There are different types of evidence which support the theory of evolution, from fossils to selective breeding. This topic covers a range of evidence and some of the concepts related to inheritance, natural selection and evolution.
Learn and test your biological vocabulary for 5.1 Evidence for evolution using these flashcards.
Revision summary list for 5.1 Evidence for evolution
- A change in the heritable characteristics of a species is evolution.
- Evidence for evolution comes from
- the fossil record.
- Selective breeding of domesticated animals
- "Adaptive radiation" can explain similar structures with different functions.
- Isolated populations can produce separate species by divergent evolution.
- Continuous variation across the geographical range of related populations matches the concept of gradual divergence.
Skills (can you ....)
- Describe how the dark bark leads to the development of melanistic insects in polluted areas.
- Compare and contrast the pentadactyl limb of mammals, birds, amphibians and reptiles.
- Describe how each limb structure is adapted to each different method of locomotion.
Mindmaps
These diagram summaries cover the main sections of topic 4.3 Carbon cycle.
Study them and draw your own list or concept map, from memory if you can.
Exam style question about pentadactyl limbs as evidence of evolution
The question below, requires an understanding of the structure of the pentadactyl limb and the differences and adaptations which can be found in different animals. In this case the examples are birds and humans.
Answer the question on paper and then compare your answer to the model answer.
Compare and contrast the pentadactyl limb of mammals and birds. [4]
- Include similarities in structure
- Mention differences in specific elements
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Describe how the structure of the wing and hand is adapted to each different function [2]
- Try to link structure and function in each point of your answers?
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Explain how the existence of these structures in birds and mammals provides evidence supporting the theory of evolution. [3]
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Click the + icon to see a model answer.
Model answer
The skill of this answer is to ensure that the points make logical connections between the two species.
Compare and contrast the pentadactyl limb of mammals and birds. [4]
Similarities
- The bird wing and the human arm both have a humerus, ulna and a radius bone.
- Both limbs also have several wrist bones
- They are an example of homologous structures - evolving from a single origin.
Differences
- There are only three "finger bones" in the bird wing and five in the human hand.
- The finger bones are longer in the bird wing than in the human hand.
Describe how the structure of the wing and hand is adapted to each different function. [2]
The skill in this answer is to link a structure to it's function
- The wrist bones of birds have long shapes, allowing the attachment of feathers.
- The position of the thumb opposite the other fingers on the human hand allow it to hold tools
Explain how the existence of these structures in birds and mammals provides evidence supporting the theory of evolution. [3]
This answer requires knowledge beyond the data provided.
The pentadactyl limb is found in Birds Mammals as well as reptiles and amphibians
They all share the same organisation of bones even though these animals use a wide variety of methods of locomotion. This is known as 'adaptive radiation'.
The simplest explanation of the existence of this bone arrangement in so many different animals is that it evolved once in history in a common ancestor of all the animals. These animals have since evolved by divergent evolution to use the structures in a variety of ways.
It would be very unlikely that two separate evolutionary processes would arrive at the same structure as complex as a pentadactyl limb.
Extra exam question about adaptive radiation (evolution). Click to open it .
The question below, requires an understanding of adaptive radiation, but also knowledge of the finches of the Galapagos islands. Explaining how the finches provides evidence for the process of adaptive radiation is worth thinking through and practising.
Answer the question on paper and then compare your answer to the model answer.
The diagram below, drawn by Darwin, illustrates the size and shape of finch species in the Galapagos islands.
Explain how the shape of beaks in Galapagos finches provides evidence for adaptive radiation. [4]
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Model answer
Explain how the shape of beaks in Galapagos finches provides evidence for adaptive radiation. [4]
Adaptive radiation is the development of one ancestor species into several different forms as each one separately adapts to the environment in each of the different, new, unoccupied ecological niches.
Darwin discovered many different forms of closely related Galapagos finches on the islands of the archipelago, the Galapagos islands..
The size and shape of their beaks which was most noticeably different and all these different forms of beak supported the idea of adaptive radiation.
