Page 49 - CB1.3 Genetic Varation sciPAD

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CB 1.3 GENETIC VARIATION
GENETICS OF POPULATIONS
Introduction to Population Genetics
Population genetics is a field of genetics that deals with the genetic makeup of populations and
how they change over time. This field aims to understand the distribution and frequency of alleles
(variations of a gene) in a given population, and how these factors are influenced by various
forces such as:
•
Natural Selection: The process where organisms with advantageous traits are more likely to
survive and reproduce, thereby passing on those traits to the next generation.
•
Mutation: The creation of new alleles through errors in DNA replication.
•
Small Population Size: Small populations are often more susceptible to environmental changes
due to reduced genetic variation, which limits the population’s ability to adapt.
•
Gene Flow: The exchange of genes between different populations, usually by migration,
which can introduce new alleles and alter genetic variation.
Population genetics is instrumental in various fields such as ecology, evolution and conservation
biology. It can help us predict how populations will evolve in the future, which is crucial for efforts
like conservation and the management of endangered species. Population genetics also has
applications in medicine for understanding the spread of genetic diseases and the development
of resistance to drugs.
Archaeological evidence indicates kea were once prevalent in New Zealand’s lowland forests before
Polynesian and European settlers arrived. Now, they are mainly found in alpine regions on the South Island’s
west coast, largely due to the impact of mammalian predators, including humans. Understanding the genetics
of these endangered birds is crucial for conservation efforts aimed at ensuring their long-term survival.
1. Outline the primary reason biologists study population genetics. 


2. Define the term ‘allele’. 

3. List the four main forces that influence the distribution and frequency of alleles in a
population.
(a) 
(b) 
(c) 
(d) 
4. Describe how mutation can introduce new alleles into a population. 


5. In conservation biology, why is understanding population genetics crucial for the
management of endangered species? 


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