Question

• In Chapter 8, we learn about Mendel and his experiments that led to the Laws of Inheritance. After reading this chapter, summarize the following in your own words:
  • Difference between phenotype and genotype and how they are related.
  • How does a heterozygous organisms differ from a homozygous organism in terms of the alleles they contribute to the population?
  • Provide your best explanation for the law of segregation in 1-2 sentences.
• Understanding evolutionary relationships is an important element to understanding why organisms are placed in similar groups. In this step, you will be searching for a phylogenetic tree online, and making some observations related to the characteristics that group those organisms. You should use Chapter 12.1 as a guide. Here are the steps to follow for this section:
  • Pick a group of organisms that you would like to find a phylogenetic tree for from the following list: Plants, animals, vertebrates or invertebrates
  • In the google search bar, search for the following “plants (or whichever you pick), phylogenetic tree).
  • Click on “Images” below the Google search bar. You should see several trees that pop up. Find one that contains some characters (physical descriptions) so you can make some conclusions regarding the organisms.
  • Provide the following in your response:
    • A copy of the phylogenetic tree you found.
    • Write a summary of the characters or traits that are responsible for grouping organisms. Include an assessment of which organisms in the group are more closely related, as well as anything interesting or odd you found about the evolutionary relationships of the organisms.

Answer 1

Ans1 - To distinguish physical appearance from the genetic constitution, different terms are used in Genetics i.e., genotype and phenotype.

Genotype is defined as the genetic constitution of an individual for a particular character or trait. The genotype of an individual is usually expressed by a symbol e.g. TT, tt, or Tt etc.

The phenotype is defined as the physical appearance of an individual for any particular trait.

Example-tall or short. Phenotype of an individual is dependent on its genetic constitution.

Ans 2- Homozygous and Heterozygous

Each parent (diploid) has two alleles for a trait, they may be:

Homozygous, indicating they possess two identical alleles for a trait.

· Homozygous dominant genotypes possess two dominant alleles for a trait (TT)

· Homozygous recessive genotypes processes two recessive alleles for a trait (tt)

Heterozygous genotype possesses one of each allele for a particular trait (Tt).

Ans3- On the basis of monohybrid cross (cross involving only one trait), Mendel formulated the law of segregation. This law states that each individual processes two factors (later termed as genes) for a particular character. At the time of formation of gametes each number of the pairs of genes separate from each other so that each gamete carries only one factor gene i.e. gametes are always pure (law of purity of gametes.). It also explains that heredity factors are discrete and don't blend when present together