Environment 5: Grade 12

Grade 12: Eco Curriculum


D. People and places: rural and urban settlement (Context: South Africa and Africa)
■ With regard to processes and spatial patterns involved in rural and urban settlements:
• settlement function, size and situation, density, hierarchy, services, (urban) profile;
• population size, structure and patterns, land use characteristics, land use zones, the sphere of influence.
■ Key human-environment interactions in rural settlements:
• settlement issues: rural depopulation, closure of services, ageing of population, political influences, governance of rural settlements (local authorities, Agenda 21).
• post-modern urban settlements
Key sustainability-related strategies include:
• rural: sustainable strategies to manage dwindling rural settlements, land reform and land redistribution,
• urban: new towns, inner city renewal, self-help cities, urban planning, sustainable strategies to manage
expanding centers, informal settlements;


Define genetics

Describe mutations as follows: (link with evolution, later)
• Gene and chromosome as changes in the copying process during DNA
• Differentiate between point and frameshift mutation (including deletion,
insertion and inversion)
Differentiate between addition or deletion of a chromosome and addition of
of a set of chromosomes
• Causes of mutations
Define natural selection and describe the role of mutations in natural selection

Genetic Modification
Explain what is meant by selective breeding  and list advantages of this process
Explain what is meant by genetic modification
Briefly describe each of the following with regard to genetic modification:
• Production of human insulin using bacteria (done earlier under DNA)
• The creation of a animal that looks like the extinct quagga
• The advantages and disadvantages of genetically modified foods
Various viewpoints on cloning

Pedigrees and genetic counselling
Interpret pedigree diagrams to trace the inheritance of characteristics over many generation
Explain how pedigree diagrams can be used in:
• Predicting the characteristics of offspring
• Selective breeding
• Genetic counselling

Define the terms: population and a species
Explain what is meant by diversity and how the discovery of new species increases this biodiversity
Explain what is meant by extinction and that how this leads to a decrease in biodiversity
State that there are differences in the appearance of organisms within a species, listing sources of this variation, namely:
• Meiosis (crossing over and random arrangement of chromosomes)
• Mutations
• Reproduction (random fusion of gametes)
Differentiate between evolution and biological evolution
State that evolution may lead increased diversity or to extinction of species

Early theories of evolution
Jean Baptiste de Lamarck
(1744 – 1829)
Describe the following two “laws” of Lamarck
• Law of use and disuse
• Law of inheritance of modified characteristics
Describe examples of the application of Lamarck’s theory such as in the long neck of giraffe, the legs of snake, etc
Explain why Lamarck’s theory is not accepted by most life scientists today since
• there is no evidence to show that changes brought about by adaptation to environment are inherited from parent to offspring
Lamarck believed in determinism (internal drive of organisms to change)

Charles Darwin
Describe Darwin’s Theory of Evolution by Natural Selection

• The historical development:
o Darwin’s 5-year voyage around the world in the HMS Beagle, collecting specimens and keeping notes of plants, animals seen and geography of countries visited such as tortoises, finches, etc
Publication of Darwin’s On the Origin of the Species  in 1859
Observations on which Darwin based his theory:
o Offspring of the same species produce a large number of offspring
o Variations within species
o Of the large number of offspring produced, only a few survive
o Survival of organisms as a result of natural selectioConduct a practical activity to show the variation that exists within the offspring of a species and that not all offspring survive such as by planting mustard seeds, observing the appearance of the seedlings and recording the proportion of seeds that germinate/seedlings that survive for a certain period of time.
Outline differences between de Lamarck and Darwin’s  theories
Current knowledge

State that current knowledge of evolution supports Darwin’s ideas but in addition….
• provides explanations for Darwin’s observations of variation of offspring e.g. Finches of Galapagos
• makes a distinction between micro-evolution, speciation and macro-evolution
• attempts to provide explanations for mass extinctions
• provides “evidence” for evolution                 .

Variation as an explanation for evolution
State that phenotypic variation is a result of genetic variation e.g. Finches of Galapgos, cheetah or the White lion

Explain the role of each of the following as sources of variation:
• Meiosis (crossing over and random arrangement of chromosomes)
• Mutations (gene and chromosome)at cellular and molecular level (lethal, neutral or fixed mutations)
• Reproduction (random fusion of gametes)

Choose TWO examples (one human and one non-human) to illustrate the practice of inbreeding and outbreeding in population e.g. plants, animals and humans by looking at advantages and disadvantages of each

Using examples, explain how variation over a period of time can lead to:

• micro-evolution (variation within a species)
• speciation (formation of new species at ecological, reproductive and genetic level)
ONE example of allopatric and ONE example of sympatric speciation
macro-evolution (patterns, trends and rate of change among lineages over geological times)

Evidence of evolution
Outline the contribution of each of the following in providing evidence for evolution:
• Paleontology
o State what a fossil is
o State the role of fossils in understanding ancient life
o Explain how fossils are formed
o Explain how interpretation of fossil records help to develop patterns of development amongst species through the observation of homologous and analogous structures
o Radiometric dating as a method of finding out the age of fossils using radioactive chemicals
o List the uses of fossils in what the fossil record tells us about :
• the age of the Earth
• when life forms first developed
• the complexity of  life forms today compared to those that existed in the past
• the appearance of today’s life forms compared to those that existed in the past

• Comparative embryology
o Comparison of the embryos of different vertebrates to show similarities

• Comparative anatomy
o Comparison of homologous and analogous structures among organisms to show similarities and differences eg. homologous bone structures in the front limbs of different vertebrates, vestigial structures
• Comparative biochemistry (Can link with Genetics in Term 1)
o List the following features that show possible common origin of different organisms
• Identical DNA structure
• Similar sequence of genes
• Similar portions of DNA with no function
• Identical protein synthesis
• Similar metabolic pathways such as glycolysis, Kreb’s cycle and electron transport system
• Biogeography
State that different but closely related species in similar biomes across the world have similar features in adapting to that biome, indicating that they probably developed from a common ancestral species

Mass Extinctions
State what is meant by mass extinction

State that mass extinctions are periods in the Earth’s history when the biodiversity crashes

Describe the contribution of the following factors to the five major mass extinctions:

• Earthly Theories of Mass Extinctions (related to factors concerning the earth)

o Ice Ages
o Continental drift
o Plate Tectonics
o Volcanic activity
o Disease

• Extraterrestrial Theories (due to factors outside of the planet Earth)

o “Something large” from outer space struck the Earth. This “something large” may have been comet, a an asteroid or part of a star (Vredefort)
o Results of this something large striking Earth :large clouds of dust blocking out sun and stopping   photosynthesis, global cooling, world-wire fires, monstrous tsunamis, extinction of many forms of life (SA Examples)

Alternatives to the Evolutionary Theory of Diversity
Arguments against evolution
Age of the Earth
The probability of forming organic molecules by chance
The tendency towards disorderliness
Gaps in the fossil record
ENVIRONMENTAL STUDIES (Local Environmental Issues)

Explain of the following concepts studied in Grades 10 and 11in a local environment
• Ecosystem
• Environment
• Biotic and abiotic components
• Interactions between the biotic and abiotic components such as  food chains, food webs and energy flow,
competition and predation

Explain extinction and loss of biodiversity (studied in Grades 10 and 11) as it relates to of local indigenous resources by focussing on:
• Threats to biodiversity
• Categories of organisms which are extinct or threatened with extinction
• Examples of South African organisms which are extinct or threatened with extinction
Review of the Red-data listing