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Humman Races

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by

sameh gohar

on 7 December 2013

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Transcript of Humman Races

Human Races
What is the human race?
A group of people with certain common inherited features that distinguish them from other groups of people.


Types of human races
1. Caucasians
2. Negroids
3. Mongoloids
4. Australoids
Diseases related to each race

1. Caucasians : Skin cancer
2. Australoids : Heart disease malaria
3. Mongloids : Down’s Syndrome
4. Negroids : Vitamin D deficiency

How did races developed?
Caucasians
Site: Europe, Western Asia, Northern Africa
Skull: Long-headed, High forehead
Face: Narrow, Meso- or Euryproscopic
Nose: long, narrow, high
Lips: medium
Skin: Pure white to rich brown
Hair: Blonde to black
Australoids
Site: Indonesia, Melanesia, Malaysia
Skull: Long-headed
Face: Large & heavy jaws, wide nose, and thick lips
Skin: Brown to black
Hair: Silky, black, wavy
Negroid
Site: Africa from Senegal along the coast of South Guinea
Skull: Forehead most often high
Face: High cheek bones, broad nose, broad and small chin, white teeth
Skin: Black
Hair: Curly & dark
Mongoloids
Charles Darwin (1807-1882)
is an English naturalist and geologist who established many evolutionary theories
One of them is NATURAL SELECTION.
According to the theory, nature "selects" the individuals with the most suitable characteristics to survive.
Meaning that, the individuals that will best adapt to the surrounding environmental changes are the ones that will be able to survive.
Adaptation of human races
Skin and hair :



The two main theories of Evolution
OUT OF AFRICA THEORY (OOA) :
-Suggests that Homo erectus evolved into Homo sapiens in Africa, and then ventured out of Africa and dispersed to all around the world.
MULTI-REGIONAL EVOLUTION THEORY :
- Suggests that Homo erectus ventured out of Africa and then evolved into modern man in several different locations through out the world.

Skin and hair colors are primarily due to a pigment called "melanin", which absorbs UV rays. People with dark skin have a great amount of melanin.The darker of the skin the greater of melanin and vice versa.
Nature has selected people with darker skin where the ultraviolet radiation from the sun is the most intense. Melanin helps to prevent sunburn damage that could result in DNA changes and subsequently several kinds of maligant skin cancer (MELANOMA).

It also prevent Vitamin D toxicity
On the other hand, nature selects people with less melanin where ultraviolet radiation is weak. In such an environment, very dark skin is a disadvantage because it can prevent people from producing enough Vitamin D, which potentially results in rickets disease in children and osteoporosis in adults.
1-what is race
2-Types of human races
3- Race-related diseases
4- Development of races
5- Adaptation of human races


Objectives to know:
Natural Selection & Human Races
In the early centuries, humans started to migrate and encounter different environments. But only individuals with characteristics suitable for the new environment were able to live, reproduce, and pass on these traits to their offspring.
PBL 21
Dr. Hussein Abdel Aziz

Site: East Indies, China, Japan, Korea
Skull: Short, round head. Forehead lower than Caucasoids'
Face: Wide & short. Shovel-shaped inscisors
Nose: Low & broad
Eyes: Narrow, almond shaped
Skin: Yellowish
Hair: Light brown
QUESTIONS
Question 1
What is the function of Melanin?

a) To give skin color
b) To absorb UV radiation
c) To permit skin elasticity
d) All of the above
Question 2
What is the reason lighter skin was selected or places where the sun is scarce?

a) Allow synthesis of Vitamin D
b) Dark skin was no longer needed
c) Light skin protects from the sun
d) A & B
Question 3
Nature selects individuals with:

a) Suitable characteristics
b) Largest size
c) Darkest skin
d) Strongest body
Question 4
The skin of a Caucasian can be :

a) Black
b) Yellowish
c) White
Thank You for Watching

Terimah Kasih !
PBL 21
Tutor: Dr. Hussein Abdulaziz

Members:
Muhammad Izzuddin bin Mohd Jalaludin
Muhammad Haikal bin Yusof
Fatin Amirah binti Abdul Rauf
Mariam Mohiy El-Din
Sameh Gohar
Dayang Amirah Damia binti Hamdan
Muhammad Kamal Azam bin Nor Azlan
Muhaimin Azfar bin Rozmi
Muhammad Kumayl bin Mohd Reza
Ehab El-Shobaky
Full transcript