Page 58 - CB1.3 Genetic Varation sciPAD

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58 CB 1.3 GENETIC VARIATION
GENETICS OF POPULATIONS
Migration
Migration is when animals move from one population to another. This movement of individuals
can lead to the transfer of alleles from one population to another, thereby impacting the genetic
variation within both source and destination populations.
When individuals from one population move to another, and successfully interbreed, they
introduce new alleles that may have been absent or less frequent in the receiving population. This
process, known as gene flow, can have several far-reaching consequences for genetic variation.
Firstly, increased genetic variation provides a buffer against environmental changes, making
the population more resilient. For example, new alleles might confer resistance to diseases, or
offer improved adaptability to different habitats. This enriches the gene pool, enhancing the
population's ability to survive and thrive under changing conditions.
Secondly, migration can dilute potentially harmful genetic traits or mutations that may exist within
a closed or isolated population. By mixing genes from different pools, detrimental alleles may
become less common, leading to a healthier, more robust population.
1. Use the diagram above and the word list provided to complete the following paragraphs.
separated - interbreed - migrate - dilute - move
variations - food - adaptations - increases - resistance
Migration is when animals from one population to another. Imagine
two populations of a particular species of bird that are
by a large mountain range. Over a long period of separation, they have developed
distinct genetic traits and due to their respective
environments.
Due to changing environmental conditions, some birds from one side of the mountain
range are able to to the other side. These birds bring their
unique genetic with them.
When they with the local population, new alleles are introduced.
Over time, this gene flow from one side of the mountain to the other
the genetic variation of that population.
This change can provide several advantages. For example, some of the new alleles may
offer to diseases or allow the birds to exploit new
sources. This gives the receiving population an evolutionary advantage.
Conversely, if the receiving population has harmful genetic traits, the new alleles could
these. This would benefit the overall health, adaptability and
survivability of the population.
Migrating population
Receiving population
The birds that leave are
emigrating from this
population
The birds that arrive
are immigrating to this
population
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