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.

THE END.