Transcript Existence of Life

Existence of
Life
Class Notes
Goldilocks & the 3 bears
○ Remember
the story of Goldilocks & the 3
bears.
○ Think about what the words “just right”
meant.
○ What
are some conditions
that are “just right” on Earth
to allow life to exist?
Cornell Notes
Title: Existence of Life
Topic/Objective: TEKS 7.9A
Analyze the characteristics of objects in the
Solar System that allow life to exist.
Essential Question 1: What characteristics
are needed for life to exist?
Just Right….
○A
habitable planet has abiotic factors
(non-living) and characteristics that are
just right for allowing life to exist.
○
Earth is the only known planet at this time.
What makes Earth “just right”?
○
Draw and label a diagram of the planets going across
your paper in order with the sun on the left.
Sun
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Earth is in just the right location for life to exist (not too hot, not too cold)!
Characteristics that Allow Life to Exist:
1. Temperature
○
○
○
Life is limited to a temperature range of
-15°C to 115°C.
Because of its distance from the sun,
Earth has a temperature range of 0°C
to100°C, which allows life to exist.
The length of day and night also
contribute to temperatures that can
sustain life.
2. Presence of Liquid Water
Earth’s temperature range allows water to
exist in liquid form.
○ 0°C is the freezing point of water and
100°C is the boiling point of water.
○ Water is regularly available.
○ Landforms allow water to run from high to
low elevations and replenish as the
seasons change.
○
3. Composition of Atmosphere
○
○
○
The Earth’s atmosphere thickness traps heat & protects it
from the Sun’s harmful UV radiation.
It also protects it from small to medium sized meteorites.
It contains gases including nitrogen, oxygen, argon, &
carbon dioxide. (NOArCo2)
4. Energy Source
○
○
With a steady input of either light or chemical energy
from the sun, cells can perform the chemical
reactions necessary for life (photosynthesis).
These give us food sources including plants and
animals.
5. Nutrients
○
○
All solid planets and moons have the same general
chemical makeup so nutrients are present.
Planets with a water cycle or volcanic activity can
transport and replenish the chemicals required by living
organisms (vitamins).
Essential Question 2:
Why is Earth the perfect location for life to exist?
○The temperature is not too hot and not too cold
(length of day and night)
○Water can exist in liquid form, many sources available
○Atmosphere has needed gases for living things
○Sun provides energy so plant cells can carry out
photosynthesis
○Earth has nutrients necessary for life to exist
Review Questions
1. What characteristics are needed for life
to exist?
2. Why is Earth the perfect place for life to
exist?