Genetics
Study Guide for Genetics & Evolution
DNA, Genes and Chromosomes
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Know that chromosomes are found in the cell nucleus and that genes are carried on chromosomes
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Living organisms are made of cells → Cells have a nucleus → Nucleus contains Chromosomes → Chromosomes made of DNA → Sections of DNA are genes (chromosomes contain 1000’s of genes)
Genes code for particular characteristics (e.g. hair colour). Base pairs making amino acids that make specific proteins. Each protein is like a lego block. The same shape can be made up of lots of different coloured or different-sized blocks. This creates variation.
DNA is copied when cells divide for growth and repair
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Scale of the Universe interactive | Cell size and scale interactive
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Know that genes are coded instructions for making proteins which show as characteristics.
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BBC Bitesize - Species and Variation
Stated Clearly - What is a gene?
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DNA is the chemical which stores the coded instructions
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Stated Clearly - What is DNA?
Crash Course - DNA Structure
Fuseschool - Genetics & Cell Division
Extension: Various DNA animations
Formation of Gametes
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Know that gametes contain half the normal number of chromosomes and that fertilisation restores the normal number
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humans have 23 pairs of chromosomes (46 in total) and that ½ of those chromosomes are passed on during sexual reproduction, so that the offspring has 23 chromosomes from each parent - totalling 46 chromosomes.
sex cells are called gametes and these gametes contain ½ the number of chromosoms to a somatic cell. They do not need to know the processes of mitosis or meiosis - just need to have an understanding that sex cells contain 23 chomosomes.
fertilisation: sex cells combine to produce a cell that now has 23 pairs of chromosomes = 46 chromosomes.
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Fuseschool - Sex Determination
Inheritance
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Understand the meaning of the terms dominant, recessive, allele and mutation
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Following on from genes - each parent passes on a gene for a particular characteristic (no need to go into several genes controlling a characteristic).
Key words: dominant, recessive, allele and mutation.
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Fuseschool - Punnett Squares
Inheritance - Youtube tutorial
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Calculate and predict the results of a simple cross involving 1:1 or 3:1 ratios using punnett squares
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Fuseschool - Genetic Crosses
Punnett Squares - Youtube explanation
Eye colour - interactive
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Know that the process of evolution is due to variation
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Crash Course - Heredity
Pigeonetics - interactive breeding game
Breeding Angel fish - interactive breeding game
Deer mice - interactive breeding game
Variation
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Appreciate the variation between individuals of a species
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There is variation within our class (e.g. height, shoe size, eye colour- single gene traits).
Some of their characteristics are same/similar to my parents and siblings. Some variations are due to genes that have been passed on from parents to offspring.
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Fuseschool - Variation
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Understand that variation is due to genes being passed on from parents to offspring
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Natural Selection
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Know that organisms vary and that some variations give advantages over others in the struggle for existence
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Variation comes through sexual reproduction but also from mutations
A population will have environmental pressures. Environmental pressures will cause some variations to have an advantage
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The Fittest - Interactive game
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Understand the term natural selection
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Describe how mutations occur (copying, radiation, chemical)
Some of the population will have variations (reproduction or environmental mutations) so will be more likely to survive and reproduce and pass on these variations to their offspring.
Over time these changes in variations of the population can accumulate and become an adaptation.
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Natural Selection by Stated Clearly
Natural Selection - a PHET interactive simulation with bunnies
Fuseschool - Natural Selection
Evolution
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Know that Evolution is the process of change in all forms of life over generations.
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Fuseschool - Evolution
Extension: Speciation - a mutation can be passed on (mutations in reproductive cells are passed on whilst mutations in other cells are not passed on). Fuseschool - New Species
E-coli long term evolution experiment-Wikipedia page
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Know that adaptations are features that organisms/species have to best survive and reproduce in their niche
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Evolution is a gradual change in the inherited traits of a population over many generations. Natural selection is a mechanism where the members of a population best suited to their environment have the best chance of surviving to pass on their genes.
The natural selection of organisms with certain features that enable them to survive in particular environmental conditions has been going since the first form of life appeared on Earth about 3.5 billion years ago. The consequence of this is that species are related and have common ancestors.
NZ example/case study: that many NZ plants/animals are unique due to them evolving in geographical isolation (eg kowhai/tui, kauri, kiwi, kakapo, tuatara)
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Fuseschool - Adaptation
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Know that unrelated organisms may have similar adaptations if they occupy similar niche.
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Understand that organisms that are alive today have changed over time
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Here is today - interactive web site
Geological time - interactive web site
General Resources
Scipad Chapter on Genetics (.pdf)
Stated Clearly - Genetics and Evolution Youtube playlist (8 videos)
Inquiry Science Genetics Youtube playlist
Genetics resources on Sciencelearn.org.nz
National Geographic-Genographic project
Genetics interactives: A page with heaps of different interactives on genetics.
DNA from the beginning: A comprehensive introduction.
Videos:
Hyundai Country Calendar – Series 2017, Episode 2
Hyundai Country Calendar – Series 2017, Episode 25 (9:58 for Semen collecting)
Sex selection: Video on Australian couple who wanted to select sex of baby (13 minutes)
Documentary on Evolution by David Attenborough
Extension Topics
Scale model of DNA: A single human DNA molecule, stretched out a straight line, has a width of about 20 Angstrom (about 2 nanometers or 0.0000002 cm) and a length of approximately 5 cm (source-Wiki answers). How long would our class model need to be to be an accurate length? (Model width is 5.3cm). How many students would be need to make an accurate length of model?
Genetics Webquest: from SciLearn NZ
Seeds of Unease: NZ Geographic article about genetic modification.