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Presentation: Artificial and Natural Selection
Presentation: Artificial and Natural Selection

... has been going on for so long that modern domesticated plants and animals are very different from their ancestors. • People realized that if humans can bring about such changes that a similar process could occur naturally. ...
15.3: Patterns of Evolution
15.3: Patterns of Evolution

... insects—may be based on hox genes. • Finally, geneticists are learning that even small changes in the timing of genetic control during embryonic development can make the difference between long legs ...
Evolution Notes
Evolution Notes

... ___________________________- Body structures on different organisms that are similar in function but did not evolve from the same ancestor. ___________________________- Body structure in an organism that no longer serves its original purpose but was useful to the ancestor Embryo- earliest stage of _ ...
Disruptive selection, also called diversifying selection, is a
Disruptive selection, also called diversifying selection, is a

... Disruptive selection, also called diversifying selection, is a descriptive term used to describe changes in population genetics that simultaneously favor individuals at both extremes of the distribution. When disruptive selection operates, individuals at the extremes contribute more offspring than t ...
Misconceptions About Natural Selection
Misconceptions About Natural Selection

... an all-powerful force, urging organisms on, constantly pushing them in the direction of progress — but this is not what natural selection is like at all. First, natural selection is not all-powerful; it does not produce perfection. If your genes are "good enough," you'll get some offspring into the ...
Ch. 16 Evolution of Populations Name Period ______ 16
Ch. 16 Evolution of Populations Name Period ______ 16

... 7. The frequency of an allele in a gene pool of a population depends on many factors and may be stable or unstable over time. As a basis for understanding this concept: a. Students know why natural selection acts on the phenotype rather than the genotype of an organism. b. Students know why alleles ...
Natural selection
Natural selection

... disadvantages in the struggle for existence. Individuals best suited to their environment survive and reproduce most successfully. These organisms pass their heritable traits to their offspring. Other individuals die or leave fewer offspring. This process of natural selection causes species to chang ...
Evolutionary biology
Evolutionary biology

... Genetic difference  natural selection  the more adaptive one should spread  the observed degree of variation should be low Most difference among alleles are adaptively neutral and accumulated – the reality ...
Mechanisms of Evolution
Mechanisms of Evolution

... • Some alleles are passed on more than others by chance ...
Slide 1
Slide 1

... Changes in the genetic makeup of populations ...
Populations evolution
Populations evolution

... 11-4: Hardy-Weinberg Equilibrium p2 + 2pq + q2 = 1 and p + q = 1 p = frequency of the dominant allele  q = frequency of the recessive allele  p2 = % of homozygous dominant individuals  q2 = % of homozygous recessive individuals  2pq = % of heterozygous individuals ...
bio 11 genetics sep 15
bio 11 genetics sep 15

... Bell shaped curve shows how many organisms have a certain phenotype The two extreme ends have low values and most organisms fall in the middle range Normal distribution ...
16.1 Genes and Variations
16.1 Genes and Variations

... • Bell shaped curve shows how many organisms have a certain phenotype – The two extreme ends have low values and most organisms fall in the middle range – Normal distribution ...
PROCESS OF EVOLUTION I Evolution in a Genetic Context
PROCESS OF EVOLUTION I Evolution in a Genetic Context

...  Inbreeding: It increases both homozygous dominant & recessive  Assortative mating: favors similar phenotypes It divides the population into two or more phenotypes  Sexual selection: e.g., female chose their mates ...
Let’s further study how allele frequencies can change in
Let’s further study how allele frequencies can change in

... 4. Repeat this in as many generations as possible ...
File
File

... You will create a draft and final version of a children’s storybook to help illustrate the process of natural selection (a mechanism for evolution). This will help to illustrate your understanding of how natural selection works. We will be presenting these projects briefly ( a few minutes apiece). N ...
Chapter 23
Chapter 23

... does not change over generations of time. d. Hardy-Weinberg Equation ...
Evolution-Part2
Evolution-Part2

... "The rate of increase in fitness of any organism at any time is equal to its genetic variance in fitness at that time."[1] Or, in more modern terminology: "The rate of increase in the mean fitness of any organism at any time ascribable to natural selection acting through changes in gene frequencies ...
Incomplete penetrance
Incomplete penetrance

... at such a frequency that the rarest could not be maintained by recurrent mutation alone • Practically---a genetic locus is considered polymorphic if one or more of the rare alleles has(have) a frequency of at least 0.01. • Examples: MHC, SNPs, SSRs ...
File
File

... • Mutations and genetic variation occur through the recombining and sorting of meiosis • What cell does a mutation need to occur in, in order to be passed on to its offspring? ...
Population Genetics
Population Genetics

...  If frequencies don’t change over time, evolution is not occurring population in equilibrium  Conditions for HW equations to work  Large gene pool (no genetic drift)  Isolation of population (no gene flow)  No mutations can occur  Random mating  No selective pressure for or against traits (n ...
16 Evolution of Populations and Speciation
16 Evolution of Populations and Speciation

... – Teratogen: Birth defect causing ...
Chapter 17 Evolution of Populations
Chapter 17 Evolution of Populations

... Indiv at outer ends of curve fitness than middle Acts against indiv of intermediate type Can use split of curve into 2 ...
Heredity
Heredity

16 Evolution of Populations and Speciation
16 Evolution of Populations and Speciation

... – Teratogen: Birth defect causing ...
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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.
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