Transcript Life on Earth

Life on Earth
and nowhere else…
Describe the perfect place to
grow a plant.
What makes it grow well?
Now, compare this to Earth.
What makes Earth the perfect
place to live?
The Goldilocks Zone
 Earth’s life-sustaining
conditions are possible
because of its position
in the solar system
 It is not too hot and
not too cold – if the
Earth was any closer
or further away from
the Sun, the planet
could not support life
Other Life Sustaining
Conditions
 Earth’s rotation on its axis and orbit
around the Sun helps distribute heat
evenly around the planet
 Earth’s magnetic field protects the
planet from deadly radiation and
particles
 Earth’s gravitational field holds the
atmosphere in place preventing
oxygen, nitrogen, and carbon dioxide
from escaping into space
Four Conditions for Life
1.Stable Temperature Range
2.The Importance of Water
3.The Importance of Gases
4.The Role of the Atmosphere
Stable Temperature Range
 A stable temperature range (-50 to about +50
degrees Celsius) allows life to thrive – the
average temperature has been between 10-20
degrees Celsius for 3.5 billion years
 The greenhouse effect allows for heat in the
atmosphere (carbon and water vapor) to be reradiated back to Earth
 Without proper water and carbon, the earth
would be -73 degrees C.
The Importance of Water
 First water likely came from volcanic activity – water collected
on the cooling surface and as vapour in the atmosphere
creating the water cycle
 Biologists believe earth first began in the oceans – blue-green
algae
 Oceans cover 2/3 of the Earth – absorbs heat and distributes it
around the world and controls our weather patterns and
climates
 Helps distributes nutrients to plants
and other organisms
 No living thing consists of less than
50% water
 Water is the metabolizing agent that
allows plants and animals to dissolve
minerals and nutrients to create
energy
The Importance of Gases
 78% nitrogen, 21% oxygen, carbon dioxide 0.03% quite different than other planets in the solar system
 The plants have removed most of the carbon dioxide
that originally existed and produced lots of oxygen
 Without life on earth, carbon dioxide would increase
 The production of carbohydrates, fats, and proteins
require oxygen, carbon, and nitrogen atoms from
the atmosphere, and hydrogen from water
The Role of the Atmosphere
 Layer of gases about 80-100 kms thick – very thin
compared to size of Earth
 Helps maintain a consistent temperature
 Shields earth from collisions with cosmic particles
(meteors)
 Oxygen levels at 21 allow for life, if they drop,
animal life would not be possible, if it exceeds 25%
most plants would be consumed by fire
 Oxygen is produced by plants and consumed by
animals and the burning of plants and fossil fuels
So, why can we not live on other
planets?
Let’s find out!
Time for Teamwork!
 Each group will be responsible for collecting
information about an assigned planet.
 You will use the information provided to
complete the “Planet Exploration” sheet with
your group.
 You will have 15 minutes to complete this task.
 Every member of your group must have all of
the important information recorded.
Finding Earth’s Mate
(aka match.com)
 Now that you have become an expert on a particular planet, it’s time
to find out about all of the others.
 Our mission today is to find the planet that is most similar to Earth.
Would it be possible to live on any of these other planets?
 You will have 15 minutes to move around the room seeking out
potential candidates to be Earth’s mate.
 You will use the “Finding Earth’s Math” handout to record the
information that you collect.
 Find someone representing a planet other than yours. Exchange
information with that person, and then seek out another planet.
 Repeat this process until your entire sheet is filled.
 Once your sheet is filled, return to your seat, and analyze your data.
Which planet could be Earth’s mate?