1. What is Ecology?

2. What is Ecology?
* Ecology is the study of interactions among organisms and between organisms and their environment.

3. Levels of Organization
Biosphere – contains the combined portions of the planet in which all of life exists, including land, water, and air/atmosphere. It is our planet as a whole and where ecology takes place.
Biome – a group of ecosystems that have the same climate and similar dominant communities.
Ecosystem – a collection of organisms that live in a particular place along with their non-living, or abiotic, environment.
Communities – assemblages of different populations living together in a defined area.
Populations – groups of individuals that belong to the same species and live in the same area.
Organism – an individual living thing.
Example:
Whole Planet ↓
Temperate Forest
Pond, plants, animals, water, O2, rocks
Pond, frogs, fish, plants, algae
All bullfrogs in pond
Bullfrog
Biotic Factor = living organisms influencing the environment
Abiotic Factor = non-living influences on environment

4. Ecological Levels of Organization

5. A Hierarchy of Interactions
Ecology can be divided into four increasingly comprehensive levels:
organismal ecology,
population ecology,
community ecology, and
ecosystem ecology.

6. (a) Organismal ecology
(b) Population ecology
(c) Community ecology
(d) Ecosystem ecology

7. A Hierarchy of Interactions
Organismal ecology is concerned with evolutionary adaptations that enable individual organisms to meet the challenges posed by their abiotic environments.

8. A Hierarchy of Interactions
Population ecology
addresses populations, groups of individuals of the same species living in a particular geographic area and
concentrates mainly on factors that affect
population density and
growth.

9. A Hierarchy of Interactions
Community ecology
is concerned with communities, all the organisms that inhabit a particular area and
focuses on how interactions between species affect a community’s
structure and
organization.

10. A Hierarchy of Interactions
Ecosystem ecology
is concerned with ecosystems, all the abiotic factors in addition to the community of species in a certain area and
focuses on energy flow and the cycling of chemicals among the various abiotic and biotic factors.

11. Feeding Relationships
Trophic structure is the feeding relationships among the various species in a community.
A community’s trophic structure determines the passage of energy and nutrients from plants and other photosynthetic organisms
to herbivores
and then to predators.

12. Feeding Relationships
Autotrophs – Producers – produce their own food using sun or chemicals
Plants and algae - by photosynthesis (sun’s energy)
Some bacteria – by chemosynthesis (chemical energy)
Heterotrophs – Consumers – rely on autotrophs for food
Herbivore – eat autotrophs directly (primary consumers)
Secondary consumers and up:
Carnivore – eat herbivores
Omnivore – eat both autotrophs and heterotrophs
Scavengers – feed on carcasses
Detritivores – eat decaying plant and animal material
Decomposers – break down organic material and release nutrients

13. A terrestrial food chain An aquatic food chain
Quaternary consumers
Carnivore
Carnivore
Tertiary consumers
Carnivore
Carnivore
Carnivore
Secondary consumers
Carnivore
Herbivore
Primary consumers
Zooplankton
Plant
Phytoplankton
Producers
A terrestrial food chain
An aquatic food chain

14. Food Chains
Food Chains – show the sequence of food transfer between trophic levels
algae → zooplankton → small fish → squid → shark
(notice direction of the arrowheads!!!)
This food chain idea works for simple food chains but....

15. Food Webs
…Food webs are able to show the complexity of more complicated ecosystems
Food webs link all food chains in a community together

16. Quaternary,
tertiary,
and secondary consumers
Tertiary and
secondary consumers
Secondary and
primary
consumers
Primary
consumers
Producers
(plants)

17. A Marsh Food Web

18. Biological Magnification
Organisms can’t metabolize many of the toxins produced by industrial wastes or pesticides
Toxins become concentrated as they pass through a food chain in a process called biological magnification.

19. Biological Magnification
Magnification of
DDT Concentration
Fish-Eating Birds
10,000,000
Large
Fish
1,000,000
100,000
Small Fish
10,000
Zooplankton
1000
Producers
Water 1

20. Energy Flow
**** Sunlight is the main energy source for life on Earth.****
*Energy flows through an ecosystem in one direction, from the sun or inorganic compounds to autotrophs (producers) and then to various heterotrophs (consumers). Energy is NOT reused.
Chemical cycling is the use and reuse of chemical elements such as carbon and nitrogen within the ecosystem.

21. C m a c i e h l y n g
Energy flow
Light
energy
Chemical
energy
Heat
energy
Bacteria,
protists,
and fungi
Chemical
elements

22. Primary Production and the Energy Budgets of Ecosystems
The amount, or mass, of living organic material in an ecosystem is the biomass.
The rate at which an ecosystem’s producers convert solar energy to the chemical energy stored in biomass
is primary production and
yields about 165 billion tons of biomass per year.
Different ecosystems vary considerably in their primary production.

23. Average primary production (g/m2/yr)
Open ocean
Estuary
Algal beds and coral reefs
Desert and semidesert scrub
Tundra
Temperate grassland
Cultivated land
Northern coniferous forest (taiga)
Savanna
Temperate broadleaf forest
Tropical rain forest
500
1,000
1,500
2,000
2,500
Average primary production (g/m2/yr)

24. Ecological Pyramids
****Pyramid of production (aka energy pyramid) – only roughly 10% of energy can be transferred to next trophic level because organisms use energy for respiration (breathing), movement, and reproducing. More levels between a producer and a top-level consumer means less energy remains from original amount = limited food chain length supported and more room needed for top level consumers****

25. Tertiary
consumers
10 kcal
Secondary
consumers
100 kcal
Primary
consumers
1,000 kcal
Producers
10,000 kcal
1,000,000 kcal of sunlight

26. Ecological Pyramids
Biomass Pyramid – shows amount of potential food for each trophic level (grams per unit area)
Pyramid of Numbers – shows number of individuals at each trophic level.

27. Ecological Pyramids 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.