Loading in 2 Seconds...
Loading in 2 Seconds...
National 4 Biology Key Area 5: Adaptations for survival. National 5 Biology Key Area 4: Adaptation, natural selection and the evolution of species. Cystic Fibrosis. What caused all of these?. Haemochromatosis.
Key Area 5:
Adaptations for survival
National 5 Biology
Key Area 4:
Adaptation, natural selection and the evolution of species
Agenetic disorder causing the body to absorb an excessive amount of iron from the diet: the iron is then stored in various organs.
Cystic fibrosis is a genetic condition in which the lungs and digestive system become clogged with thick sticky mucus
Tay-Sachs disease is a rare and usually fatal genetic disorder that causes progressive damage to the nervous system.
Symptoms usually appear at around 6 moths old and most affected children will die by the age of 3.
Huntington's disease is an inherited disease of the brain that damages certain brain cells.
This can affect movement, cognition (perception, awareness, thinking, judgement) and behaviour
All of these conditions were caused by a spontaneous and random change or mutation in a persons’ DNA
This mutation was inherited from their parents.
Malignant Melanoma (Skin cancer)
Not all mutations are inherited. Exposure to certain factors, UV light in sunlight can cause spontaneous mutations that lead to cancer.
We now know that exposure to most radiation (UV, gamma and even X-rays) can be carcinogenic.
Exposure to some chemicals can also lead to a spontaneous mutation in our DNA that can lead to cancer.
A mutation is a spontaneous change to genetic material.
A mutagenic agent is a factor such as radiation (gamma or X-rays), UV light or some chemicals (e.g. those in cigarette smoke) that can increase the rate of mutations.
They had a mutation that made them resistance to the plague bacterium
Advantageous: e.g. bacterial resistance to
Neutral: e.g. Free Ear lobes or attached ear lobes.
Disadvantageous: Malignant Melanoma
(Up to 21 minutes)
Theologist and self-taught naturalist.
Believed living things evolved.
Suggested evolution happed by natural selection or “survival of the fittest”.
Gathered detailed evidence from voyages (e.g. The Galapagos Islands) to support his theory.
Darwin did not provide an explanation of how features were passed on.
Inspired by the nature of the island chain
When and where he started thinking about what was to become his theory of evolution by natural selection.
Animals live there that are found nowhere else on earth.
This makes them endemic
1. Species were not created in their present form, but evolved from ancestral species.
2. Proposed a mechanism for evolution:NATURAL SELECTION
What does this mean?
Can you think of any examples?