1. Fundamentals of Ecology
Chapter 2
Fundamentals of Ecology
Karleskint
Turner
Small

2. Key Concepts
Ecology is the study of relationships among organisms and the interactions of organisms with their environment.
An organism’s environment consists of biotic (biological interactions) and abiotic (non-living, physical) factors.
An organism’s habitat is where it lives, and its niche is the role the organism plays in its community.

3. Key Concepts
All organisms expend energy to maintain homeostasis, i.e., internal balance relative to external changes.
Physical factors of the environment, such as sunlight, temperature, salinity, exposure, and pressure, will determine where organisms can live.
Species interactions that influence the distribution of organisms in the marine environment include competition, predation and symbiosis.

4. Key Concepts
Marine ecosystems consist of interacting communities and their physical environments.
Most populations initially grow at an exponential rate, but as they approach the carrying capacity of the environment, the growth rate levels off.
Energy in ecosystems flows from producers to and through consumers.

5. Key Concepts
The average amount of energy passed from one trophic level to the next is approximately 10%, limiting the number and biomass of organisms at different trophic levels.
With the exception of energy, everything that is required for life is recycled.

6. Study of Ecology Ecology Environment Habitat: where an organisms lives
Ecology
from the Greek word oikos meaning “home”
Environment
biotic factors
abiotic factors
Habitat: where an organisms lives
Ecosystems
composed of living organisms and their non-living environment

7. Figure 2-1 THE CORAL REEF HABITAT.
Pls note: In chapter 1, figure numbers were separated by a period and not a dash, e.g., Figure 2.1

8. Study of Ecology
The study of organisms interacting with one another and their environment. This entails:
biological (biotic) factors
environmental (abiotic) factors
the organism’s behavior
Niche: an organism’s environmental role

9. Figure 2-12 A NICHE.

10. Homeostasis and Distribution of Marine Organisms
Maintaining homeostasis
changes in external environment
internal adjustments to maintain a stable internal environment
optimal range
zones of intolerance

11. Figure 2-2 OPTIMAL RANGE.

12. Characteristics of the Physical Environment that Affect Organism Distribution
Sunlight
photosynthesis
vision
desiccation
Temperature
ectotherms
endotherms

13. Characteristics of the Physical Environment that Affect Organism Distribution
Salinity
solutes
osmosis
solutes in the body fluids of organisms
tolerance for variation ion environmental salinity
regulation of solutes in body fluids

14. Figure 2-4 OSMOSIS.

15. Characteristics of the Physical Environment that Affect Organism Distribution
Pressure
760 mm Hg or 1 atmosphere at sea level
increases 1 atmosphere for every 10 meters below sea level

16. Figure 2-5 PRESSURE.

17. Metabolic requirements
Characteristics of the Physical Environment that 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

18. Populations A group of the same species that occupies a specified area
A group of the same species that occupies a specified area
Geographic range
Population size

19. Distribution of Organisms in a Population
Distribution of Organisms in a Population
Population density (abundance)
Dispersion
clumped
uniform
random

20. Changes in Population Size
Can occur through:
reproduction
immigration
death
emigration
Can be affected by:
survivorship
life history
opportunistic and equilibrium species

21. Population Growth
Many ways a population can increase in size, depending on the carrying capacity of the environment
exponential/logarithmic growth
logistic growth

22. Figure 2-10 POPULATION GROWTH.

23. Population Growth Density Dependent Factors
Density Dependent Factors
have greater effect as population increases in size
Density Independent Factors
not related to population size

24. Communities
Composed of populations of different species that occupy one habitat at the same time
Niche: what an organism does in its environment
fundamental niche
realized niche

25. Communities Biological environment competition
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

26. Communities Symbiosis: living together
Symbiosis: living together
mutualism – both organisms benefit
commensalism – one organism benefits, the other is nether harmed nor benefited
parasitism – one organism benefits, the other is harmed

27. Ecosystems: Basic Units of the Biosphere
Energy flow through ecosystems
Producers = Autotrophs
(auto = self, troph = feed)
photosynthetic producers
chemosynthetic producers

28. Figure 2-16 PHOTOSYNTHESIS.

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

30. Ecosystems: Basic Units of the Biosphere
Consumers = Heterotrophs
(hetero = other, troph = feed)
first-order consumers
second- and third-order consumers
detrivores
decomposers
Food chains and food webs
Other energy pathways
dissolved organic matter (DOM)
Detritus

31. Figure 2-17 A FOOD CHAIN.

32. Figure 2-18 A FOOD WEB.

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

34. Figure 2-19 (a) ECOLOGICAL EFFICIENCY.

35. Figure 2-19 (b) ECOLOGICAL EFFICIENCY.

36. Biogeochemical Cycles
Hydrologic cycle
water is lost through evaporation
carried north and south from equator
carried west to east within each hemisphere
returned through precipitation and runoff

37. Figure 2-20 THE HYDROLOGIC CYCLE.

38. 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
fossil fuels when burned release CO2 back into atmosphere

39. Figure 2-21 THE CARBON CYCLE.

40. Biogeochemical Cycles
Nitrogen cycle
producers use nitrogen to synthesize protein forming amino acids
bacteria recycle nitrogen from wastes and decomposing, dead organisms
fixation of atmospheric nitrogen by microorganisms

41. Figure 2-22 THE NITROGEN CYCLE.

42. Biosphere Includes all of earth’s communities and ecosystems
Examples of ecosystems:
estuaries
salt marshes
mangrove swamps
rocky and sandy shores
kelp forests
coral reefs
open ocean

43. Distribution of Marine Communities
Pelagic division
neritic zone and pelagic zone
photic zone, disphotic zone, and aphotic zone
plankton and nekton
Benthic division
shelf zone, bathyal zone, abyssal zone, and hadal zone
epifauna and infauna

44. Figure 2-23 OCEAN DIVISIONS AND ZONES.