Download lecture 9/21, ecology III, ecol. pyramid

Ecology III
ES101 9/21/10
Tutor – HIGHLY RECOMMENDED!
Frangelica Odell, M&W, 6-8pm, MH201
• reading Qs due Thurs.; forest lab due next Wed.
Ecology III
ES101 9/21/10
Tutor – HIGHLY RECOMMENDED!
Frangelica Odell, M&W, 6-8pm, MH201
• reading Qs due Thurs.; forest lab due next Wed.
• Exam 1 is two weeks from today
- Will be a combination of mult. choice and essays.
- We will use some of the clicker questions from
the next several lectures (including today!) on the
exam.
Matter and Energy
• Matter = anything that has volume and mass
• Energy = ability to do work
• Kinetic energy (k.e.) = energy in anything that
moves (includes light waves, heat, etc.)
• Potential energy (p.e.) = stored energy
• Chemical p.e. = energy stored in the bonds of
molecules
• Gravitational p.e. =
energy stored in something that can fall
Laws of Thermodynamics
• Thermodynamics = how energy is transferred
• First Law: Energy is conserved = can’t create or
destroy energy
• Can move it around and change forms
(kineticchem. p.e., etc.)
Food = Chem. p.e.
Food + oxygen = releases stored energy
Allows motion in body = Kinetic p.e.
http://themostawesomeststuffever.blogspot.com/2008/07/happy-fourth-of-july.html
Laws of Thermodynamics
• Second Law: Every time energy is moved or
transformed, some energy is released as heat
• Heat is a low quality form of energy – hard to
use it to do work
• Need to do work to keep
order in universe
• Entropy (=disorder)
in universe is increasing
Ex: Brick wall; clean room; both
need energy to stay organized
Second Law Example
• Car engine
• Gas is concentrated
chem. p.e.
• Converted to motion
of car
• Heat, gases are also
released
• <20% of gas energy
becomes motion –
rest is wasted!
http://www.chemistryland.com/CHM107/Energy/Energy.html
A little chemistry…
• Molecule = 2 or more atoms bonded together
• Organic molecule = large, complex with lots of
carbon
• Ex. C6H12O6 glucose
• Inorganic molecule = usually smaller, little or no
carbon
• Ex. NO3= nitrate, NH3 = ammonia,
CO2 = carbon dioxide
Energy for life
• All life needs energy
• Producers: Species that capture own energy.
Use:
– Chemosynthesis: Inorganic chemicals used
as energy sources (not very common) OR
– Photosynthesis: Sun used as energy source
• Consumers: Species that eat other life forms to
get energy
All of the energy in all of the food you eat
ultimately began with
1. an animal eating a
plant
2. a plant growing
somewhere
3. the sun
4. fossil fuels
92%
0%
1
4%
2
4%
3
4
Photosynthesis
Carbon dioxide + Water + Light energy 
Glucose (stored energy) + Oxygen + heat
• Biomass = living weight = a measure of
energy stored
• More plant growth, more biomass
• Reverse is respiration – production of useful
energy from stored energy:
Glucose (stored energy) + Oxygen 
Carbon dioxide + Water + energy + heat
1st Law of Thermod Conservation of Energy:
• How is it demonstrated
in a Food web?
• energy moves around
and changes forms, but
is not created or
destroyed.
Top carnivores
Primary carnivores
Herbivores
Producers
sun
2nd Law of Thermod. – Ecosystem example:
Drawing of energy in plants, herbivores, carnivores;
size of box = amt of energy
2nd Law of Thermod. – Ecosystem example:
Ecological Pyramid =
• most energy (measured as biomass) in
ecosystem is in plants; less energy as you go
up food chain.
• Energy lost to heat and waste, not converted to
new biomass
http://www.sturgeon.ab.ca/rw/Pyramids/pyrakind.html
Ecological Pyramid =
• Energy lost to heat and waste, not converted to
new biomass
• top predators are rare because need a lot of
animals, land area, to support them
• Explains why can feed more people on a
vegetarian diet than a meat diet –
meat requires more food, energy, land.
http://www.sturgeon.ab.ca/rw/Pyramids/pyrakind.html
• Explains why can feed more people on a
vegetarian diet than a meat diet –
meat requires more food, energy, land.
• Takes 16 lbs of plant to make 1 lb of beef
Which of the following groups has the most total
biomass in an ecosystem?
1.
2.
3.
4.
omnivores
plants
herbivores
carnivores
85%
13%
2%
1
0%
2
3
4
Nutrient cycles
• Energy flows in one direction – towards disorder
– life requires energy from sun
• Nutrients can go in a cycle
• Nutrients – elements needed for life
• Macronutrients – need A LOT:
• Carbon: Backbone of organic molecules;
carbohydrates, fats, sugars, etc
• Nitrogen: Amino acidsproteins; enzymes; DNA
• Phosphorus: DNA; Cell membranes
According to the best scientific evidence, which of
the following is the main cause of recent changes
in the earth’s climate?
1.
2.
3.
4.
sun spots
ocean currents
ozone depletion
the greenhouse
effect
5. all of the above
48%
33%
17%
2%
1
0%
2
3
4
5