Download Topic 5: Evolution

Topic 5: Evolution
Campbell Chapters 22,23,24,25,26,29,30,33,34
*It is strongly recommended that you read and take column notes on all of chapters 22,23 and 26 in addition to answering the
“Understandings” and “Sample Questions and Assessment Statements” below. For all other chapters, simply reading the suggested
pages and doing any more work that you deem necessary will be enough.
Evidence for Evolution: Chapter 22
Essential Idea: There is overwhelming evidence for the evolution of life on Earth.
Nature of Science:
•
Looking for patterns, trends and discrepancies—there are common features in the bone structure
of vertebrate limbs despite their varied use.
Understandings:
1. Evolution occurs when heritable characteristics of a species change. 459
2. The fossil record provides evidence for evolution. 461-462
3. Selective breeding of domesticated animals shows that artificial selection can cause evolution.
458-459
4. Evolution of homologous structures by adaptive radiation explains similarities in structure when
there are differences in function. 463
5. Populations of a species can gradually diverge into separate species by evolution. 498-504
6. Continuous variation across the geographical range of related populations matches the concept of
gradual divergence. Online
Applications and Skills:
•
Application: Development of melanistic insects in polluted areas. Online
•
Application: Comparison of the pentadactyl limb of mammals, birds, amphibians and reptiles
with different methods of locomotion. Online
Sample Questions and Assessment Statements:
•
Define evolution. 452
•
Outline the evidence for evolution provided by the fossil record (461-462), selective breeding of
domesticated animals (458-459) and homologous structures (463-464).
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Describe one example of transient polymorphism. Peppered moth; Online
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State that the members of a species show variation. 468-471
•
Explain two examples of evolution in response to environmental change; one must be antibiotic
resistance in bacteria. 563-564; 572; Online
•
Describe sickle-cell anemia as an example of balanced polymorphism. 483-484; Online
TOK:
•
Evolutionary history is an especially challenging area of science because experiments cannot be
performed to establish past events or their causes. There are nonetheless scientific methods of
establishing beyond reasonable doubt what happened in some cases. How do these methods
compare to those used by historians to reconstruct the past?
Natural Selection: Chapter 22 & 23
Essential Idea: The diversity of life has evolved and continues to evolve by natural selection.
Nature of Science:
•
Use theories to explain natural phenomena—the theory of evolution by natural selection can
explain the development of antibiotic resistance in bacteria.
Understandings:
1. Natural selection can only occur if there is variation among members of the same species. 455459; 475; 479-484
2. Mutation, meiosis and sexual reproduction cause variation between individuals in a species. 258260; 468-471; 481-483;
3. Adaptations are characteristics that make an individual suited to its environment and way of life.
456-459; 481; 484
4. Species tend to produce more offspring than the environment can support. 458-459
5. Individuals that are better adapted tend to survive and produce more offspring while the less well
adapted tend to die and produce fewer offspring. 484; entire unit
6. Individuals that reproduce pass on characteristics to their offspring. 249; 258-260; 468-471
7. Natural selection increases the frequency of characteristics that make individuals better adapted
and decreases the frequency of other characteristics leading to changes within the species. 455459; 475; 479-484
Application and Skills:
•
•
Application: Changes in beaks of finches on Daphne Major.
Application: Evolution of antibiotic resistance in bacteria.
Sample Questions and Assessment Statements:
•
State that populations tend to produce more offspring than the environment can support. 458459
•
Explain that the consequence of the potential overproduction of offspring is a struggle for survival.
458-459
•
Explain how sexual reproduction promotes variation in a species. 249; 258-260; 468-471
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Explain how natural selection leads to evolution. 458-459; 475; 479-484
Guidance:
•
Students should be clear that characteristics acquired during the lifetime of an individual are not
heritable. The term Lamarckism is not required.
TOK:
•
Natural Selection is a theory. How much evidence is required to support a theory and what sort of
counter evidence is required to refute it?
Gene Pools and Speciation Chapter 23 & 24
Essential Idea: Gene pools change over time.
Nature of Science: Looking for patterns, trends and discrepancies—patterns of chromosome number in
some genera can be explained by speciation due to polyploidy.
Understandings:
1. A gene pool consists of all the genes and their different alleles, present in an interbreeding
population. 472-475
2.
3.
4.
5.
Evolution requires that allele frequencies change with time in populations. 472-475
Reproductive isolation of populations can be temporal, behavioral, or geographic. 488-495
Speciation due to divergence of isolated populations can be gradual. 492-498
Speciation can occur abruptly. 495-496; 502-503
Applications and Skills:
Application: Identifying examples of directional, stabilizing and disruptive selection. 479-481
Application: Speciation in the genus Allium by polyploidy. Online
Skill: Comparison of allele frequencies of geographically isolated populations. 472-479
Sample Questions and Assessment Statements:
•
Define allele frequency and gene pool. 472-475
•
State that evolution involves a change in allele frequency in a population’s gene pool over a
number of generations. 472-475
•
Discuss the definition of the term species. 487-488
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Describe three examples of barriers between gene pools. 488-491
•
Explain how polyploidy can contribute to speciation. 495-498
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Compare allopatric and sympatric speciation. 492-498
•
Outline the process of adaptive radiation. 523-525
•
Compare convergent and divergent evolution. 464-465
•
Discuss ideas on the pace of evolution, including gradualism and punctuated equilibrium. 452456; 501-503
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Explain how the Hardy–Weinberg equation is derived. 472-475
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Calculate allele, genotype and phenotype frequencies for two alleles of a gene, using the Hardy–
Weinberg equation. 472-475
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State the assumptions made when the Hardy–Weinberg equation is used. 474
Guidance:
•
Punctuated equilibrium implies long periods without appreciable change and short periods of
rapid evolution.
