualism- earth is old and has been slowly changing. he also thought of natural selection
mendelcross bred pea plants to figure out genetics and how variation is passed on.
kimuralooked at population genetics and saw how allele frequency shapes how genetics works on the population
Identify the age of the Earth and identify the age that first evidence of life on the planet was discovered? earth is 4.3 billion years old, 3.4 billion years ago anaerobic cells.
oxygen on earth?3.5 bill years ago bacteria and archaea diverged, then some bacteria began to capture light and perform photosynthesis that didnt produce oxygen. then cyanobacteria fully photosynthesizes w oxygen (2.7 bill). oxygen began to accumulate in air and water, allowing organisms that thrived in high oxygen areas at an advantage making aerobic respiration widespread which is efficient energy wise. also this extra oxygen creaed the ozone layer which blocks earth from uv radiation from reaching earth's surface. then came eukaryotes
origin of eukaryotesan early eukaryote with a genome derived from an archaeal ancestor engulfed or otherwise partnered with a bacterial cell. over time, bacterial genes related to metabolism and membrane formation migrated into the nucleus and the corresponding archaeal genes were lost. this resulted in a composite genome. the earliest eukaryotes were also the first protists. the first of these were multicelled and had cellular division of labor.
origin of animalsanimal diversity increased during a great adaptive radiation in the cambrian. after that all major animal lineages were represented in the seas.
Describe the theory of natural selection and describe how it serves as the main selective agent of evolution?natural selection increases the frequencies of certain genotypes that confer reproductive success. this is based on fit, or adaptation to the environment which leads to higher reproduction. natural selection depends on competition, reproductive success, adaptation to the environment, and impacts phenotypes not genotypes. the most fit will pass on their genes with the greatest frequency and the individual with the most offspring will pass on the most genes.
Describe the 3 basic characteristics that are modified to provide adaptations. Provide some examples of adaptive,maladaptive and neutral features in humans and other organisms.morphological traits, physiological traits, and behavioral traits are modified. neutral features- tongue rolling, hair on middle joint. adaptive- nose shape. maladaptive- bad eyesight
Describe the basics of cellular organization,cells can be prokayotic- no nucleus and no membrane bound organelles or eukaryotic- have a nucleus and membrane bound organelles. there are also somatic cells- 2 sets of chromosomes that are diploid. gametes- 1 set of chromosomes which are haploid. there's also DNA
DNA structuredouble helix that is hydrogen bonded. nucleotides are made of ribose sugar, phosphate and nitrogen containing base. nitrogen bases are adenine, thymine, cytosine, and guanine. the sequence of bases along DNA is genetic information. the sequence of bases varies among species and individuals.
types of mutationschromosomal mitations- deletions, duplications, inversions, translocation. not common, can be lethal. usually negative, occassionally positive. there's also point mutation- addition, subtraction, and substitution. this is more common and can result in changes in mrna and proteins.
mutationheritable changes in DNA that give rise to altered gene products. mutations are the only source of new alleles, new alleles may alter the amino sequence of encoded proteins altering their function. wild type alleles produce expected phenotypes and mutant alleles may produce an unexpected phenotype. mutations can be caused by uv light, x rays, chemicals in tobacco smoke.
gene flowthe physical movement of alleles through immigration and emigration
genetic driftrandom change in allele frequencies over the generations, brought about by chance. changes in allele frequencies due to genetic drift occur regardless of the fitness of individuals. genetic drift either favors the elimination or fixation of an allele.
situations that increase the impact of genetic drift on a populationbottleneck effect- a severe reduction in population size brought about by intense selection pressure or natural disaster. (contagious disease, hunting, ,volcanoes) this usually reduces the diversity because there is a small gene pool.
Describe the different types of recombination and 1) crossing over at meiosis- each similar pair of chromosomes line up and can exchange genes. 2) independent assortment at meiosis- puts mixes of maternal and paternal chromosomes into gametes. 3) fertilization- combines alleles from 2 parents.
recombination explain how they increase variation1) interbreeding- sexual reproduction between 2 genetically similar individuals. this increases genetic load (protential harmful negative genes) and decreases the amount of variation in a population. 2) crossbreeding- sexual reproduction between 2 genetically different individuals. this decreases the genetic loa and increases variation

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