• Study Resource
  • Explore Categories
    • Arts & Humanities
    • Business
    • Engineering & Technology
    • Foreign Language
    • History
    • Math
    • Science
    • Social Science

    Top subcategories

    • Advanced Math
    • Algebra
    • Basic Math
    • Calculus
    • Geometry
    • Linear Algebra
    • Pre-Algebra
    • Pre-Calculus
    • Statistics And Probability
    • Trigonometry
    • other →

    Top subcategories

    • Astronomy
    • Astrophysics
    • Biology
    • Chemistry
    • Earth Science
    • Environmental Science
    • Health Science
    • Physics
    • other →

    Top subcategories

    • Anthropology
    • Law
    • Political Science
    • Psychology
    • Sociology
    • other →

    Top subcategories

    • Accounting
    • Economics
    • Finance
    • Management
    • other →

    Top subcategories

    • Aerospace Engineering
    • Bioengineering
    • Chemical Engineering
    • Civil Engineering
    • Computer Science
    • Electrical Engineering
    • Industrial Engineering
    • Mechanical Engineering
    • Web Design
    • other →

    Top subcategories

    • Architecture
    • Communications
    • English
    • Gender Studies
    • Music
    • Performing Arts
    • Philosophy
    • Religious Studies
    • Writing
    • other →

    Top subcategories

    • Ancient History
    • European History
    • US History
    • World History
    • other →

    Top subcategories

    • Croatian
    • Czech
    • Finnish
    • Greek
    • Hindi
    • Japanese
    • Korean
    • Persian
    • Swedish
    • Turkish
    • other →
 
Profile Documents Logout
Upload
Preview Study Guide
Preview Study Guide

... with a modern understanding of genes. People have long engaged in selective breeding—reproducing plants and animals in such a way that desirable traits are developed, enhanced, or continued. Evolution depends on natural selection, defined above, in which the demands of life in a particular environme ...
Lecture 35 – PDF
Lecture 35 – PDF

... chromosomal polymorphisms within species and chromosomal differences between species indicates that not all major chromosomal alterations are not lost at inception. c) What must happen for the in sequence to increase in frequency to the point where the population becomes polymorphic for the two sequ ...
Directional Positive Selection on an Allele of Arbitrary
Directional Positive Selection on an Allele of Arbitrary

... the next event, t, is given by solving exp( z aðtÞdt) ¼ 1  U , where U is a uniform random number. The next event at time z 1 t is chosen randomly with probability ak ðz 1 tÞ=aðz 1 tÞ, where ak ðz 1 tÞ is the instantaneous rate of event k (e.g., recombination within the favored class), and aðz 1 t ...
File
File

Lecture 19
Lecture 19

... - this suggests the action of positive selection. - however, the mutation actually responsible for rescuing viability was a P-element insertion in the 5’ region of the gene that caused a large reduction in transcription. What do these limited examples tell us about speciation genes? - not surprising ...
Zoo/Bot 3333
Zoo/Bot 3333

Chapter 9: Patterns of Inheritance
Chapter 9: Patterns of Inheritance

... Sex-linked Inheritance Sex-linked inheritance involves genes on the X (or Y) chromosome: • human females have 2 X chromosomes, hence 2 alleles for each X-linked gene • human males have 1 X chromosome, hence 1 allele for each X-linked gene ...
Unit #5 Direction Sheet - Sonoma Valley High School
Unit #5 Direction Sheet - Sonoma Valley High School

... B) Describe the components of Darwin’s theory of natural selection. Explain how Darwin’s natural selection differed from Lamarck’s theory of evolution. (Pages 297-301) C) Be able to explain Darwin’s phrase “Descent with modification”. (Pages 299-301) D) Describe several different types of evidence f ...
Natural Selection in Polygenic Traits
Natural Selection in Polygenic Traits

... Natural Selection in Polygenic Traits Most traits are polygenic, meaning they are coded for by more than one gene. Because many genes influence these traits, polygenic traits come in a range of phenotypes. For example, height is a polygenic trait. As a result, people come in a variety of sizes, rath ...
Neutral Theory
Neutral Theory

... The main power of neutral theory is it provides a theoretical expectation for genetic variation in the absence of selection. ...
Gene trees and species trees are not the same
Gene trees and species trees are not the same

