Download matter, energy, and Life PPT

MATTER, ENERGY, AND LIFE
Chapter 3
Let’s first review some older material…
Energy!

All living systems absorb energy from their
surroundings and use it to organize and reorganize
molecules within their cells & to power movement.
Forms of energy

Basic Unit of energy = Joule (J) = amount of
energy used when a 1-watt light bulb is turned on
for 1 second
Kinetic and Potential Energy


Potential energy = Stored energy
Kinetic energy = energy of movement.
First Law of Thermodynamics


Energy is conserved.
Just as matter can neither be created nor
destroyed, energy is neither created nor
destroyed.
Second Law of Thermodynamics

When energy is transformed, the quantity of energy
remains the same, but its ability to do work diminishes.
Energy within a system


Open Systems – exchanges of
matter/energy occur across system
boundaries
Closed systems – matter/energy
exchanges do not occur across system
boundaries.
Feedback Loops
Ecosystem Ecology
Ecosystem Boundaries


Ecosystems are composed of biotic and abiotic
components that interact with one another.
Ecosystems interact with other ecosystems through
the exchange of matter and energy.
From species to ecosystems
Organism
• An
individual
living
thing
Population
• All the
members of
a species
living in a
given area
at the same
time
Community
• All
populations
living &
interacting in
a given
area.
Ecosyste
m
• Composed
of a
biological
community
and its
physical
environment.
Energy Flow:
Photosynthesis
& Cellular
Respiration
Trophic Levels, Food Chains, and Food
Webs

Trophic Levels
 Producers
– autotrophs such as algae or plants.
 Primary consumers – heterotrophs that consume producers
 Secondary consumers – heterotrophs that consume
primary consumers
 Tertiary consumers – Heterotrophs that consume
secondary consumers

The sequence of consumption from producers to tertiary
consumer is the food chain.
Food Webs




Not all organisms fit into one trophic level.
Scavengers are carnivores that consume dead
animals.
Detritivores are organisms that specialize in
breaking down dead tissue into smaller particles.
Decomposers complete the breakdown process by
recycling the nutrients from dead matter back to the
ecosystem.
Trophic Pyramids



Biomass is the total mass of all living matter in a specific
area.
Not all the energy in a trophic level is in a usable form.
(Only about 10% ecological efficiency)
Why is there so much less energy in each trophic level?
 Undigested
food
 Daily bodily processes
 Lost as heat