Earth

How did life begin on Earth ?

The Bible teaches that God created all life on earth. But evolution teaches that life started by a purely natural process. What does the scientific evidence tell us ?

Achievements of Science

• Physics– Law of Gravity (Newton)– Law of Electromagnetism (Maxwell)– Structure of the atom (Bohr, and others)

• Chemistry– Periodic table – chemical properties– Organic chemistry

• Molecular-biology– DNA structure– Cell chemistry

• How does science discover these truths ???

How science discovers the truth

• Science tries to find explanations for things we can observe

• Scientific method:1. Observe and gather information2. Propose a theory (a “good” guess)3. Devise experiments to test the theory4. See if results of experiments check

out with the theory5. If not, change theory and try again6. If so, theory becomes a “law”

Example:

So is Evolution a proven theory ???• A recent PBS TV series on Evolution

claims that:– All known scientific evidence support

evolution – Virtually every reputable scientist in the

world support evolution • School text books on evolution all

proclaim that “Evolution is a proven fact”• Many people who once believed that God

created the world turned away from God after they learned about the Theory of Evolution... (anyone here ?)

What are living things made of ?

0.01 mm

Cell

Structure of a living cell• We now know the cell is extremely complex:

• In Darwin days, they thought the cell was simply a blob, like “dough” (bad microscopes)

What is a cell made of ?

Cell

Millions ofproteinmolecules

Amino-acid molecule

Chain of 100’s of amino-acid molecules

• 20 different amino-acid molecules in cells:

• Each protein molecule is made of different combinations of amino-acids:

• Q: How many different protein molecules ?

Amino-acids: building blocks of life

Example protein molecule:

Another example:

Protein molecules used in cells

• There can be infinitely many different protein molecules– Analogy: – 10 digits (0, 1, 2, 3, 4, 5, 6, 7, 8, 9)– Each number is made of different

combination of 10 digits (123, 27632, 67, …)

– We can make up infinite many different numbers

• Living cells use over thousands of different kinds of protein molecules

What do you need to do to make life ?1 Cell

Millions ofproteinmolecules

Lots and lots and lots of different kinds of amino-acid molecules

Lots and lots of diff kinds of protein molecules

What do you need to do to make life ?• Make billions of amino-acid

molecules (of different kinds)

Amino-acid molecules come in 2 flavors: left handedand right-handed. Life only use left-handed molecules

What do you need to do to make life ?• Pick the right kinds of amino-acid

molecules in the right order to make millions of protein molecules

Some protein molecules have over 1000 amino-acids !

Pick only left-handed ones !Put in the right order !

What do you need to do to make life ?• Pick the right kinds of protein

molecules and put them together in the right way to build ONE SINGLE cell

Tens of thousands different kinds of proteins

Millions ofprotein molecules

Cell: your worst 3D Chinese Jigsaw puzzle nightmare...

So can we make a living cell ?

• With all our current advanced knowledge and technologies, we cannot make a living cell from scratch...

• Suppose we would break apart a living cell, we could not put the cell back together again...

Now we can talk about Evolution

• What I describe next is the “theory” or “guess” that science has proposed to explain how life began on earth

• I will describe the theory in its entirety first

• As for all science, a theory (guess) must be supported by evidence – I will present the scientific evidence after presenting the Theory of Evolution (and explain what’s wrong with the theory)

Evolution: How did life begin (1)

• Early earth’s atmosphere contains Hydrogen, Methane, Ammonia, Nitrogen gases

• Lightning provided energy to fuse the gases into different Amino-acid molecules

• Amino-acid molecules collide with one another to for protein molecules

• Protein molecules collide with one another to form a living cell

Evolution: How did life begin (2)

• At first, life was very simple and consist of “self replicating molecules”

• Later, life learn to store genetic information in DNA molecules: single cell organisms (bacteria)

• And later, single cell organisms developed into simple multi-cell orgasms (Example: coral polyp)

Evolution: How did life diversify ?

Life “changes”slowly overlong time…

Bil

lion

s of

yea

rs

Evolution: how did life diversify ?

• When more and more living organisms are on earth, they compete for their food

• The stronger (faster, smarter, etc) animals will have a better chance to survive and reproduce

• This process of adaptation is called “natural selection”

Science: always check the evidence

• A scientific theory is only a guess – it can be wrong !

• The principle in science is to always check the theory against the evidence

• The evidence is never wrong

• So do we have strong evidence for the Theory of Evolution ?

“Making amino-acid” according to Evolution

• Put Hydrogen, Methane, Ammonia, Nitrogen together

• Use lightning (electric sparks) to fuse the gases into different Amino-acid molecules

• Any evidence that this can be done ?

Making Amino-acids: Miller’s experiment

• Miller put water, nitrogen, methane, ammonia, hydrogen and carbon dioxide in a flask

• The mixture was zapped for a week by high voltage sparks

• Miller was able to make a number of different types of amino-acid molecules

• Some scientists saw this as “proof” that life began on earth through evolution

Evolution: life have common ancestor

• All life started from a common ancestor

• Is there any evidence for this fact ???

Evidence 1 for common descend: embryos• Haeckle showed

embryos at different stages of their development (1874)

• Haeckle’s drawing shows that embryos from different species look alike at the start of their development

• Many biology text books claim that this shows that all living things had a common ancestor

Evidence 2 for common descend: structure

• The skeleton of vertebrates have a common design: looks like coming from one common ancestor

Fossil record in reality• Bacteria (procaryotic cells) 3,500 millions years ago • Complex (eucaryotic cells) 2,000 millions years ago• Multicellular animals (jelly fish) 670 millions years ago• Shell-bearing animals (insects) 540 millions years ago• Vertebrates (simple fishes) 490 millions years ago• Amphibians (frogs) 350 millions years ago• Reptiles (lizards) 310 millions years ago• Mammals 200 millions years ago• Nonhuman primates 60 millions years ago• Earliest apes 25 millions years ago• Modern humans 0.15 millions years ago

Over 100,000 species of insects appeared suddenly