Ch 23 Evolution of Populations
... Sexual Reproduction • Variation arise from • meiosis (crossing over, independent assortment) • Random fertilization ...
... Sexual Reproduction • Variation arise from • meiosis (crossing over, independent assortment) • Random fertilization ...
Genetic Variation is the Key to Natural Selection
... allele is often hidden by a dominant allele. • Occurs even if the gene that is being hidden is lethal. • Ex. most genetic disorders are preserved because of diploidy. ...
... allele is often hidden by a dominant allele. • Occurs even if the gene that is being hidden is lethal. • Ex. most genetic disorders are preserved because of diploidy. ...
Ch 23 Notes
... Especially small populations or islands. GENETIC VARIATION: the substrate for natural selection. Polymorphism is normal variation. So a black cat can have kittens of all different colors. ...
... Especially small populations or islands. GENETIC VARIATION: the substrate for natural selection. Polymorphism is normal variation. So a black cat can have kittens of all different colors. ...
Mechanisms of Evolution
... • A change in the population because of a random event, such as a catastrophe • The smaller the population, the less genetic variety it has. • 2 Types: ...
... • A change in the population because of a random event, such as a catastrophe • The smaller the population, the less genetic variety it has. • 2 Types: ...
15.2 PDQ - Biology with Radjewski
... populations due to migration • Genetic Drift – change in gene frequencies from generation to generation due to random processes • Non-random mating – selection of mates on basis of traits • Mutation – change in DNA • Selection – choosing preferential phenotypes ...
... populations due to migration • Genetic Drift – change in gene frequencies from generation to generation due to random processes • Non-random mating – selection of mates on basis of traits • Mutation – change in DNA • Selection – choosing preferential phenotypes ...
Evolution & Speciation
... colonization by a limited number of individuals from a parent population ...
... colonization by a limited number of individuals from a parent population ...
No Slide Title
... and assortative mating) – Population is large (if appropriately chosen!) – No mutation (but there is) – No migration (but migration occurs) – No selection (but there can be selection) ...
... and assortative mating) – Population is large (if appropriately chosen!) – No mutation (but there is) – No migration (but migration occurs) – No selection (but there can be selection) ...
Natural selection Differential survival or reproduction of individuals
... selection; pressures that affect an individual’s success in mating Splitting of one species into two or more different species members of a species are isolated from one another due to a ...
... selection; pressures that affect an individual’s success in mating Splitting of one species into two or more different species members of a species are isolated from one another due to a ...
Chapter 23 outline
... to maintain stable frequencies of two or more phenotypic forms in a population. Two mechanisms: Heterozygote Advantage – If individuals who are heterozygous at a particular locus have greater survivorship and reproductive success than any type of homozygote, then two or more alleles will be maintain ...
... to maintain stable frequencies of two or more phenotypic forms in a population. Two mechanisms: Heterozygote Advantage – If individuals who are heterozygous at a particular locus have greater survivorship and reproductive success than any type of homozygote, then two or more alleles will be maintain ...
Mechanisms of Evolution
... What drives this ‘speciation’? ISOLATING MECHANISMS • Behavioral• Geographical• Temporal- ...
... What drives this ‘speciation’? ISOLATING MECHANISMS • Behavioral• Geographical• Temporal- ...
How Evolution Works
... Single gene controlling a trait will have only a few (usually 2 or 3 phenotypes) ...
... Single gene controlling a trait will have only a few (usually 2 or 3 phenotypes) ...
Evolution Bingo Review KEY
... c. No __MUTATIONS__ that cause changes in genes. d. No movement of genetic information from one population to another - _IMMIGRATION__/emigration. e. No natural selection (no one is more fit to the environment than another). 5. __ HOMOLOGOUS __ structures, similar structure but different function, c ...
... c. No __MUTATIONS__ that cause changes in genes. d. No movement of genetic information from one population to another - _IMMIGRATION__/emigration. e. No natural selection (no one is more fit to the environment than another). 5. __ HOMOLOGOUS __ structures, similar structure but different function, c ...
Population Genetics
... Modes of selection • Stabilizing selection: middle or intermediate phenotypes selected for, extreme phenotypes selected against i.e. best adapted is “average” • Directional selection: favors one of the extremes over the average and other extreme i.e. favors rare individuals • Diversifying selection ...
... Modes of selection • Stabilizing selection: middle or intermediate phenotypes selected for, extreme phenotypes selected against i.e. best adapted is “average” • Directional selection: favors one of the extremes over the average and other extreme i.e. favors rare individuals • Diversifying selection ...
natural selection
... point of extinction the remaining individuals do not carry a true representation of the original gene pool. – FOUNDER EFFECT – when a small number of individuals colonize a new area they only carry with them a small representation of the total number of the alleles from the gene pool. ...
... point of extinction the remaining individuals do not carry a true representation of the original gene pool. – FOUNDER EFFECT – when a small number of individuals colonize a new area they only carry with them a small representation of the total number of the alleles from the gene pool. ...
Review for Final: Chap 16: Evolulution of Populations
... Polygenic traits are controlled by multiple genes; Single gene traits controlled by 2 alleles. ...
... Polygenic traits are controlled by multiple genes; Single gene traits controlled by 2 alleles. ...
Evolutionary Genetics Field Trip Survey Introduction Cepaea
... Cepaea nemoralis also known as the Grove Snail or Brown lipped snail is one of the most numerous and polymorphic species of land snail in Europe .It is typically found to inhabit woodlands, meadows and residential or inner city gardens, it is nocturnal and usually feeds on dead or decaying vegetatio ...
... Cepaea nemoralis also known as the Grove Snail or Brown lipped snail is one of the most numerous and polymorphic species of land snail in Europe .It is typically found to inhabit woodlands, meadows and residential or inner city gardens, it is nocturnal and usually feeds on dead or decaying vegetatio ...
Polymorphism (biology)
Polymorphism in biology is said to occur when two or more clearly different phenotypes exist in the same population of a species—in other words, the occurrence of more than one form or morph. In order to be classified as such, morphs must occupy the same habitat at the same time and belong to a panmictic population (one with random mating).Polymorphism as described here involves morphs of the phenotype. The term is also used somewhat differently by molecular biologists to describe certain point mutations in the genotype, such as SNPs (see also RFLPs). This usage is not discussed in this article.Polymorphism is common in nature; it is related to biodiversity, genetic variation and adaptation; it usually functions to retain variety of form in a population living in a varied environment. The most common example is sexual dimorphism, which occurs in many organisms. Other examples are mimetic forms of butterflies (see mimicry), and human hemoglobin and blood types.According to the theory of evolution, polymorphism results from evolutionary processes, as does any aspect of a species. It is heritable and is modified by natural selection. In polyphenism, an individual's genetic make-up allows for different morphs, and the switch mechanism that determines which morph is shown is environmental. In genetic polymorphism, the genetic make-up determines the morph. Ants exhibit both types in a single population.Polymorphism also refers to the occurrence of structurally and functionally more than two different types of individuals, called zooids within the same organism. It is a characteristic feature of Cnidarians.For example, in Obelia there are feeding individuals, the gastrozooids; the individuals capable of asexual reproduction only, the gonozooids, blastostyles and free-living or sexually reproducing individuals, the medusae.
