Ch.24 - Evolution of PopulationsWorksheetSee all chapters
All Chapters
Ch.1 - Introduction to Biology
Ch.2 - Chemistry
Ch.3 - Water
Ch.4 - Carbon
Ch.5 - Biological Molecules
Ch.6 - Cells
Ch.7 - The Membrane
Ch.8 - Energy and Metabolism
Ch.9 - Respiration
Ch.10 - Photosynthesis
Ch.11 - Cell Signaling
Ch.12 - Cell Division
Ch.13 - Meiosis
Ch.14 - Mendelian Genetics
Ch.15 - Chromosomal Theory of Inheritance
Ch.16 - DNA Synthesis
Ch.17 - Gene Expression
Ch.18 - Regulation of Expression
Ch.19 - Viruses
Ch.20 - Biotechnology
Ch.21 - Genomics
Ch.22 - Development
Ch.23 - Evolution by Natural Selection
Ch.24 - Evolution of Populations
Ch.25 - Speciation
Ch.26 - History of Life on Earth
Ch.27 - Phylogeny
Ch.28 - Prokaryotes
Ch.29 - Protists
Ch.30 - Plants
Ch.31 - Fungi
Ch.32 - Overview of Animals
Ch.33 - Invertebrates
Ch.34 - Vertebrates
Ch.35 - Plant Anatomy
Ch.36 - Vascular Plant Transport
Ch.37 - Soil
Ch.38 - Plant Reproduction
Ch.39 - Plant Sensation and Response
Ch.40 - Animal Form and Function
Ch.41 - Digestive System
Ch.42 - Circulatory System
Ch.43 - Immune System
Ch.44 - Osmoregulation and Excretion
Ch.45 - Endocrine System
Ch.46 - Animal Reproduction
Ch.47 - Nervous System
Ch.48 - Sensory Systems
Ch.49 - Muscle Systems
Ch.50 - Ecology
Ch.51 - Animal Behavior
Ch.52 - Population Ecology
Ch.53 - Community Ecology
Ch.54 - Ecosystems
Ch.55 - Conservation Biology

Solution: A new kind of geranium is produced that develops only red or yellow flowers. Assume that flower color is controlled by a single-gene locus and that the red allele (R) is dominant to the yellow allele

Problem

A new kind of geranium is produced that develops only red or yellow flowers. Assume that flower color is controlled by a single-gene locus and that the red allele (R) is dominant to the yellow allele (r). A random sample of 1000 geraniums from a large cultivated field yields 800 red flowers and 200 yellow flowers. What is the frequency of the red alleles in this field population?

A. red allele frequency = 0.847 

B. red allele frequency = 0.55

C. red allele frequency = 0.82

D. red allele frequency = 0.61

E. red allele frequency = 0.153

Solution

The given problem shows that the phenotypic frequency is 0.8 for the dominant trait and 0.2 for the recessive trait. From the given, we can compute for the allele frequencies only by assuming that the population follows Hardy-Weinberg equilibrium. In a Hardy-Weinberg equilibrium, the frequency of the dominant allele can be represented by p, and the frequency of the recessive allele can be represented by q. For a trait that only has two alleles, p + q = 1. Furthermore, these values can be used to compute for the genotypic frequencies: p2 is for the homozygous dominant, 2pq is for the heterozygotes and q2 for the homozygous recessive.

View the complete written solution...