Ecology-questions to answer
following presentation slides
Part 1 (17-1 text)
•  1. What is your habitat?
•  2. What do ecologists study?
•  3. How does a pond community differ
from a pond ecosystem?
•  4. How do biotic and abiotic factors
differ?
•  5. What does it mean to have a diverse
community?
Ecology
The study of interaction of
living organisms and their
environment
Habitat
Where an organism lives
ex. Where do you live? A house, an
apartment, a condo?
Community vs. Ecosystem
•  All the organisms
interacting in a
habitat make up a
community
•  All the organisms
interacting with
each other and
their environment
in a habitat form
ecosystems.
http://www.forests.unimelb.edu.au/images/mixed%20species%20forest_forest
%20ecosystems.JPG
Habitats
•  Abiotic factors- physical aspects of
habitat, e.g. water, minerals, air, sun
•  Biotic factors- living organisms of a
habitat
Biodiversity
= Number of species
living in an ecosystem
A healthy ecosystem
has high biodiversity.
Meaning - many types
of organisms live there
and in large numbers
What is the most diverse
ecosystem?
Part 2: 17-2 Questions
•  6. What is succession?
•  7. How do primary and secondary
succession differ?
•  8. What is succession in lakes called?
•  9. How do we speed up the natural
process of lake succession?
Succession
•  A progression of species replacement.
Succession
•  Primary- where growth has not
previously occurred, e.g. glacial
retreat
•  Secondary- where growth has
occurred, e.g. forest clearings
•  Pioneer species- the first
species to re-colonize after a
disturbance, e.g. lichens, moss,
fireweed
Mt. St. Helens
Succession
Humans affect succession
•  Lakes, ponds and streams naturally age
and change over time.
•  We add excess nutrients (fertilizers) and
allow soils to wash into water which
speeds up this process of aging.
–  Eutrophication is the natural aging process
or succession in a lake
•  Human caused aging is called cultural
eutrophication and can cause a rocky bottom,
high dissolved oxygen lake with nice clear
water to change into a scummy pond
17-2 Energy Flow in
Ecosystems Questions
•  10. What is the primary source of energy for earth?
•  11. What other source of energy can start a food chain?
•  12. All organisms need energy to survive. How do producers
vs. consumers get their energy?
•  13. How do food webs and food chains differ?
•  14. Why are food webs a more accurate view of communities?
•  15. Why are communities with complex, diverse food webs more
stable?
•  16. What do the following eat:
•  a. herbivores
d. Scavengers
•  b. carnivores
e. decomposers
•  c. omnivores
Questions for 17-2 con’t
•  17. A diagram that shows the energy available at each trophic
level is called a ____________________.
•  18. How much energy is generally lost at each step in a food
chain?
•  19. What happens to the number of organisms as you get higher
up on food chains?
•  20. If we want to be able to feed the growing world population
should we be eating more or less meat? Explain.
21. Create Your Food Web
•  Create a food web that includes you,
specifically.
•  What did you have for lunch today/
yesterday?
•  Include at least 8 organisms (some
producers, consumers and
decomposers) and draw arrows to show
the energy exchange, label trophic
levels
Where do living things
get their energy?
•  It all starts with the
sun!
–  Exceptions exist
such as
•  bottom of the ocean
where there is no
sunlight near black
smokers
•  food chains start with
chemosynthesis
using sulfur taken in
by bacteria
How do you get your energy?
•  Producers- produce
their own energy
through photosynthesis
•  Consumers- eat plants
and other animals for
energy
http://neuromanagement.files.wordpress.com/2009/03/food-chain.jpg
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPS.html
Food Webs
•  Show interconnected
food chains
• Organisms feed at many
trophic levels
• Diet sometimes changes
as mature and grow
• Complex food webs
mean healthier more
stable communities
because if one member is
lost the whole thing is less
likely to fall apart.
Roles in a Food Chain/Web
* also called Trophic Tevel
•  Producers – make their own food
•  Herbivores (primary consumers) eat plants
•  Carnivores (secondary or tertiary
consumers) eat animals
•  Omnivores (secondary or tertiary
consumers) eat plants and animals
•  Detritovores get energy from dead
organisms (also called scavengers)
•  or decaying organic waste (also called
decomposers = bacteria and fungi)
Now make your own Food Web including at
Energy Tranferred through the Trophic
Levels is shown in a Energy Pyramid
•  Most is lost as heat into
the atmosphere with
each energy transfer
–  Only 10% of the plant’s
energy ends up in the
herbivore
–  Only 10% of the
herbivore’s energy ends
up in the carnivore
Each trophic level supports
fewer organisms as less
and less energy is
available
http://www.mesa.edu.au/friends/seashores/images/energy_pyramid.gif
Energy Flow in an Ecosystem
Energy Pyramid
At each trophic level, the energy stored is 1/10 of the
Energy stored by the organisms in the level below.
Top carnivores
Carnivores
Herbivores
.05%
Producers
50%
.5%
5%
Energy Efficiency
in Food
Consumption
•  Energy is lost
through the
trophic levels