... combined together, the total sequence emphatically confirmed the current consensus that, of these species, the humans and chimps have the most recent common ancestry (Box 1). When taken on their own, however, approximately 40% of the sequences gave different branching orders. Using the relationship ...
The Shifting Balance Theory of Evolution
The Shifting Balance Theory of Evolution

... is in gametic phase equilibrium). ...
1. Basic Genetic Concepts The Nature of Inheritance (Genetics)
1. Basic Genetic Concepts The Nature of Inheritance (Genetics)

... Sex-linked inheritance involves genes on the X (or Y) chromosome: ...
Biology 6 Practice Genetics Problems (chapter 15)
Biology 6 Practice Genetics Problems (chapter 15)

... If crossing over occurs 100% of the time between two linked genes, the result is 50% recombinant chromosomes in gametes and 50% parental chromosomes (as revealed by a test cross). This would be the case only if the genetic loci are at opposite ends of a chromosome, which produces the same basic outc ...
Document
Document

... killing small drosophilas or stop shooting hawks, the frequency of the given allele (of hawks) will return to the equilibrium value. This means that the population of sexual organisms under artificial or natural selection mostly behaves elastically rather than plastically. The existence of a so-call ...
(7) 381 PI SS and Altruism
(7) 381 PI SS and Altruism

... •  What of it? •  Selection acted on males differently than it acted on females •  Specifically, differences in parenting strategies cause differences in adaptations •  Sex that invests more: adaptations to survive and get resources for offspring •  Sex that invests less: adaptations to help them ge ...
WORKSHEET UNIT V
WORKSHEET UNIT V

... 9. Which of Mendel's principles states: if two contrasting forms a gene are present the dominant one will be expressed. 10. This type of microevolution involves a drastic decrease in population caused by a geologic catastrophe or over-harvesting by humans. 11. A sequence of nucleotides located at th ...
Parental Investment and Sexual Selection
Parental Investment and Sexual Selection

... • What of it? • Selection acted on males differently than it acted on females • Specifically, differences in parenting strategies cause differences in adaptations • Sex that invests more: adaptations to survive and get resources for offspring • Sex that invests less: adaptations to help them get as ...
Biology 12
Biology 12

... factors; or in response to the presence of a particular allele for another characteristic. Two main mechanisms are 1. DNA methylation 2. modifications of nucleosomal histones. (acetylation). These act to turn on or turn off genes. Many of these are activated by the environment. Some examples of dise ...
Phenotypic Determinants in Chronic airflow limitation
Phenotypic Determinants in Chronic airflow limitation

... But regional hypoxic vasoconstrictiojn will also preserve V/Q balance Hypoxic subjects more likely to develop cor pulmonale because of hypoxic vasoconstriction and increases in blood viscosity. But, hypoxaemia may represent a failure of vasoconstriction and hence a delay in elevation of pulmonary va ...
CSC598BIL675-2016
CSC598BIL675-2016

... not, then it is to do with something innocuous. Some methods are based on how common these variants are in families. ie shared ancestral variants and genetic linkage co-segregation Need pedigree haplotype information Mostly used in GWAS studies BEAGLE, GERMLINE, PLINK IBD, MERLIN ...
Heredity - bvsd.k12.pa.us
Heredity - bvsd.k12.pa.us

... 6. A ______________________________ trait covers up other traits. 7. In a Punnett square, a small letter (t) stands for a ______________________________ allele. ...
Mendelian Inheritance I 17 October, 2005 Text Chapter 14
Mendelian Inheritance I 17 October, 2005 Text Chapter 14

... inheritance of characters like flower color and seed shape by mating plants and observing the offspring. character: a heritable feature, like flower color. trait: a variant of a character, like purple or white flowers. ...
Darwin, Ahead of His Time, Is Still Influential
Darwin, Ahead of His Time, Is Still Influential

... Not only was Darwin correct on the central premises of his theory, but in several other still open issues his views also seem quite likely to prevail. His idea of how new species form was long eclipsed by Ernst Mayr’s view that a reproductive barrier like a mountain forces a species to split. But a ...
Study Material
Study Material

... As shown in Figure 24.3b, Nilsson-Ehle discovered that the colors fell into a 1:4:6:4:1 ratio He concluded that this species is diploid for two different genes that control hull color ...
< 1 ... 179 180 181 182 183 184 185 186 187 ... 377 >

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.
  • studyres.com © 2025
  • DMCA
  • Privacy
  • Terms
  • Report