Principles of Ecology: Matter, Energy, and Life

1
Principles of EcologyMatter, Energy, and Life
Ecosystems

• BSC 1050 Environmental Conservation
• Professor Pamela L. Pannozzo
• Lecture 3

2
Ecosystems and Ecology

• Ecosystem the abiotic environment and the
  organisms that live there
• Ecology The study of the interactions of the
  biotic and abiotic environment

3
The Importance of Trees
4
Characteristics of Ecosystems

• Processes
• Biogeochemical cycling (closed system)
• Energy flow (open system)
• Structure
• Habitat created by both physical environment and
  living things
• Energy flow through food webs
• Change
• Succession

5
Ecosystem Processes

• Biogeochemical Cycles (closed system)
• Energy Flow (open system)
• All energy of living things comes from the Sun
• Sun to Earth ? plants (converted to chemical
  energy) ? transferred to animals and among
  animals ? dissipates as heat ? energy returns to
  the Universe

6
Sunlight

• Sun ball of exploding hydrogen gas
• Produces electromagnetic radiation
• Classified by wavelengths as a spectrum
  (electromagnetic spectrum)
• Intense energy short wavelengths
• Lower energy long wavelengths

7
Electromagnentic Spectrum
8
Electromagnetic Spectrum
9
Visible Light

• Most energy reaching Earth is in wavelengths 400
  to 700 nm (visible light)
• Visible light wavelengths absorbed by plant
  pigments ? drive photosynthesis

10
Photosynthesis

• 6H2O 6CO2 sunlight energy ? C6H12O6
  (chemical energy) 6O2

11
(No Transcript)
12
(No Transcript)
13
Cellular Respiration

• C6H12O66O2 energy ? 6H2O 6CO2 ATP
  (chemical energy)

14
Energy Exchange
15
Food Webs and Trophic Levels

• Biomass biological material
• Productivity amount of biomass produced in a
  given area during a given time
• Food Webs interconnected food chains in an
  ecosystem
• Trophic Level an organisms feeding position in
  an ecosystem

16
Ecological Food Web
17
Trophic Levels

• Organisms classified by the kinds of food they
  consume for energy
• Producers/Autotrophs Obtain energy from abiotic
  sources
• Photoautorophs - photosynthesis
• Chemoautotrophs chemical cources
• Consumers (primary, secondary, tertiary)/Heterotro
  phs Obtain energy from biotic sources
• Herbivores - Eat plants
• Carnivores - Eat animals
• Omnivores - Eat plants and animals
• Detritivores - Eat detritus
• Decomposers Break down complex organic matter
  into simpler compounds

18
(No Transcript)
19
Ecological Pyramids

• Huge number of primary producers needed to
  support smaller number of herbivores ? support
  smaller number of secondary consumers
• Heat energy lost with each transfer (second law
  of thermodynamics)
• 10 Rule

20
(No Transcript)
21
Ecosystem Structure

• Populations
• How dense is the population?
• How is the population dispersed?
• Factors Affecting Populations
• Birth, death, emigration, and immigration rates
• Competition
• Predation
• Symbiosis

22
Competition

• What do individuals compete for?
• food, shelter, water, mates, social interaction,
  protection
• Competition for resources may be within species
  and/or between species
• How many individuals can the environment support?
• Biotic Potential vs. Carrying Capacity

23
(No Transcript)
24
(No Transcript)
25
Ecological Niche

• Habitat where a species lives
• Ecological Niche role played by a species in a
  biological community
• Niche types
• Generalists - broad niche (raccoons)
• Specialists - narrow niche (panda, koala)
• Opportunists generalists (rats, pigeons)
• Pioneer species disturbance (lichens, weeds)
• Competitive Exclusion Principle complete
  competitors cannot coexist
• Recourse partitioning enables individuals to
  avoid competition

26
(No Transcript)
27
(No Transcript)
28
Predation

• Predator - any organism that feeds directly on
  another living organism
• Herbivores, carnivores, omnivores, parasites,
  pathogens
• Influences on population balances
• Stages of predator and prey life cycles
• Specialized food-obtaining mechanisms
• Specific predator-prey adaptations
• Coevolution (plants-pollinators)

29
(No Transcript)
30
Symbiosis

• Symbiosis - Intimate living together of members
  of two or more species
• Commensalism - One member benefits while other is
  neither benefited nor harmed
• Cattle and cattle egrets, Spanish moss and Live
  oak trees
• Mutualism - Both members benefit
• Lichens (Fungus and cyanobacterium)
• Parasitism - One member benefits at the expense
  of other
• Humans and tapeworms

31
Ecosystem Structure

• Communities
• Which species live in this ecosystem?
• In what ways do these species interact?
• Characteristics of Communities
• Diversity
• decreases when moving from the equator to the
  poles
• Abundance of species
• Complexity
• Number of species at each trophic level, and
  number of trophic levels
• Complex communities more stable and resilient in
  the face of disturbance

32
How Are Communities Organized?

• Vertical or horizontal distribution (forests,
  oceans)
• Types
• Randomly Arranged
• Individuals live wherever resources are available
• Clumped
• Individuals cluster together for protection,
  assistance, or resource access
• Regularly Arranged

33
Factors Affecting Community Structure

• Resource availability,
• Fire
• Competition
• Predation
• Symbiotic relationships
• Keystone species

34
Keystone Species

• Keystone Species species with major impact on
  system
• Gopher tortoises, alligators, beavers
  (environmental architects)
• Mycorrhizae (nutrient mobilization)
• Tropical figs (fruiting season)

35
Ecosystem Structure

• Succession
• process by which organisms gradually change
  environmental conditions at a site by creating
  soil, shade, shelter, humidity, etc.
  (facilitation)
• increases diversity
• Primary Succession - pioneer species
• Secondary Succession
• Climax Community - resists further change

36
(No Transcript)
37
Invasive Exotic Species

• Out-compete native populations, alter nature of
  the community
• Predator-prey relationships
• Abundance
• Diversity
• Resilience/stability