1. Chapter 3 ~ An Introduction to Ecology and the Biosphere
I am the Lorax.
I speak for the trees.
I speak for the trees,
for the trees have no tongues.

2. Ecology Biosphere ~the parts of the planet where life exists
Species ~group of organisms that can breed and produce fertile offspring
Population ~group of individuals of the same species in a particular geographical area
Community ~assemblage of populations of different species
Ecosystem ~all non-living factors and the collection of organisms in a particular place
Biome ~a group of ecosystems that have the same climate and similar communities.

5. Relationships, I
Primary producers/autotrophs~ the trophic level that supports all others
Photosynthetic – use sunlight
Chemosynthetic – use inorganic compounds
Consumers/heterotrophs – rely on other organisms for their energy and food supply
Primary consumers~ herbivores: eat only plants
Secondary and tertiary consumers~ carnivores: eat animals omnivores: eat plants and animals
Detrivores ~special consumers that derive nutrition from non-living organic matter
Decomposers: bacteria and fungi that break down organic matter

6. Relationships, II
Food chains ~a series of steps in which organisms transfer energy by eating and being eaten
Food webs ~ interconnected feeding relationships in an ecosystem
Trophic structure / levels~ feeding relationships in an ecosystem

7. Energy Flow in an Ecosystem
Energy flows in one direction
through an ecosystem, from the sun
(or inorganic compounds) to producers through various levels to consumers.

8. Energy Flow in an Ecosystem
– the ability to do work
Behavior described by:
1st Law of Thermodynamics
Energy may be transformed from one type into
another but is never created or destroyed.
2nd Law of Thermodynamics
States that when energy is transferred or
transformed, part of the energy assumes a form
that can not pass on any further.

9. Energy Flow
Ecological efficiency: % of E transferred from one trophic level to the next (5-20%)
Pyramid of productivity: multiplicative loss of energy in trophic levels
Biomass pyramid: trophic representation of biomass in ecosystems
Pyramid of numbers: trophic representation of the number of organisms in an ecosystem

10. Ecological Pyramids Section 3-2 Energy Pyramid
Shows the relative amount of
energy available at each trophic
level. Organisms use about 10
percent of this
energy for
life processes.
The rest is lost
as heat.
Pyramid of Numbers
Shows the relative
number of individual
organisms at each
trophic level.
Biomass Pyramid
Represents the amount of
living organic matter at each
trophic level. Typically, the
greatest biomass is at the
base of the pyramid.

11. Chemical Cycling
Biogeochemical cycles: the various nutrient circuits, which involve both living and non-living components of an ecosystem
Water
Carbon
Nitrogen
Phosphorus

12. The Water Cycle The Water Cycle Section 3-3 Condensation Precipitation
Transpiration
Evaporation
Runoff
Seepage
Root
Uptake

13. The Carbon Cycle Figure 3-13 The Carbon Cycle Section 3-3 CO2 in
Atmosphere
CO2 in Ocean

14. The Nitrogen Cycle Figure 3-14 The Nitrogen Cycle NO3- and NO2- NH3
Section 3-3
N2 in Atmosphere
NO3-
and NO2-
NH3

16. Nutrient Limitation
Primary productivity- the rate at which organic matter is created by producers
Controlled by the amount of available nutrients
Limiting nutrients: a nutrient that is scarce or cycles slowly in an ecosystem

17. Eutrophication:
increase in nutrients, especially nitrogen and phosphorus
promotes plant growth, favoring certain species over others
forcing a change in species composition.
in aquatic environments, enhanced growth (algal bloom) disrupts normal functioning of the ecosystem.