TOK:
•
Punctuated equilibrium was long considered an alternative theory of evolution and challenge to
the long established paradigm of Darwinian gradualism. How do paradigm shifts proceed in science and
what factors are involved in their success?
Utilization:
•
Many crop species have been created to be polyploidy. Polyploidy increases allelic diversity and
permits novel phenotypes to be generated. It also leads to hybrid vigor.
The Origin of Cells: Chapters 25,26,27 and 28
Essential Idea: There is an unbroken chain of life from the first cells on Earth to all cells in organisms
alive today.
Nature of Science:
•
Testing the general principles that underlie the natural world—the principle that cells only come
from pre-existing cells needs to be verified.
Understandings:
1. Cells can only be formed by division of pre-existing cells. Online.
2. The first cells must have arisen from non-living material. Online; 507-510
3. The origin of eukaryotic cells can be explained by the endosymbiotic theory. 516-517; 576-577
Applications and Skills:
•
Application: Evidence from Pasteur’s experiments that spontaneous generation of cells and
organisms does not now occur on Earth. Online
Sample Questions and Assessment Statements
•
Describe four processes needed for the spontaneous origin of life on Earth. 507-510
•
Outline the experiments of Miller and Urey into the origin of organic compounds. 508-509
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State that comets may have delivered organic compounds to Earth. 508-509
•
Discuss possible locations where conditions would have allowed the synthesis of organic
compounds. 508-509
•
Outline two properties of RNA that would have allowed it to play a role in the origin of life. 509510
•
State that living cells may have been preceded by protobionts, with an internal chemical
environment different from their surroundings. 509
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Outline the contribution of prokaryotes to the creation of an oxygen-rich atmosphere. 516
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Discuss the endosymbiotic theory for the origin of eukaryotes. 516-517; 576-577
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Outline the classification of living organisms into three domains. 551-553
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Explain the reasons for the reclassification of living organisms into three domains. 551-553
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Distinguish between the characteristics of the three domains. 551-553
•
Outline the wide diversity of habitat in the Archae, as exemplified by methanogens, thermophiles
and halophiles. 556-559; 567-570
•
Outline the diversity of Eubacteria, including shape and cell wall structure. Online
•
State, with one example, that some bacteria form aggregates that show characteristics not seen in
individual bacteria. 565
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Compare the structure of the cell walls of Gram-positive and Gram-negative Eubacteria. 557;
Online.
Guidance (Things you need to be able to do):
•
Evidence for the endosymbiotic theory is expected. The origin of eukaryotic cilia and flagella does
not need to be included.
•
Students should be aware that 64 codons in the genetic code have the same meanings in nearly all
organisms, but that there are some minor variations that are likely to have accrued since the
common origin of life on Earth.
TOK:
•
Biology is the study of life, yet life is an emergent property. Under what circumstances is a
systems approach productive in biology and under what circumstances is a reductionist approach
more appropriate? How do scientists decide between competing approaches?
Aims:
•
Aim 6: Pasteur’s experiment can be repeated using modern apparatus.
Classification and Biodiversity: Chapter 26
Essential Idea: Species are named and classified using an internationally agreed system.
Nature of Science:
•
Cooperation and collaboration between groups of scientists—scientists use the binomial system
to identify a species rather than the many different local names.
Understandings:
1. The binomial system of names for species is universal among biologists and has been agreed and
developed at a series of congresses. 536-540
2. When species are discovered they are given scientific names using the binomial system. 536-540
3. Taxonomists classify species using a hierarchy of taxa. 536-540
4. All organisms are classified into three domains. 551-553
5. The principal taxa for classifying eukaryotes are kingdom, phylum, class order, family, genus, and
species. 537-538
6. In a natural classification, the genus and accompanying higher taxa consist of all the species that
have evolved from one common ancestral species. 536-547
7. Taxonomists sometimes reclassify groups of species when new evidence shows that a previous
taxon contains species that have evolved from different ancestral species. 536-547
8. Natural classifications help in identification of species and allow the prediction of characteristics
shared by species within a group.
Applications and Skills:
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Application: Classification of one plant and one animal species from domain to species level.
537-537; handout
•
Application: Recognition features of bryophyta (606-610), filicinophyta (610-615),
coniferophyta (621-625) and angiospermophyta (625-632).
