SCIM1040 Lecture Notes - Lecture 7: Coccyx, Pentadactyl, Living Fossil
5 Jun 2018
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SCIM1040- Lecture 7
Darwin used farm animal breeding, i.e., artificial selection, to support his theory. (Remember that
humans select the variations that they want, it is not a natural process of selection.)
All finches, for example, had dull coloured feathers, short tails, and laid four pink and white eggs in
nests with small roofs BUT they all had different beaks.
On one island they had strong thick beaks for cracking open nuts and seeds. On another island eighty
kilometres away they had long thin beaks for catching insects.
What is evolution?
• Evolution = Change OR Descent with modification
Time
• Evolution explains the diversity of life, not how life first appeared on Earth.
• It is a scientific theory that is NOT just a belief, but a solid, well-supported, and tested
explanation of changes in life over time with evidence.
• Evolution is caused by changes in the genetic composition of a population during
successive generations, resulting in the development of new species.
• Evolution does not occur in individuals but in populations of species.
• Changes that happen to an organism in their lifetime do not always get passed on to their
offspring.
It is a process in which a population of organisms changes into a different and usually more
complex or more successful form of life over long periods of time resulting in improved abilities to
survive and reproduce. However, while many changes are beneficial for natural selection,
organisms do not always get better.
What are the six kingdoms of life?
1. Archaebacteria
2. Eubacteria
3. Protista
4. Fungi
5. Plantae
6. Animalia
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In the early 1800s prevailing belief was that organisms were specially created and unchanged since
their creation. In other words, it was thought that species were created independently of each other
and did not change. There is much evidence to the refute this. All currently living organisms on Earth
share common DNA. The different animals we see today are due to lots of small changes that have
happened in living things since the last universal ancestor which lived billions of years ago, e.g.,
probable remains of life were found in 4.1 billion-year-old rocks in Western Australia in 2015.
The classic example that he cited was a giraffe – he said that a giraffes ek got loger as it
stretched for leaves higher up on trees. They passed this change onto their offspring, so they had
necks longer as well. NO!
New or more competitive species better able to adapt to changes, such as climate variations,
depletion of food sources, or the emergence of new types of disease.
evolution in action- peppered moths in industrial England
1700s - most moths were grey.
Trees had grey bark.
Black moths were rare.
Late 1700s = Industrial Revolution and black soot clung to trees.
Grey moths stood out and were eaten by birds.
Black moths were not eaten as much and survived to reproduce.
By 1850 all moths were black.
Today, grey peppered moths have once again become common due to environmental
improvement so allowing them to be breed and become more camouflaged on the tree
trunks.
Climate Change can influence evolution
Antitbiotic and pesticide resistance: modern-day dilemmas
There is evidence of natural selection taking place today, and it is an undeniable fact.
1. Years ago, a revolution occurred in medicine. Antibiotics were discovered to treat infections.
• However, since bacteria can rapidly produce new generations then some bacteria have
now evolved to become resistant to the effect of some antibiotics.
• Currently bacteria are becoming more and more resistant to antibiotics such as penicillin.
So, now doctors are faced with the problem of finding
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Document Summary
Darwin used farm animal breeding, i. e. , artificial selection, to support his theory. (remember that humans select the variations that they want, it is not a natural process of selection. ) All finches, for example, had dull coloured feathers, short tails, and laid four pink and white eggs in nests with small roofs but they all had different beaks. On one island they had strong thick beaks for cracking open nuts and seeds. On another island eighty kilometres away they had long thin beaks for catching insects. Evolution explains the diversity of life, not how life first appeared on earth. It is a scientific theory that is not just a belief, but a solid, well-supported, and tested explanation of changes in life over time with evidence. Evolution is caused by changes in the genetic composition of a population during successive generations, resulting in the development of new species.
