Variation & Evolution
This lesson covers:
- What 'variation' is
- How both genes and the environment can contribute to variation
- The difference between 'continuous variation' and 'discontinuous variation'
- What 'survival of the fittest', 'natural selection', and 'evolution' mean
- Who Charles Darwin was
- How evolution works
What does the term 'phenotype' mean?
The combination of alleles that an organism has
One of the different forms of a gene
The observable characteristics of an organism
|
Differences in the characteristics of individuals within a population is called .
|
Which two factors contribute to the variation between organisms?
|
A change in the DNA code is called a .
|
What factor(s) are involved in determining body mass?
Both genetic factors and environmental factors
Genetic factors only
Environmental factors only
|
Which of the following are determined entirely by genetic factors?
(Select all that apply)
Biological sex (male or female)
Natural eye colour
Skin colour
Height
|
Continuous and discontinuous variation
- Characteristics within a species can either show either 'continuous variation', or 'discontinuous variation'
- Continuous variation is where the characteristic changes gradually over a range of values, such as height, body mass, and skin colour. These characteristics are usefully influences by multiple genes (polygenic).
- Discontinuous (discrete) variation is where the characteristic has distinct forms, with no overlap. For example, eye colour is discontinuous because you have either blue, green, or brown eyes. These characteristics are usually only influenced by one or two genes.
Which of the following characteristics show continuous variation?
(Select all that apply)
Strength
Blood group (A, B, or AB)
Hair colour
Eye colour
|
A change in the genetical material of an organism is called a .
|
Which statement about mutations is true?
They never have any affect on the organism
They are always advantageous
They are always harmful
They generally have no effect, but are occasionally harmful, and very occasionally advantageous
|
What does the phrase 'survival of the fittest' mean?
The individuals with the most favourable characteristics are most likely to survive
Certain individuals are selected by humans to reproduce
Over long periods of time, one population of organisms may become a new species
|
___________ is the process by which the inherited characteristics of a population change over time due to natural selection. In some cases this may result in the formation of a new species.
|
Who is credited with developing and proposing the theory of evolution?
Charles Babbage
Charles Darwin
Jean-Baptiste Lamarck
|
Which of the following provide evidence for the theory of evolution?
(Select all that apply)
The fact that variation is due to genes and the environment
The spread of antibiotic resistance
The fact that the human body is so complex
Fossil records
|
Describe a series of events that might result in zebras evolving to run more quickly.
|
Speciation is the evolutionary process by which populations evolve to become distinct .
|