Theories Of The Origen Of Life
Scientific Theories
3. Panspermia
1. Lithopanspermia:
Life traveled inside rocks or meteorites from one planet to another. Example:
Microbes could move from Mars to Earth on a space rock.
2. Radiopanspermia:
Very tiny organisms were pushed by light or radiation through space.
3. Directed
Panspermia: Life was sent on purpose by intelligent beings (like aliens) to
start life on Earth.
1. Begin: to
start something
2. Planet: a
large round object in space that moves around a star
3. Species: a
group of living things that are similar and can have babies together
4. Extinct: when
all animals or plants of one kind have died
5. Crystal: a
solid material with a regular shape, like a piece of shiny rock
6. Origin: the
beginning or where something comes from
7. Exist: to
be real or to be alive
8. Surface: the
outside part of something (like the top of the Earth or water)
9. Element: a
simple chemical substance such as oxygen or carbon
10. Compound: a substance made from two or more
elements
11. Universe: everything that exists, including
all stars, planets, and space
12. Microorganism: a very small living thing that you can only see
with a microscope
13. Asteroid: a small rocky object that moves
around the sun
14. Radiation: energy that travels through space,
for example from the sun
15. Hypothesis: an idea or explanation that scientists
test to see if it is true
16. Civilization: a group of people with an organized
society and culture
17. Evolve: to change slowly into a more advanced form
18. Extreme: very great, strong, or serious
19. Survive: to continue to live in difficult conditions
20. Mystery: something that is not known or
understood
Answer the questions:
1. How old was the crystal found in Western Australia, and
why is it important?
2. Which elements are mentioned that life functions through?
3. What is the meaning of panspermia, as explained in the
video?
4. What is radiopanspermia?
5. What is intentional panspermia (or directed panspermia)?
6. How old is the Earth according to the video?
7. What happened after the Earth cooled down?
8. What are extremophiles?
9. Where were extremophiles discovered in the 1970s?
10. What question does panspermia still not answer?
2. Hydrothermal Theory
Principal Ideas:
* Hydrothermal vents may have had the right conditions for the
first life on Earth.
*Archaea, very old and simple organisms, live in hydrothermal
vents.
*Some scientists think complex cells (eukaryotes) came from
simple cells in these vents.
Hydrothermal vents are holes in the bottom of the ocean. They are very hot and under very high pressure. Sunlight does not reach that deep. Instead, there are special chemicals that give energy to small organisms. These organisms use a process called chemosynthesis. It is like photosynthesis, but it uses chemicals instead of sunlight.
Harsh Conditions
Life in
hydrothermal vents is not easy. The water is very hot and sometimes acidic. But
some organisms, called extremophiles, can live in these difficult places. They
have special adaptations that help them survive.
The Archaea Domain
Archaea are simple, very old organisms. They
live in hydrothermal vents. Scientists think they may have been the first
living things on Earth. DNA studies show that all life may come from a common
ancestor that lived in these vents.
Archaea are also similar to eukaryotes (cells with a nucleus). This means they
could be the ancestors of more complex life forms.
One idea is that life began with
Archaea. Later, some bigger cells ate smaller cells. The smaller cells did not
die—they lived inside the bigger cells and became parts of them. These parts
are called organelles. This idea is called the endosymbiotic theory.
It explains how simple cells (prokaryotes) changed into complex cells
(eukaryotes).
2. Ocean – a very big area of salt water that covers most of the Earth.
1. Primordial Soup Theory
The primordial soup theory says
that life began in the oceans a very long time ago, about 4 billion years ago.
In the water, there were many simple chemicals like carbon, hydrogen,
and nitrogen. With energy from the
Sun, lightning, or volcanoes, these chemicals mixed together like a “soup.”
Over time, they formed more complex molecules (like amino acids).
Later, these molecules joined to make the first simple living cells.
1. Life – The condition that makes animals and
plants grow and reproduce.
2. Machine – A tool or device that does a
job.
3. Molecule – A very small part of matter, made of
atoms.
4. Volcano – A mountain that can send out lava,
gas, and steam.
5. Spring – A place where water comes out of the
ground.
6. Ocean – A very large sea of salt water.
7. Vent – An opening that lets gas, air, or liquid
out.
8. Copy – Something that looks the same as the
original.
9. Primitive – Very simple, from an early
time.
10. Soup – A liquid food made by mixing things together.
11. Amino acids – The small parts that build proteins, important for life. Your body needs 20 different amino acids to function correctly. Essential amino acids can be found in a variety of foods, including beef, eggs, dairy.
12. Salt – A white substance we put in food, also in
the sea.
13. Glycerol – A sweet liquid that gives
energy.
14. Bacteria – Very small living things, some can
cause disease.
15. Replicate – To make the same thing again.
16. Divide – To split into two or more parts.
17. Cell – The smallest part of a living
thing.
18. DNA (Deoxiribonucleic acid)– A molecule in cells with the instructions
for life.
19. Blueprint – A plan or guide for making something.
20. Evolution – The slow change of living things
over time.
21. Thrive - To grow, flourish, or prosper.
22. Blast - An explosion.
23. Glow - To shine with a soft, steady.
24. To go bananas - Idiom that means to become very excited, angry.
ACTIVITY 2
Complete the text with the correct words:
ocean, volcanoes,
amino acids, DNA, bacteria.
Some scientists believe life began in the ______. Energy from the Sun and
______ helped simple chemicals form ______, which are the basis of proteins.
Later, these joined to make simple cells. Inside cells, ______ carries the
instructions for life. Tiny living things like ______ can divide quickly and
grow.
ACTIVITY 3
Match the word with its meaning:
1. Primitive ____ a) A mountain that can
send out lava
2. Volcano ____ b) Very simple, from an
early time
3. Cell ____ c) The smallest part of a
living thing
4. Vent _____ d) An opening that lets
gas, air, or liquid out
5. Amino acids _____ e) The small parts that build proteins
ACTIVITY 4
Put the events in the correct order (1–4):
____ Chemicals in the ocean formed amino acids.
____ Simple molecules mixed in the ocean like a soup.
____ Simple living cells began to replicate.
____ Life slowly evolved over billions of years.
