Biology Genetics & Evolution 1

Question 1

What is the basic unit of heredity?

Accepted Answer

Genes

Answer

Genes are the basic units of heredity, consisting of specific sequences of DNA that code for particular traits or functions. They are passed down from parents to offspring, carrying the instructions that determine an organism's characteristics, from physical appearance to metabolic processes. This makes genes fundamental to understanding how traits are inherited and expressed across generations.

Question 2

What is natural selection?

Accepted Answer

The process where advantageous traits become more common

Answer

Natural selection is a key mechanism of evolution, described by Charles Darwin. It describes how organisms better adapted to their environment tend to survive and produce more offspring. Over generations, individuals with advantageous heritable traits are more likely to reproduce, leading to these traits becoming more prevalent in the population, thus driving evolutionary change.

Question 3

What is a mutation?

Accepted Answer

A change in DNA sequence

Answer

A mutation is a permanent alteration in the DNA sequence that makes up a gene or chromosome. These changes can occur spontaneously during DNA replication or be induced by environmental factors like radiation. Mutations are the ultimate source of genetic variation, which is essential for evolution, although they can also be harmful or neutral in their effects on an organism.

Question 4

What does genetic drift refer to?

Accepted Answer

Random changes in allele frequency

Answer

Genetic drift refers to the random fluctuations in the frequency of alleles (different forms of a gene) in a population, particularly in small populations. Unlike natural selection, which is directional, genetic drift is a chance event that can lead to the loss or fixation of certain alleles, regardless of their adaptive value. It is a significant evolutionary force, especially in isolated or small populations.

Question 5

What is the role of DNA in heredity?

Accepted Answer

It stores genetic instructions for inheritance

Answer

DNA (deoxyribonucleic acid) is the molecule that carries the genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms. It stores the complete blueprint for an organism's traits and functions, which is then passed from one generation to the next. This ensures the inheritance of characteristics and the continuity of life.

Biology Practice Test

Biology Practice Test

Biology Genetics & Evolution 1