Download GRADE 11A: Biology 6 Evolution by natural selection UNIT 11AB.6

GRADE 11A: Biology 6
UNIT 11AB.6
4 hours
Evolution by natural selection
About this unit
Previous learning
Resources
This unit is the sixth of eight units on biology for
Grade 11 advanced.
To meet the expectations of this unit, students should already know that
species are clustered into groups. They should know about the hierarchy of
classification and the key features of the kingdoms and main phyla of
animals and plants
The main resources needed for this unit are:
The unit is designed to guide your planning and
teaching of biology lessons. It provides a link
between the standards for science and your
lesson plans.
The teaching and learning activities should help
you to plan the content and pace of lessons.
Adapt the ideas to meet your students’ needs.
For extension or consolidation activities, look at
the scheme of work for Grade 12A and
Grade 10A.
You can also supplement the activities with
appropriate tasks and exercises from your
school’s textbooks and other resources.
Introduce the unit to students by summarising
what they will learn and how this builds on earlier
work. Review the unit at the end, drawing out the
main learning points, links to other work and real
world applications.
Expectations
By the end of the unit, students understand that predation, disease and
competition result in differential survival rates and reproduction, and that
organisms with a selective advantage are more likely to survive and pass on
genes to the next generation, that natural selection and isolation can lead to
new species, and that evolution over a long period of time has given rise to
the diversity of living organisms.
• overhead projector (OHP), whiteboard
• pictures of a variety of organisms
• videos of wildlife in an African reserve and on the Galapagos Islands
• Internet access
Key vocabulary and technical terms
Students should understand, use and spell correctly:
• evolution by natural selection, speciation
• palaeontology
Students who progress further know how some organisms are structurally
and physiologically adapted to their environment and distinguish between
acclimatisation and adaptation. They understand ecological colonisation and
succession.
249 | Qatar science scheme of work | Grade 11 advanced | Unit 11AB.6 | Biology 6
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Objectives for the unit
4 hours
SUPPORTING STANDARDS
the survival and reproduction of the strongest individuals and that this
natural selection allows the inheritance of their characteristics.
Natural selection
of individuals
10A.14.1 Understand the term species, know
Natural selection,
speciation and
diversity
Adaptation to
environment
11A15.2 Know that natural selection and breeding isolation can lead to speciation.
that species can be placed in groups
with shared features, and that the
groupings of kingdom, phylum, class,
order, family, genus and species
form a hierarchy of classification.
10A.14.2 Know the distinguishing features of
1 hour
CORE STANDARDS
Grade11 standards
11A.15.1 Know that predation, disease and competition within a population result in
1 hour
2 hours
Unit 11AB.6
the five kingdoms: Prokaryotae,
Fungi, Protoctista, Plantae and
Animalia.
10A.14.3 Use knowledge of the key features of
the major phyla of animals and plants
to recognise a typical member.
EXTENSION STANDARDS
12A.13.1 Explain examples of structural and
physiological adaptations of animals to
their environment.
12A.13.2 Distinguish between the permanent
adaptation of an organism to its
normal environment and the
temporary acclimatisation of a visitor.
11A.15.3 Explain how natural selection and evolution over a long period of time have
resulted in a great diversity of forms among living organisms.
11A.15.4 Give examples and explanations of how organisms are adapted to survive
in particular environmental conditions.
250 | Qatar science scheme of work | Grade 11 advanced | Unit 11AB.6 | Biology 6
12A.14.3 Describe the progression of the
development of an ecological
community from primary colonisation
to climax community.
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Activities
Unit 11AB.6
Objectives
Possible teaching activities
1 hour
Introduce natural selection by using familiar examples so that students become immediately
involved. Animals are the most easily observed and familiar organisms for most students. Ask
them, for example:
Natural selection of
individuals
Know that predation, disease
and competition within a
population result in the
survival and reproduction of
the strongest individuals and
that this natural selection
allows the inheritance of their
characteristics.
Notes
School resources
• Have you seen a duck nesting in the local park or pond?
• How many young did it produce?
• What has happened to those young birds?
• Why aren’t we overrun with ducks when they reproduce so many young?
Alternatively, show a video of predators and prey in an African wildlife reserve. Discuss the role
of predators. Make sure students appreciate that predation is essential in maintaining stable
populations of the strongest individuals.
