1. Fundamentals of Ecology
Chapter 2
Fundamentals of Ecology

2. Unit Objectives Define ecology
Define ecology
Differentiate between biotic and abiotic
Differentiate between habitat and niche
Define homeostasis
List and define the physical factors influencing the aquatic environment
List the factors that influence the distribution of species

3. Unit Objectives Understand the flow of energy in marine systems
Understand the flow of energy in marine systems
Differentiate between a food chain and a food web

4. A. Study of Ecology 1. Environment
1. Environment
a. biotic factors
b. abiotic factors
2. Habitat: where an organisms lives

5. Study of Ecology 3. Niche: an organism’s “role” in the environment
3. Niche: an organism’s “role” in the environment
environmental factors
biological factors
the organism’s behavior

7. Environmental Factors Affect Organism Distribution
Maintaining homeostasis
homeostasis and the distribution of marine organisms
optimal range
zones of intolerance

9. Environmental Factors Affect Organism Distribution
Physical environment
sunlight
photosynthesis
vision
desiccation
temperature
ectotherms
endotherms

10. Environmental Factors Affect Organism Distribution
salinity
solutes
osmosis
solutes in the body fluids of organisms
regulation of solutes in body fluids

12. Environmental Factors Affect Organism Distribution
pressure
760 mm Hg (14.7 psi) or 1 atmosphere at sea level
increases 1 atmosphere for every 10 meters below sea level
Ex: Every 33 ft pressure increases another 14.7psi
60 miles of air creates pressure that is equivalent to 33ft. of seawater

13. Environmental Factors Affect Organism Distribution
metabolic requirements
nutrients and limiting nutrients
oxygen as a requirement for metabolism
anaerobic and aerobic organisms
eutrophication and algal bloom
metabolic wastes
carbon dioxide is a common byproduct of metabolism

14. Environmental Factors Affect Organism Distribution
Biological environment
competition
may be interspecific or intraspecific
may result in competitive exclusion
resource partitioning allows organisms to share a resource
predator-prey relationships
balance of abundance of prey vs. predators
keystone predators
boom-or-bust cycles result from imbalances

15. Environmental Factors Affect Organism Distribution: symbiosis: living together
mutualism – both organisms benefit from the relationship
parasitism – the parasite lives off the host; the parasite benefits while the host is harmed
commensalism – one organism benefits, whereas the other is nether harmed nor benefited

16. Populations and Communities
Population – a group of the same species that occupies a specified area
Community – composed of populations of different species that occupy one habitat at the same time

17. Populations and Communities
Population growth
there are many ways in which a population can increase in size
e.g., recruitment
exponential growth
logistic growth
carrying capacity

19. Populations and Communities
Distribution of marine communities
pelagic division
neritic zone and oceanic zone
plankton and nekton
benthic division
shelf zone, bathyal zone, abyssal zone, and hadal zone
epifauna and infauna
photic zone, disphotic zone, and aphotic zone

21. Ecosystems: Basic Units of the Biosphere
Examples of ecosystems
estuaries
salt marshes
mangrove swamps
rocky shores
sandy beaches
kelp forests
coral reefs
open ocean

22. Ecosystems: Basic Units of the Biosphere
Energy flow through ecosystems
Producers
photosynthetic producers
chemosynthetic producers

24. Ecosystems: Basic Units of the Biosphere
Measuring primary productivity
rate at which energy-rich food molecules are being produced from inorganic matter
light-dark-bottle method
measuring carbon in organic products of photosynthesis

25. Ecosystems: Basic Units of the Biosphere
Consumers
first-order consumers
second- and third-order consumers
detrivores
decomposers
Food chains and food webs
Other energy pathways
dissolved organic matter (DOM)
detritus

28. Ecosystems: Basic Units of the Biosphere
Trophic levels
number is limited because only a fraction of the energy at one level passes to the next level
ecological efficiency
10% rule
trophic pyramids
as energy passed on decreases, so does the number of organisms that can be supported

31. Biogeochemical Cycles
Hydrologic cycle
water is lost through evaporation
returned through precipitation and runoff

33. Biogeochemical Cycles
Carbon cycle
carbon released from organisms through respiration and decomposition
recycled by photosynthetic producers
carbon is used in shells, corals and skeletons as part of calcium carbonate

35. Biogeochemical Cycles
Nitrogen cycle
producers use nitrogen to synthesize proteins (amino acids)
bacteria recycle nitrogen from wastes and decomposing, dead organisms
fixation of atmospheric nitrogen by microorganisms