Variation and Evolution Flashcards
What is a species?
A collection of organisms capable of interbreeding that produce fertile offspring
This definition highlights the reproductive capability of species.
Define variation in the context of population.
Differences within a population
Variation is essential for the process of evolution.
What is classification in biology?
Grouping organisms based on specific characteristics
Classification helps in organizing and understanding biodiversity.
List the causes of variation.
- Sexual reproduction
- Mutations: Change in the amount or the structure of DNA
Both processes contribute to genetic diversity within populations.
What are mutagens?
Causes of mutation
Examples include chemicals, radiation, and viruses.
Define gene/point mutations.
A change in a single gene, e.g. haemophilia
These mutations can have significant effects on an organism’s traits.
What are chromosome mutations?
A change in the number or structure of one or more chromosomes, e.g. down syndrome
These mutations can lead to various genetic disorders.
What is evolution?
Genetic changes in a population over a period of time and selected for due to changes in the environment
Evolution is a fundamental concept in biology explaining how species adapt over time.
Who presented the theory of natural selection?
Darwin and Wallace
Their work laid the foundation for modern evolutionary biology.
What observation did Darwin and Wallace make regarding population sizes?
Large numbers of offspring produced, but the population size stays the same overall
This observation led to insights about competition and survival.
What is the explanation for the competition between organisms?
There is competition between organisms for a limited resource
This competition drives natural selection.
What does ‘survival of the fittest’ mean?
The better adapted organisms for competition survive, while the less adapted organisms die
This phrase encapsulates the essence of natural selection.
What happens to adapted organisms over time?
They interbreed and pass on this adaptation to their offspring
This leads to adaptations becoming more common in the population.
What evidence supports the theory of evolution?
Fossils show differences when compared with modern organisms
Fossils provide a historical record of changes in species over time.
