5. As the name might suggest, life science studies life in all its forms,
past and present. This can include plants, animals, viruses and
bacteria, single-celled organisms, and even cells. Life sciences study
the biology of how these organisms live, which is why you may hear
this group of specialties referred to as biology.
As you might expect, with an estimated 8.7 million species of
animals, about 400,000 species of plants, and countless species of
bacteria and viruses, there are a lot of different forms of life you can
study. Many life science researchers specialize in one class or
organism, and some specialties such as zoology have even more
subspecialties. There are more than thirty different branches of life
sciences, but we’ll review some of the major branches here.
www.Artifactsresearchrecognition.com.
6. How Life Began
The universe is about 4.6 billion years old. The formation of the Earth
along with other planets of our solar system is believed to have
occurred some 4.5 billion years ago. Life on Earth, however, probably
began only between 3.5 and 4.0 billion years ago. The important
question is how was life first formed.
Evidence from fossil records show that the oldest fossil resembled the
one- celled organism like bacteria.
7. GUIDE QUESTIONS
1. What is the video all about?
2. What is Life?
3. Why humans are so special?
8. HOW DID LIFE ON EARTH BEGIN?
FOR SOME THEN THE ORIGIN OF LIFE COULD
BE EXPLAINED BY THE SPONTANEOUS
GENERATION THEORY WHICH STATES THAT
LIFE FORMS CAN BE GENERATED FROM
INANIMATE OBJECTS. THIS BELIEF HAD BEEN
AROUND SINCE THE TIME OF ARISTOTLE.
Francesco Redi Lazaro Spallanzani Alexander I Oparin Stanley I. Miller
9. Francisco Redi was able to disprove the spontaneous generation theory
when he experimented by placing meat in all the jars, but covered four of the jars
with muslin. Maggots developed in the open jars but did not develop in the muslin
– covered jars.
In the late 1700’s likewise tried to disprove the spontaneous generation
theory by performing a controlled experiment with broth. He put broth into two
flasks ( glass containers) and sterilized them both by boiling the broth. One of the
flasks was left open to the air. The other flask was sealed up to keep out any
organisms developed only in the uncovered flask. From his, Spallazani concluded
that: 1 the microorganism's did not come from the broth , but were in the air that
entered the flask; 2 therefore, not even microorganisms came from non-living
things.
10.
11. In the late 1700’s likewise tried to disprove the spontaneous
generation theory by performing a controlled experiment with broth.
He put broth into two flasks ( glass containers) and sterilized them
both by boilinh the broth. One of the flasks was left open to the air.
The other flask was sealed up to keep out any organisms developed
only in the uncovered flask. From his, Spallazani concluded that: 1 the
microorganisms did not come from the broth , but were in the air that
entered the flask; 2 therefore, not even microorganisms came from
non-living things.
12.
13. In 1953, Alexander I Oparin, a Russian scientist
hypothesized that the atmosphere of primitive earth
contained gases like ammonia, methane, hydrogen and water
vapor. He explained that energy of lightning and ultraviolet
rays from chemical compounds. As they mxed with rain and
hot seas, they formed complex organic molecules which was
similar to what living things Lazaro Spallanzani are made of.
14.
15. An American scientist , Stanley I. Miller performed an experiment
using a mixture of the glass suggested by Oparin. He introduced
electrical sparks into the mixture. After a few days, molecules similar
to amino acids that are found in all living things were formed. His
expirement proved that the first organic molecules could have been
formed from the primitive earth. Living cells may arisen on early
earth through a series of chemical combinations of these organic
compounds.
16.
17. LT 1: ACTIVITY 1:GRAPHIC ORGANIZER
Directions: Make a simple graphic organizer of a unifying theme in the
study of life that shows the connections among living things and how they
interact with each other and with their environment
