A3.1 Diversity of organisms Flashcards
Define variation in biology.
Variation refers to the differences that exist between organisms, such as in visual appearance, behaviour, or biochemistry.
What are the two main causes of variation?
The two main causes of variation are genetic factors and environmental factors.
How is genetic variation generated?
Genetic variation is generated when mutations occur and when alleles are combined in different ways during sexual reproduction.
True or False?
Members of the same species are genetically identical.
False.
While members of a species have a similar genetic makeup, different individuals have different combinations of alleles.
What is discontinuous variation?
Discontinuous variation is when characteristics fall into distinct categories, such as black fur vs brown fur, or human blood type.
What is continuous variation?
Continuous variation means that characteristics can be measured incrementally on a scale, e.g. height.
Define taxonomy.
Taxonomy is the science of classification, and scientists working in this field are called taxonomists.
Who is considered the ‘father of taxonomy’ and why?
Carl Linnaeus is considered the ‘father of taxonomy’ because he developed the method of naming species that is used by scientists worldwide today.
What is the binomial system of nomenclature?
The binomial system of nomenclature is the biological system of naming species using a two-part Latin name, consisting of the genus and species name.
How should binomial names be written when typed?
When typed, binomial names should appear in italics, e.g. Patella vulgata.
State the biological species concept.
The biological species concept states that a species is a group of organisms that can interbreed to produce fertile offspring.
What is a limitation of the biological species concept?
Limitations might include:
The species concept cannot be applied to organisms that reproduce asexually, such as bacteria.
Hybrid ‘species’ can be fertile on rare occasions.
Extinct organisms are not able to breed.
Define speciation.
Speciation is the process by which one species gives rise to two or more new species.
How can isolation lead to speciation?
Isolation can lead to speciation when a population becomes separated from other populations of the same species, preventing gene flow and allowing natural selection or genetic drift to act differently on each population.
True or False?
Speciation occurs rapidly.
False.
Speciation occurs over very long time periods, with differences between isolated populations accumulating incrementally.