Reinforce previous knowledge on animal populations, including predator–prey interactions as
well as inter- and intra-specific competition for food and space, by using further examples.
Ask students how territorial behaviour helps natural selection. The territorial behaviour of
animals, for example, deprives the weaker individuals of food and a suitable breeding location,
leading to the loss of these genes from the gene pool.
Ask students how disease helps natural selection. Tell them about rabbits and myxomatosis.
Explain that 1% of the rabbits survived the disease – these were the resistant rabbits and so
they became the naturally selected individuals for the future generations.
Get students to find out about the work of Darwin and Wallace from the library. Discuss their
findings in class and then ask them to write a report on the theory of evolution by natural
selection.
2 hours
Natural selection,
speciation and diversity
Know that natural selection
and breeding isolation can
lead to speciation.
Explain how natural selection
and evolution over a long
period of time have resulted
in a great diversity of forms
among living organisms.
Having introduced Darwin and Wallace in the earlier discussion, use this to provide a starting
point to discuss how new species have evolved.
Show students a video of the Galapagos Islands, including film of the unique fauna found there:
the finches (Darwin’s finches), the giant tortoises and the iguanas in particular. Use these
animals to discuss isolation and speciation.
Involve students in a discussion of the unique fauna of the Australian continent, which is
another excellent example of isolation and speciation. Make sure the discussion includes the
predominance of marsupials and the ecological niches they occupy, and compare these with
the placental mammals of Asia or Africa.
Hold a class debate in which teams of students put forward scientific evidence for and against
the theory of evolution by natural selection. Ensure evidence is presented from scientific
observations in: geographical distribution of organisms, comparative anatomy, molecular
biology, embryology, taxonomy and palaeontology. Students could select or be allocated a
specific piece of evidence to research to bring to the debate.
251 | Qatar science scheme of work | Grade 11 advanced | Unit 11AB.6 | Biology 6
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Objectives
Possible teaching activities
Notes
School resources
Get students to compare the Darwin–Wallace theory of natural selection with the theory of
Lamarck, who proposed that evolutionary change could be achieved by the transmission of
acquired characteristics. This could be part of the debate on evolution. Emphasise the mass of
evidence in support of the Darwin–Wallace theory and the lack of support for Lamarck’s ideas.
The overwhelming direct evidence of natural selection comes from the fossil records, which
provide a trace of evolutionary pathways over millions of years.
Show students examples of fossils and/or visit a museum to see exhibits of fossils.
1 hour
Adaptation to environment
Give examples and
explanations of how
organisms are adapted to
survive in particular
environmental conditions.
Provide specimens of fossils.
Visit opportunity: Visit a natural history museum.
Select some examples of animals from a variety of environments and ask students to write a list
of the ways the animal is adapted to its particular environment (e.g. polar bears or seals in the
Arctic, whales or sharks in the oceans, swifts or swallows in the air of many continents, zebras
or lions in the tropical savannah).
Similarly, select some plants from a variety of environments and carry out the same exercise
(e.g. aquatic plants such as water lilies, marginal plants such as reeds, marram grass
(Ammophilia arenaria) of sand dunes, succulents and cacti of deserts).
Present students with pictures of specific organisms and ask them to match these to
descriptions of their adaptations for living in their natural habitat.
252 | Qatar science scheme of work | Grade 11 advanced | Unit 11AB.6 | Biology 6
Provide a set of pictures of a variety of specific
organisms and a separate set of descriptions of
their adaptations.
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Assessment
Examples of assessment tasks and questions
Assessment
Set up activities that allow
students to demonstrate what
they have learned in this unit.
The activities can be provided
informally or formally during
and at the end of the unit, or
for homework. They can be
selected from the teaching
activities or can be new
experiences. Choose tasks
and questions from the
examples to incorporate in
the activities.
Unit 11AB.6
Notes
School resources
How does the innate territorial behaviour of a bird help to ensure the survival of the species?
Suggest a possible way the unique fauna of Australia may have arisen.
Give alternative explanations that might have been given by Lamarck and Darwin to explain the
giraffe’s long neck.
Explain the adaptations shown by the crocodile that have enabled this animal to survive as a
species for many millions of years.
253 | Qatar science scheme of work | Grade 11 advanced | Unit 11AB.6 | Biology 6
© Education Institute 2005
254 | Qatar science scheme of work | Grade 11 advanced | Unit 11AB.6 | Biology 6
© Education Institute 2005