Biological Change over Time

Biological Change
over Time
Ms. Cowman
Mutations: The Source of Genetic Variation
• All species exhibit genetic variation
• Mutations create new genes that provide a
continual supply of new genetic information
• Mutations may be:
NEUTRAL- provide no benefit or harm to the
HARMFUL- reduce the reproductive success of an
organism, do no accumulate over time
BENEFICIAL- produce a change in the individuals
phenotype that gives the individual an
advantage, accumulate over time
Mutations can have significant
Bacteria have developed resistance to antibiotics
are becoming more widespread as less-resistant
strains are killed off.
Viruses can mutate to become more virulent
(harmful), which can increase its ability to spread.
Selective Breeding: Artificial Selection of
• Domestication of Animals and Plants
Provide humans with the majority of our food
Formed the basis for the development of modern
• Domestication is the changing of members of a
species to suit human needs through controlled
captive breeding (Artificial Selection)
Examples of Artificial Selection
First species to be domesticated: Canis lupus, the wolf
Wild Sea Cabbage (1000’s of years) 7 vegetables
How does artificial selection work?
• The breeder picks seeds from the plants that
have the best flavour or largest fruit and sows
• The plants cross-pollinate each other
producing more fruit with the desired trait
Genetic Engineering
• Transfer beneficial genes from an individual of
one species to an individual of another species
• If successful, genetically modified individual is
mass produced
Power of Artificial Selection
• Production of individuals that exhibit traits that
are far beyond the natural variability present in
the original population
• Can reduce genetic diversity within a population
 Breeder favours only certain traits in a
population, then many alleles linked to other
versions of a particular characteristic are reduced
or eliminated
Implications for Natural Populations
What do we know about genetics?
- All species exhibit genetic variation
- Mutations produce heritable changes in
individuals, and these changes may be
beneficial, harmful, or neutral
- Some species, such as bacteria and insects, can
change over relatively short periods of time
- Some domesticated species have changed
dramatically under the influence of artificial
Related flashcards


17 cards

Population genetics

25 cards

Mitochondrial diseases

16 cards


23 cards


11 cards

Create Flashcards