all things on earth fall into one of two categories: biotic: alive abiotic: not, and never has...
TRANSCRIPT
Matter and Energy in Ecosystems
All things on Earth fall into one of two
categories: Biotic: alive Abiotic: not, and never has been, alive
Biotic and Abiotic Factors
Identify five biotic and five abiotic factors in
Edgard.
Thought Question 1
Carbon can make long molecular chains and
rings It circulates through the biosphere
Carbon
All CO2 is circulated throughout all Earth
spheres constantly
Carbon Dioxide
About how much of the Earth’s atmosphere is
CO2?
Thought Question 2
Enters the
atmosphere through: Cellular
respiration Decomposition of
plants Eruption of
volcanoes Human actions,
like burning fossil fuels (coal, gas, oil)
The Carbon Cycle
Carbon is removed from the atmosphere by:
Plants and bacteria “fix” it into sugar molecules
Carbon Cycle continued
Draw a picture of diagram of the carbon cycle
on your own paper. Be sure to label each part of your picture.
Thought Question Picture
Why are scientists concerned about rising
levels of atmospheric carbon dioxide?
Thought Question 3
Also referred to as the hydrologic cycle It’s driven by the sun’s energy and
temperature differences on Earth
Solar energy and the water cycle
Essential
component of DNA, RNA and proteins
78% of our atmosphere is gaseous nitrogen, but most organisms cannot use it in this form
The Nitrogen Cycle
Lightning (5-8%)
Fixing nitrogen step 1
Imagine the beginning of life on Earth. How
important would lightning’s fixation of nitrogen have been at that time as compared with today?
Thought Question 5
The rest of the usable nitrogen is produced by
nitrogen-fixing bacteria. Most live in the roots of plants called
legumes, like soybeans, clover, alfalfa.
Fixing nitrogen step 2
Organisms cycle nitrogen through their bodies. Animals expel it with urine, where is
comprises part of ammonia and some proteins.
Fungi and bacteria degrade it so it stays in the soil and plants can use it, called denitrification.
Fixing nitrogen step 3
Humans can also fix it directly from the
atmosphere using manure.
Nitrogen fixation step 4
The nitrogen cycle includes nitrogen-fixing
bacteria, plants and animals that use nitrogen compounds; human industrial processes; and bacteria and fungi that convert nitrogenous compounds back into ammonia. Which of these could be eliminated without totally disrupting the nitrogen cycle? Explain your answer.
Thought Question 6
Photosynthesis and cellular respiration
Where does energy come from?
In which organelle does most cellular
respiration take place? Which kingdoms are able to do this (and what
word do we use to describe it)?
Recall Question
Who’s eating who
Trophic levels
Explain why the Sun is the ultimate source of
an opossum’s energy?
Thought Question 7
The basis of any
ecosystem They make their own
food through photosynthesis
Producers
Just eat the producers
Primary consumers
Animals that eat
primary consumers
Secondary consumers
Animals that eat both
primary and secondary consumers
Tertiary consumers
Think of a grassland ecosystem. Name one
example of a producer, a primary consumer, and a secondary consumer in that ecosystem.
Thought Question 8
Matter moves in
cycles, but energy moves up the trophic pyramid in one direction.
It also drains as it moves from life form to life form.
The movement of energy
Only about
10% of the energy that enters a trophic level is available to the trophic level immediately above it.
Depicted in a trophic pyramid.
The 10% rule
Suppose that a field of blackberries absorbs
400,000,000 kJ of sunlight. According to the ten percent rule, how much of the original energy is available to…
…mice that eat the berries? …snakes that eat the mice? … owls that eat the snakes?
Thought Question 9
Explain why a grassland can sustain many
more mice than snakes.
Thought Question 10
A food web is a
model that shows energy flow in an ecosystem.
Keys: Arrows points from
an organism to what eats it
It shows that energy is moving from one thing to whatever it’s pointing at
Food webs
Suppose that
the worms in this ecosystem were to disappear. Describe at least 2 effects that the worm’s disappearance would have on other populations.
Thought Question 11
Watch the video and complete the trophic
levels pyramid with the animals you see.
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