Heredity And Mendel's First Law

Overzicht

Why does a black bull crossed with a black cow sometimes throw a red calf. Why do two hornless goats occasionally produce a horned kid. The answer is not chance: it is heredity, the orderly passing of traits from parent to offspring, and it follows rules precise enough to predict on paper before a single mating takes place.

In this lesson you will learn the vocabulary breeders and examiners share: gene, allele, dominant, recessive, genotype and phenotype. You will then meet Mendel's first law, the law of segregation, and use it to solve monohybrid cross problems on real farm traits, coat colour and the polled condition, working out exactly what a planned mating is likely to produce.

Doelstellingen

  1. Define heredity
  2. State Mendel's first law of inheritance
  3. Explain the terms gene, allele, dominant and recessive
  4. Solve a simple monohybrid cross problem using Mendel's first law
  5. Explain the application of Mendel's first law to animal breeding

Lesnotitie

A herder in Sokoto mates a black bull with a black cow, and one calf is red. A goat farmer near Abeokuta mates two hornless does, and still gets a horned kid. Neither is unlucky: both outcomes are exactly what heredity predicts, and a breeder who understands the rule can say, before the mating, roughly how many of each type to expect.

Lesevaluatie

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  1. In cattle, black coat colour (B) is dominant over red coat colour (b). What is the phenotype of an animal with genotype Bb? A. Red B. Black C. A mixture of red and black D. Cannot be determined Answer: B
  2. The actual pair of alleles an animal carries for a gene is called its: A. Phenotype B. Genotype C. Allele D. Chromosome Answer: B
  3. Mendel's first law states that: A. Genes for different traits assort independently B. The two alleles of a gene separate during gamete formation C. Dominant alleles always outnumber recessive alleles D. Offspring always resemble one parent exactly Answer: B
  4. Two heterozygous polled goats (Pp) are mated. What phenotype ratio is expected among the offspring? A. 1 polled : 1 horned B. 1 polled : 3 horned C. 3 polled : 1 horned D. All polled Answer: C
  5. An animal carrying two identical alleles for a gene, such as BB, is described as: A. Heterozygous B. Homozygous C. Recessive D. Hybrid Answer: B

Aanbevolen Boeken

Introduction to Animal Science: Global, Biological, Social and Industry Perspectives
Introduction to Animal Science: Global, Biological, Social and Industry Perspectives
Ondertitel: Sixth edition
Uitgever: Pearson
Jaar: 2017
ISBN: 978-0-13-443605-0
Beschrijving: A comprehensive introduction to animal science covering anatomy and physiology, nutrition, genetics, reproduction, animal health and the major farm animal species and their production systems.
Small-scale Poultry Production: Technical Guide
Small-scale Poultry Production: Technical Guide
Uitgever: Food and Agriculture Organization of the United Nations
Jaar: 2004
ISBN: 978-92-5-105082-8
Beschrijving: An FAO Animal Production and Health Paper written by a Nigerian animal scientist, covering breeds, housing, feeding, incubation, disease control and marketing for small-scale poultry keepers in developing countries.
Tropical Animal Feeding: A Manual for Research Workers
Tropical Animal Feeding: A Manual for Research Workers
Uitgever: Food and Agriculture Organization of the United Nations
Jaar: 1995
ISBN: 978-92-5-103758-4
Beschrijving: An FAO Animal Production and Health Paper on the principles of ruminant and non-ruminant nutrition and the practical use of tropical feed resources, including crop residues and by-products, in sustainable livestock systems.