•
Application: Recognition features of porifera (670-671), cnidaria (667; 671-673),
platyhelmintha (674-676), annelida (680-682), mollusca (677-680), arthropoda (684-692) and
chordata (669; 698-702).
•
Application: Recognition of features of birds (718-720), mammals (721-727), amphibians (711713), reptiles (715-718) and fish (706-710).
•
Skill: Construction of dichotomous keys for use in identifying specimens. Lab
Sample Questions and Assessment Statements:
•
Outline the value of classifying organisms. 536-540
•
Explain the biochemical evidence provided by the universality of DNA and protein structures for
the common ancestry of living organisms. 69; 80-89; 442-447
•
Explain how variations in specific molecules can indicate phylogeny. 540-542
•
Discuss how biochemical variations can be used as an evolutionary clock. 549-551
•
Define clade and cladistics. 542-543
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Distinguish, with examples, between analogous and homologous characteristics. 540-541
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Outline the methods used to construct cladograms and the conclusions that can be drawn from
them. 538-548
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Construct a simple cladogram. 538-548
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Analyze cladograms in terms of phylogenetic relationships. 538-548
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Discuss the relationship between cladograms and the classification of living organisms. 538-548
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Outline the binomial system of nomenclature. 536-540
•
•
•
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List seven levels in the hierarchy of taxa—kingdom, phylum, class, order, family, genus and
species—using an example from two different kingdoms for each level. 537-538; Handout
Distinguish between the following phyla of plants, using simple external recognition features:
bryophyta (606-610), filicinophyta (ferns) (610-615), coniferophyta (621-625) and
angiospermophyta (625-632).
Distinguish between the following phyla of animals, using simple external recognition features:
porifera (670-671), cnidaria (667; 671-673), platyhelminthes (674-676), annelida (680-682),
mollusca (677-680) and arthropoda (684-692).
Apply and design a key for a group of up to eight organisms. Lab
Guidance:
•
Archea, eubacteria and eukaryote should be used for the three domains.
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Members of these domains should be referred to as archaeans, bacteria and eukaryotes.
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Students should know which plant phyla have vascular tissue, but other internal details are not
required.
•
Recognition features expected for the selected animal phyla are those that are those that are most
useful in distinguishing the groups from each other and full descriptions of the characteristics of
each phylum are not needed.
•
Viruses are not classified as living organisms.
International Mindedness:
•
There are international codes of nomenclature and agreements as to the principles to be followed
in the classification of living organisms.
TOK:
•
The adoption of a system of binomial nomenclature is largely due to Swedish botanists and
physician Carl von Linne, Carolus Linnaeus (1707-1778). Linnaeus also defined four groups of
humans, and the divisions were based on both physical and social traits. By 21st-century
standards, his descriptions can be regarded as racist. How does the social context of scientific
work affect the methods and findings of research? Is it necessary to consider the social context
when evaluating ethical aspects of knowledge claims?
Cladistics: Chapter 26
Essential Idea: The ancestry of groups of species can be deduced by comparing their base or amino acid
sequences.
Nature of Science:
•
Falsification of theories with one theory being superseded by another—plant families have been
reclassified as a result of evidence from cladistics.
Understandings:
1. A clade is a group of organisms that have evolved from a common ancestor. 542
2. Evidence for which species are part of a clade can be obtained from the base of sequences of a
gene or the corresponding amino acid sequence of a protein. 541-548
3. Sequence differences accumulate gradually so there is a positive correlation between the number
of differences between two species and the time since they diverged from a common ancestor.
549-551
4. Traits can be analogous or homologous. 463-466; 540-541
5. Cladograms are tree diagrams that show the most probable sequence of divergence in clades.
542-548; handout
6. Evidence from cladistics has shown that classifications of some groups based on structure did not
correspond with the evolutionary origins of a group or species. 542-548
Applications and Skills:
•
Application: Cladograms including humans and other primates. 723-733; handout
•
Application: Reclassification of the figwort family using evidence from cladistics. Online
•
Skill: Analysis of cladograms to deduce evolutionary relationships. 542-548; online; handout
Sample Questions and Assessment Statements:
•
Describe the major anatomical features that define humans as primates. 728-733
•
Outline the trends illustrated by the fossils of Ardipithecus ramidus, Australopithecus including
A. afarensis and A. africanus, and Homo including H. habilis, H. erectus, H. neanderthalensis and
H. sapiens. 728-733; Online; Movie
•
State that, at various stages in hominid evolution, several species may have coexisted. 729; Movie
•
Discuss the incompleteness of the fossil record and the resulting uncertainties about human
evolution. 728-733
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Discuss the correlation between the change in diet and increase in brain size during hominid
evolution. Movie
•
Distinguish between genetic and cultural evolution. 450-467; Movie
•
Discuss the relative importance of genetic and cultural evolution in the recent evolution of
humans. Movie
TOK:
•
A major step forward in the study of bacteria was the recognition in 1977 by Carl Woese that
Archaea have a separate line of evolutionary descent from bacteria. Famous scientists, including
Luria and Mayr, objected to his division of the prokaryotes. To what extent is conservatism in
science desirable?