Introduction

1. Introduction Introduction Modular 4

2. Lucy’s Brain: Earliest Ancestor • Lucy was 4 feet tall and weighed 55 pounds • Anthropologist think Lucy did not make tools, knew nothing of fire, and conversed with hand gestures, waves, and grunts • Lucy’s species, was named the Australopithecus afarensis and lived 3 million years ago and may be the earliest ancestor of modern humans

3. Baby Theresa’s Brain: Fatal Flaw • Baby Theresa was born with almost no brain • She survived for 9 days because very primitive part of her brain was still functioning • The area is located directly above the spinal cord and regulates vital reflexes, such as breathing, blood pressure, and heart rate

4. Steve’s Brain: Cruel Fate • Steve was a successful journalist and one day he was unable to tell time by sight but could by sound

5. Scott’s Brain: Wrong Instructions • Scott as an infant could not stop crying • As he got older he couldn’t sit up, refused to play with other children, and often he was off in a world of his own • Scott’s genetic makeup showed that he had fragile X syndrome

6. What’s coming • Lucy’s brain brings up the question of evolution • Theresa’s brain raises the question of what it means to be human • Steve’s brain brings up the question of what to do when brains are damaged • Scott’s brain brings up the question of why things go wrong

7. Genes & Evolution Section A Modular 4

8. Genetic Instructions • Your brain and body develop according to complex chemical instructions that were written in a human cell no larger then a grain of sand • Fertilization • The sperm contain 23 chromosomes and the Egg contain 23 chromosomes • When fertilized this becomes a Zygote

9. Genetic Instructions • Zygote • The cell that results when an egg is fertilized– equivalent of 300,000 pages of typewritten instructions • Chromosomes • Inside the zygote are 23 pairs of chromosomes which contain chemical instructions for development of brain and body • Hair like strand that contains tightly coiled strands of the chemical DNA

10. Genetic Instructions • Chemical alphabet • Long strands of DNA • Resembles a ladder that has been twisted • Each rung of the DNA ladder is made up of four chemicals • The chemical alphabet is used to write instructions for the development and assembly of billions of parts that make up the brain and body • Genes and proteins • A gene is a specific segment on the long strand of DNA that contains instructions for making proteins • Proteins are chemical building blocks from which all the parts of the brain and body are constructed

11. Genetic Instructions • Genome • This is the project to identify all human genes • There are about 30,000 human genes • Hopefully this research can be used to find answers to genetic problems and solutions to some other diseases • Scott’s brain: An error in instructions • Fragile X syndrome is caused by a defect in the X chromosome • This results in a relatively large head with protruding ears, as well as mild to profound levels of mental retardation • It shows what happens when there is an error in genetic instruction

12. Evolution of the Human Brain • What is evolution? • Charles Darwin published Origin of Species in 1859 • In the book he put together his basis for evolution • Theory of evolution says that different species arose from a common ancestor and that those species that survived were best adapted to meet the demands of the environment • This is a theory and has been backed up by scientific evidence but clashes with religious doctrine • According to the theory humans split off from the apes millions of years ago (human DNA shares at least 98.5% of chimpanzee DNA)

13. Evolution of the Human Brain Perhaps the First Human Brain • The earliest ancestors of humans (brains) lived about 3 to 4 Million years ago • The ancestor is given a common name (Lucy) and the scientific name is Australopithecus afarensis

14. Evolution of the Human Brain Perhaps the First Human Brain • Lucy’s brain is about one third the size of our brain today • She had long powerful arms and short legs and lived on leaves and fruit • Her kind used no tools and had no fire • Lucy’s kind died out about a million years ago

15. Evolution of the Human Brain Brain Doubles in Size Homo erectus had a skull twice the size of Lucy’s Homo erectus lived about one and half million years ago Erectus walked upright and was as tall as modern humans It is thought that they added meat to their diet Erectus had a larger brain and used tools The best tool was a hand ax Decedents of erectus developed even larger brains (Homo sapiens)

16. Evolution of the Human Brain Brain Triples in Size • The largest brain comes form modern humans known as homo sapiens • The species began about 400,000 years ago • The brain is about 3 pounds

17. Evolution of the Human Brain Brain Triples in Size • There were four dramatic changes with this brain size– growing crops, live in social communities, developed language, and painted depictions • Two changes lead to the larger brains– genetic mutation and natural selection– sapiens were better suited for their environment • This took millions of years to occur