- Earth provides conditions suitable for life, including being the right distance from the Sun, a gaseous atmosphere, and a protective magnetic field. - All living things share similar characteristics including nutrition, interaction with their environment, and reproduction. Nutrition involves obtaining energy and matter from the environment or other organisms. Interaction requires adaptation to the environment. Reproduction creates new living things. - Through experiments, scientists determined that living things always come from other living things and living organisms do not spontaneously generate from nonliving matter.

1. IV LIVING THINGS
Earth a living planet.
Our planet is a perfect distance from the Sun to be warm. Our planet has enough mass
to hold gaseous of atmosphere. Our planet has a magnetic field that protects us from
dangerous radiations. We are lucky; life is possible on our planet.
A1: In the following video look for ideas that you haven’t read on the previous
paragraph. What else do living things need?
http://www.youtube.com/watch?v=1zCQ7QM3CZU
All of us have an intuitive idea about what is alive and what is inanimate or lifeless, but
sometimes we have wrong ideas about what is alive.
A2. Watch the following picture and choose which of them represent living things.
A3. Now you should think about your reasons to decide what things are alive or
inanimate.

2. A4: Which processes enable living things to …
• Create new living things
• Adapt to their environment
• Obtain the energy they need
A5: The coal that we use in a barbecue is made of carbon. Do you think coal is a living
thing?
A6: Out of the following substances, which are living things?
o Flower
o Meat
o Worm
o Cow
o Cloud
o Leaf of a plant
o Kidney
LIVING THINGS
It is not easy to establish boundaries between life and nonlife, scientists are still
arguing about these ideas, but there exists an agreement on three concepts based on
what living things do:
• Nutrition: refers to all the processes, which enable living things to obtain
energy, and matter they need to live.
• Interaction with the environment: Animals and plants are affected by their
environment. Living things depend upon their environment for their survival.
• Reproduction: refers to all the processes that enable living things to create
new living things.
All living things have a similar composition; about 95% of living things are made of
“O” oxygen, “C” carbon, “H” hydrogen.
Remember: A living being is made mostly of water and organic substances (made of
“C” carbon, “O” oxygen and “H” hydrogen). A living being is able to do the three
following functions:
• Nutrition
• Interaction with the environment
• Reproduction.

3. Every living thing is produced from another living think
A7: Perhaps you have seen a dead animal in the countryside and you have probably
seen maggots on its body. Where did the maggots come from?
In the XVII century many scientists thought that some organisms appear by
spontaneous generation. They thought that living organisms could arise spontaneously
from nonliving matter. Francesco Redi (1626 – 1698) tried to test this idea with the
experiment below:
A8: Why do you think about flies, maggots and eggs appear in the first jar and don’t
appear in the other two?
In spite of this fact, after some time, when you remove the lid from the jar the meat
smells bad and it is putrefy because of microorganism.
Unfortunately, Redi’s experiment did not convince everyone. Some argued that while
spontaneous generation might not apply to larger organisms like maggots and flies, it
might still be applicable to smaller microbes.
Louis Pasteur finally answered the question definitively in the late 1800s, in his now
classic experiment. Pasteur boiled the sample to kill any existing organisms, days later
he removed the lid from the jar and checked for growth of any organism. Pasteur didn’t
use meat he used as sample broth.
http://www.pasteurbrewing.com/The-Life-and-Work-of-Louis-
Pasteur/experiments/Redi-Louis-Pasteur-and-Spontaneous-Generation-for-Kids.html
A9: Do you think it would be possible for a living organism to arise from nonliving
things?

8. Some ideas to help you!!
Nutrition
Autotroph: focused on plants?
• How do the plants make their own food?
• Photosynthesis. Sun's energy.
Chemical reaction.
Heterotrophs: focused on animals.
• Carnivores
• Herbivores
• Omnivores
Food energy chain

9. Interaction with environment
Animals and plants are adapted to the habitat
• Cactus plants live in dry habitats. Their leaves are sharp spines
• What is hibernation?
• We notice the weather is getting colder in winter and we put on warmer clothes.
But how do animals and plants survive this changes
In this case, is the man
adapted to the
environment?

10. Reproduction
Sexual
reproduction
Asexual reproduction
Some organisms like bacteria reproduce using binary fission. They split in two, so one
bacterium becomes two bacteria. This always leads to daughter cells, and the offspring
will be identical to the parent.
The baby has genetic information
from both