Each species had had separately evolved from a single species of ancestor finch. Each island having different environmental conditions had resulted in the finches on that island evolving in slightly different ways to have beaks of different shapes.
Extra exam question on speciation - - - click to open.
Speciation is the evolution of two distinct species from a common ancestor.
Answer the question on paper and then compare your answer to the model answer.
Outline how one population of a species can evolve into two separate species. (5 marks).
Hint: Outline requires the main points. The word "speciation" is not in the question and so will gain credit.
Click on the "+" icon to see a model answer.
Model answer
Examples of speciation may help you to answer the question.
Outline how one population of a species can evolve into two separate species. (5 marks).
- Speciation is the evolution of two or more species from a common ancestor.
- Speciation occurs when two populations are isolated from each other.
- By geographic or behavioural factors.
- The two populations are not able to interbreed.
- Different selection pressures in the different environments can favour different characteristics.
- The heritable characteristics of the two populations diverge as the genomes change.
- Speciation can then occur when the two species evolve different traits and have sufficient variation to be considered as different species.
Examiner hint: Speciation requires isolation and different selection pressures as if the two groups interbreed they will not become separate species.
Multiple choice questions
This is a self marking quiz containing questions covering the topic outlined above.
Try the questions to check
your understanding.
START QUIZ!
Which of the following statements is not true about Evolution?
It is learned by animals during their lifetime.
It happens at the species level.
It's a gradual cumulative change.
It concerns characteristics which can be inherited.
"A change in the heritable characteristics of a species" is evolution.
Most frequently this is a gradual cumulative change.
Changes to individual organisms during their lifetime are not evolution, as the change has to be heritable.
Evolution occurs a the species level because individuals survive or die which changes the composition of the members of the species.
Which of the points below provide evidence in support of evolution?
The fossil record.
Selective breeding of food crops.
The wings of birds and bats
Radiation studies
I, and II
All of the points
I and IV
I and III
Evidence for evolution in this list comes from;
- The fossil record.
- Selective breeding of food crops and domesticated animals.
What might be expected to happen if two populations of a species of snail are separated by a river which has very different environmental conditions on each bank, for example a woodland and a golf course?
Divergent evolution.
Interbreeding of the two population.
One population will become better adapted to the environment.
Convergent evolution.
If the are different selection pressures in the two environments, then snails will be affected by different natural selection. This is divergent selection.
Lake Malawi has a surface area of almost 30 000 km2 and is home to 1000 species of Cichlid fish.
The diagram of Cichlid fish varieties illustrates a continuous variation in their features across the geographical range of the lake.
It is understood that all but five species are descendants of a single original colonist species?
What is the name of the process which forms this sort diversity?
Evolution.
Gradual production of new species.
Adaptive radiation.
Natural selection.
Continuous variation across the geographical range of related populations matches the concept of gradual divergence.
The image below shows adaptations in the wings of modern insects.
There is evidence that ancestors of all these insects had two pairs of wings.
What is the biological term for structures like these?
Equivalent.
Homologous.
Vestigial
Equivalent
All the insects share the feature of having 2 pairs of 'wing-like' structures although there are differences in each animal.
This suggests that they all shared a common ancestor, with 2 pairs of wings.
What is the best description of selective breeding?
A farmer selects sheep with the highest quality wool at a market.
A zoologist in a safari park puts animals together for breeding to increase genetic diversity.
A dog breeder selects the animals with preferred features for his breeding programme.
A pet owner keeps carefully selected aquarium fish so there are no predators in the tank.
Selective breeding provides evidence for evolution because it shows that when a breeder chooses the animals for the breeding programme which have specific features, the offspring have more of these features.
What natural process causes the increase in frequence of the melanistic form of the Peppered moth if pollution causes the vegetation it lives on to be covered in smoke and become darker?
Selective breeding
Adaptive radiation
Natural selection
Disruptive selection
Natural selection causes an increase in the number of dark moths because the birds which eat the moths cannot see the dark forms so easily, as they have better camouflage in polluted environments.
