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BIO1130 Keywords for Lecture 3

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Biology Keywords 3Adaptive radiation A burst of speciation associated with a move into new situationsDemonstrated when patterns of evolution appeared to progress from living in wooded habitats to living in open grasslands Also called diversification Demonstrated when patterns of evolution appeared to progress from living in wooded habitats to living in open grasslandsAdvancedSame as a derived character essentially A new version of a trait found in the most charactersrecent common ancestor of a group It may or may not be superior to the primitive character it came fromAllele One member or a pair or any series of genes occupying a specific spot on a chromosome that controls the same trait Eg a pair of alleles controlling the same traiteye colour one allele codes for blue eyes another for brown eyesAllele frequencies Measurement determining how frequent the allele expression of a particular gene arises in a population The result should be in close correlation with the laws of natural selection where more favourable alleles should become dominant in a species over time or are present due to a niche environment where a particular allele would prove advantageousAllopatricCan occur when a physical barrier subdivides a large population into two separate speciationpopulations or when a small population becomes separated from a species of the main geological distribution due to genetic drift or because one population moves towards another population to get hybridization Common in large mammalsThis separation occurs sometimes when a barrier divides a large population into two or more units either by vicariance or dispersal the movement of organisms away from their place of origin due to weather for example It goes as follows1Two populations become geographically separated preventing gene flow between them2Populations experience distinct mutations as well as different patterns of natural selection and genetic drift they may accumulate genetic differences that isolate them reproductivelyAllopolyploidy Hybridization of different species When two closely related species hybridize and subsequently form polyploidy offspringIt is extremely rapid causing a new species to arise in one generation without geographic isolationAnagenesis Slowly morphing into another species Evolutionary pattern resulting in linear descent and not to divergence or branching to additional species The slow accumulation of evolutionary changes in a lineage over timeApomorphy Derived characters within a group evolutionary lineage As you obtain more of the apomorphies you become more advanced Organisms move up the evolutionary true as characters sequentially get more and more complex with apomorphiesAutoapomorphy The signature of your species no one else has it It is an apomorphy in a single taxonAutopolypoloidy It is a complete increasedoubling of the genome as a result of the mating process Arises from chromosome duplications within single species When a diploid 2n individual may produce tetraploid 4n offspring each with four complete chromosome setsIt occurs through an error in either mitosis or meiosis so that gametes spontaneously receive the same number chromosomes as a somatic cellBehaviouralPrezygotic reproductive isolating mechanism in which two species do not mate because isolationof difference sin courtship behaviors also known as ethological isolation Results when the signals used by one species are not recognized by another two organisms cant mate because the females dont recognize the signal created by the male These signals are specific which often differ dramatically between species to identify the species of a potential mateSexual selection drives the evolution of mate recognition signalsEg Fireflies Each species has a unique flashing sequence that the male produces The males are flying and sending out bursts of light that are speciesspecific Females are watching and as soon as they see the signal that belongs to their species the female flashes the signal to the male the male starts flying to the femalethis is how they find each other to mate Exception female sees male from another species but she knows the call of that female from that specific signal male gets lured in and when he goes to try mate him she kills him and eats himthis to get protein for her eggs and when she is full she will return back to her own species signal to mate againBeneficial mutation When a mutation is advantageousBiological species Coined this only in the 1940s Up until this point in time no one really knew how to describe species Defines a species as a group of organisms that can successfully interbreed and produce fertile offspring and is completely isolated from other species Fails to deal with evolutionary past and the microbial world We cant bring fossils back to see if they interbred back then consisting of 99 of all organisms that lived and because it requires sexual reproduction bacteria and prokaryotes are not included They do not mate with meiosis and sexual recombination of gametes This concept only works with things that are living right now there is only 1 of organisms that have existedBottleneck effect Comes into play when you have a population of organisms that has undergone some natural catastrophedisaster that dropped the population down to very few individuals in the same placehabitat in same circumstances With only a few surviving individuals there is only a limited about of variability that survived some alleles are completely eliminated This cause of genetic drift greatly reduces genetic variation even if the population numbers later rebound Usually resulting from habitat destruction that isolates organisms Eg American bison very susceptible to diseases because they all have the same variability Character polarity The ordering of different states of a taxonomic character from ancestral to derived in an evolutionary transformation seriesChromosomalOccurs if a broken segment reattaches to the same chromosome from which it was lost Inversionbut reversed in orientation so that the order of genes is reversed It has essentially the same effects as translocationsgenes may be broken internally by the inversion with loss of function or they may be transferred intact to a new location within the same chromosome producing effects that range from beneficial to harmfulChromosomalDNA in chromosomes can be broken by agents such as radiation chemicals or viruses mutationThis broken chromosome fragment may be lost or may reattach to the same or different chromosomes naming it a chromosomal mutation It is a source of disease and disability as well as a source of variability during evolutionChromosomalOccurs if a broken segment is attached to a different nonhomologous chromosometranslocation Reciprocal translations meaning that two nonhomologous chromosomes exchange segments resemble genetic recombination except that the two chromosomes involved in the exchange do not contain the same genesClade A monophyletic group of organisms that share homologous features derived from a
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