Evolution
BIOLOGY PRESENTATIONDONE BY: LAILA BANGWAR &
LUJANE PAGGANWALA
What is Evolution
“Defined as a process of Cumulative change in the Heritable characteristics of a population.”
Evidence for evolution by Fossil records
• There are several ways of proving evolution through the process of natural selection.
• Fossil records are one of the ways.
Artificial Selection
• Another way to prove evolution is by artificial selection.
• What is artificial selection?
Homologous anatomical structures
• Homologous anatomical structures is another way that evolution is proven
• What is Homologous anatomical structures?
Over-production of offspring
• Many times populations over produce offspring, more then what the environment can handle or support.
• Some organisms which do so are:-Plants-Mushrooms-Fish
Why the environment cannot support the over production of off springs
• The environment cannot support all the offspring due to lack of availability of water and other nutrients in order for the offspring to survive.
Consequences of over-production
• The result of overproduction causes a competition between the organisms in order to survive. Also known as the struggle of survival.
• It could be explained as survival of the fittest, as Charles Darwin himself referred it, though it is much more complicated then just that.
Variation
• Some members of a species show variation.• Usually those who sexually reproduce, show
more variation
Natural selection
• Charles Darwin’s most famous theory.• What is natural selection?• Steps involved in evolution by natural selection:-overproduction of offspring-Variation in offspring, both harmful and beneficial-environmentally adapted genetic characteristics-Passing on of favorable genetic characteristics-All this accumulates to result in evolution.
Examples of evolution-in response to environmental change
• Evolution usually is a time consuming process, but sometimes natural selection may take place quicker, in months or decades, instead of a million years.
• Two examples of natural selection could be:- Antibiotic resistance in bacteria- Pesticide resistance in rats
Antibiotic resistance in bacteria
• Antibiotics are basically medications which kill bacteria.
• In certain conditions, some bacteria may become resistant to the antibiotic.
• This takes place due to two reasons which are:-Mutations-Plasmid transfer
Pesticide resistance in rats
• Pesticides are those chemicals which are used to kill organisms that are pests such as rats.
• Just like how bacteria become resistant to some antibiotics, pests (in this case, rats) become resistant to pesticides, in some conditions.
Evolution
Bibliography
• Charles Darwin & Evolution. (n.d.). Charles Darwin & Evolution. Retrieved August 14, 2014, from http://darwin200.christs.cam.ac.uk/pages/index.php?page_id=d3
• Introduction to Evolution. (n.d.). Vimeo. Retrieved August 17, 2014, from http://vimeo.com/19451460
• Ward, W., & Damon, A. (2007). Pearson baccalaureate: higher level (plus standard level options) : biology developed specifically for the ib diploma. Harlow, [England: Pearson Education.
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