This is a second self marking quiz containing different questions covering the topic outlined above in a slightly different way.
START QUIZ!
Which is the most compelling evidence provided by fossils in support of evolution?
They can be dated which shows their origin.
They are found in sedimentary rocks.
They document the existence of extinct organisms that show a relationship to present day species.
They are extinct species which end an evolutionary line.
All the answers have some relevance but the most compelling is that they document the existence of extinct organisms that show a relationship to present day species, often illustrating the cumulative changes which have occurred.
Which of the following best describes homologous structures?
They are identical in structure.
They are identical in function.
They are derived from single origin in a common ancestor.
They are identical in structure and function.
Homologous structures evolved from a common ancestor and have a similar structure but this structure may be modified to adapted to a different function.
Which of these statements best describes the structure and function of homologous characteristics?
Similar in structure and have the same function.
Identical in structure and vary in function.
Similar in structure and may vary in function.
Animal legs, arms, wings and claws are homologous structures.
Homologous structures have a similar structure but not identical structures, and this allows them to adapt to new functions. Legs and arms of animals are sometimes examples of homologous structures but, not always, e.g. insect legs and human legs are not homologous.
Adaptive radiation is shown by organisms evolving in different environments. What observable patterns does this process lead to?
Different types of limbs in organisms.
Common features in unrelated species.
A range of different adaptations of a feature in related species.
Very similar organisms with different forms of locomotion.
Adaptive radiation occurs when different selection pressures lead to the evolution of a range of different adaptations. This may occur at first in a single species but will eventually be seen in several related species. They may be in different isolated locations or in organisms exploiting different niches in a single environment.
Which two factors drive the process of adaptive radiation.
Random selection of mates in reproduction and different behaviour.
Random genetic mutations and new forms of DNA appearing.
Random genetic mutations and different selection pressures.
New forms of locomotion and different reproductive behaviour.
Adaptive radiation occurs when different selection pressures lead to the evolution of one or more species which are exploiting different niches in an environment. Mutations bring about new alleles in several genes and different selection pressures in each niche lead to the natural selection to favour different adaptations.
The existence of different breeds of domestic dog is due to which of the following?
Artificial selection.
A Mutation.
Natural selection.
Random mating.
Dog breeds are developed by humans artificially selecting certain traits in dogs and breeding only the animals with these desired traits.
Which of the following best describes evolution?
A change in the appearance of a species.
A change in the heritable characteristics of a species over time.
The formation of new species.
Random changes in the genes of a species.
As evolution occurs, the heritable characteristics (genes) in the gene pool of a species change to those which are the most successful for survival.
Which of the following must happen to allow two new species to arise from a single species?
I Separation of the original species into two groups
II Interbreeding between the groups
III Different mutations in the two groups
IV Reproductive isolation between the two groups
I only.
II and III only.
I, III, IV only.
All of the above, I, II, III, and IV.
For two groups of one species to form two species, they must be reproductively isolated, so they cannot interbreed and then different mutations will allow different genetic variation in each of the isolated populations, leading to adaptation to their respective environments and phenotypic differences between the groups.
Drag and drop activities
Test your ability to construct biological explanations using the drag and drop questions below.
The acceptance of a scientific theory requires evidence. Fossils are one piece of evidence for the scientific theory of evolution.
Drag and drop the correct word or phrase to outline the evidence for evolution provided by fossils.
1
present day long time scales complexity sequences living hundreds of years internal organs hard preserved shells extinct single-celled
Fossils are the remains of previously living organisms. Bones and are commonly fossilised as they are and durable by nature.
Fossils provide evidence for evolution in several ways:
- They demonstrate the existence of organisms that are not now .
- Fossil show gradual evolution of species.
- Fossils provide evidence of evolution over .
- Fossils of now species can be linked to species.
- The sequence in time of the fossil record equates with the increasing of living organisms from to multicellular organisms.
Fossils are good evidence of the evolution of life over a long time scale.