A4.1 Evolution and speciation Flashcards
Which of the following is the most accurate definition of evolution?
A. The formation of two species from a single species.
B. The change in populations caused by mutation.
C. The change in the heritable characteristics of a population.
D. The change in the physical characteristics of a population.
C. The change in the heritable characteristics of a population.
There are many different domesticated breeds of cattle descended from the wild ox about 10,500 years ago. What is the term that describes the formation of new breeds of farmed cattle?
A. Inbreeding.
B. Selective breeding.
C. Natural selection.
D. Speciation.
B. Selective breeding.
The lion (Panthera leo) and the tiger (Panthera tigris) are believed to have evolved from a recent common ancestor. What is the name for this type of evolution?
A. Isolation.
B. Polyploidy.
C. Survival of the fittest.
D. Speciation.
D. Speciation.
Which of the following is not regarded as evidence for evolution by natural selection?
A. Selective breeding.
B. Homologous structures.
C. Analogous structures.
D. DNA base sequences.
C. Analogous structures.
The image is of a fossil of Magallena gryphoides from Crete, Greece from the Early Tortonian Age approximately 9 million years bp (before present).
This fossil organism is related to present day oysters (Ostreidia family).
The graph shows the relationship between the length and the width of the fossilised shell (courtesy Nikos Marangos).
The uncertainty of measurement is estimated at 0.01mm. Suggest a measuring instrument that could have been used to achieve this degree of accuracy. (1 mark)
Use calipers, laser measurement (not a a simple ruler)
The image is of a fossil of Magallena gryphoides from Crete, Greece from the Early Tortonian Age approximately 9 million years bp (before present).
This fossil organism is related to present day oysters (Ostreidia family).
The graph shows the relationship between the length and the width of the fossilised shell (courtesy Nikos Marangos).
List two other uncertainties that would have to be considered in evaluating the data in this investigation.
Damage to the fossil during extraction / There could be an incomplete fossil.
Age estimation (of the fossil). All the fossils measured may not have been of the same age.
Other relevant absolute or systematic uncertainty.
The image is of a fossil of Magallena gryphoides from Crete, Greece from the Early Tortonian Age approximately 9 million years bp (before present).
This fossil organism is related to present day oysters (Ostreidia family).
The graph shows the relationship between the length and the width of the fossilised shell (courtesy Nikos Marangos).
Describe the relationship between the length of the shells and the width of the shells.
There is a positive correlation between length and width.
The correlation is weak/large amount of variation in the data.
The image is of a fossil of Magallena gryphoides from Crete, Greece from the Early Tortonian Age approximately 9 million years bp (before present).
This fossil organism is related to present day oysters (Ostreidia family).
The graph shows the relationship between the length and the width of the fossilised shell (courtesy Nikos Marangos).
The dimensions of the largest shell are 451.90mm length and 159.62mm width.
Deduce whether this specimen could be considered as an outlier in the data.
Could be considered as an outlier – much larger than other specimens.
Should not be considered an outlier – very close to the line of best fit.
(Note: reason required)
The image is of a fossil of Magallena gryphoides from Crete, Greece from the Early Tortonian Age approximately 9 million years bp (before present).
This fossil organism is related to present day oysters (Ostreidia family).
The graph shows the relationship between the length and the width of the fossilised shell (courtesy Nikos Marangos).
The dimensions of the largest shell are 451.90mm length and 159.62mm width.
Suggest why fossils could be regarded as evidence of evolution by natural selection.
Fossils give us data on species that are no longer living.
We can estimate the age that fossils were living.
A sequence of fossils can demonstrate (gradual) changes in features/characteristics in a series of species that are evolving.
Explain why analysis of base sequences of DNA can provide evidence of biological evolution from a common ancestor.
Some base sequences are conserved and vary very little between species giving powerful evidence of common ancestry.
DNA analysis finds many similarities in base sequences between closely related organisms and fewer similarities between less closely related species.
The gradual divergence of DNA base sequences in a range of species if evidence of evolutionary pathways.
Note: only 2 points needed for 2 marks
Distinguish between analogous and homologous structures, giving an example of each
type of structure.
(4 marks)
Homologous structures (may) have different functions and analogous have the same function.
Homologous structures have similar structures and analogous have different structures.
Analogous structures arise from a different evolutionary pathway and homologous arises from an identical evolutionary pathway.
One example of each type of structure (maximum 1 mark for each)
Outline the process that allows new species to evolve from a single species in the same habitat to avoid competition for resources. (4 marks)
Adaptive radiation allows the formation of separate species from a single species in the same habitat.
This is a process of sympatic speciation.
Adaptation to different niches by groups of organisms to avoid competition, causes each group to evolve different features or behaviour by natural selection.
Differences in, body shape, courtship behaviour (mate selection), or feeding behaviour can result in reproductive isolation of these groups.
(Adaptive radiation) Increases species diversity within a habitat as all the species occupy different niches in the same habitat.
Credit could be given for a named example, e.g. Cichlids of lake Malawi.
Note: only 4 points needed for 4 marks.
Explain how reproductive isolation can maintain the divergent evolution of two separate species occupying the same habitat.
(4 marks)
Reproductive isolation prevents the two species from interbreeding.
Differences in courtship behaviour means that females are not attracted to males or the other group, and vice versa.
A chromosome change in one group can lead to hybrid sterility, so that if members of the two groups do interbreed, the hybrids are not fertile.
If the separate species are reproductively isolated, then there will be a gradual accumulation of differences in the genome of each species.
The gene pool of each species will become more different over time, resulting in divergent evolution.
Credit can be given for a second relevant example of reproductive isolation, such as gamete incompatibility/breeding season differences etc.
Note: only 4 points needed for 4 marks.
