1. Ecology

2. Levels of Organization Organism- an individual living thing
Ecology- the study of interactions ++among living things, and between living things and their surroundings
Levels of Organization
Organism- an individual living thing
EX: alligator
Population- a group of the same species that lives in one area
EX: all the alligators that living in a swamp
Community- a group of different species that live together in one area
EX: groups of alligators, turtles, birds, fish and plants that live together in the Florida Everglades
Ecosystem- all the organisms as well as the climate, soil, water, rocks and other nonliving things in a given area
EX: The grass, rocks, water, soil, turtles,
birds, alligators and plants that make up a
wetland ecosystem
Biosphere- all of Earth’s ecosystems

4. An ecosystem includes both biotic and abiotic factors.
Biotic factors- living things, such as plants, animals, fungi and bacteria
Abiotic factors- nonliving things such as moisture, temperature, wind, sunlight and soil
Can you identify the biotic and abiotic factors in the pictures below?

5. Biodiversity- the assortment or variety of living things in an ecosystem
EX: A rainforest has a high level of biodiversity because it consists of a large assortment of different species living near one another

6. Environmental Limits on Population Size
Within any ecosystem, resources such as oxygen, carbon dioxide, water, nutrients, space and sunlight are finite (limited)
Competition- the struggle for resources among organisms
Competition keeps the size of that species’ population in check
Limiting Factors- factors in the environment that limit the size of populations (biotic and abiotic)
Population sizes are limited due to predator-prey relationships
Prey- organisms that are killed for food
Predators- organisms that kill and eat other organisms
Carrying Capacity- the number of
organisms of any single species
that an ecosystem can support
Determined by the available
energy, water, oxygen, minerals, and
organism interactions

7. Habitat- all of the biotic and abiotic factors in the area where an organism lives
Ecological Niche- all of the physical, chemical and biologocial factors that a species needs to survive, stay healthy and reproduce
EX: type of food a species eats and how a species competes with others for food

8. Producers- organisms that get their energy from nonliving resources meaning they make their own food
Also called autotrophs
Provide energy for other
organisms in an ecosystem
Consumers- organisms that get their energy by eating other living or once-living resources such as plants and animals
Also called heterotrophs

9. Types of Consumers Herbivores- organisms that eat only plants
EX: desert cottontails
Carnivores- organisms that eat only animals
EX: Harris’s hawks
Omnivores- organisms that eat both plants and animals
EX: Kangaroo rats, bears
Detritivores-organisms that eat detritus or dead, organic matter.
EX: millipede
Decomposers- detritivores that break down organic matter into simple compounds
EX: fungi, bacteria
Scavengers- consumers that eat dead organisms
EX: vulture

10. Food Chain- a sequence that links species by their feeding relationships
The chain follows the connection between one producer and a single chain of consumers within an ecosystem

11. Food Web- a model that shows the complex network of feeding relationships and the flow of energy within an ecosystem

12. Trophic Levels- levels of nourishment in a food chain
EX: producer-herbivore-carnivore chain has 3 trophic levels
Carnivores are at the highest or top trophic level
Herbivores are at the second trophic level
Producers are at the first or bottom trophic level
Primary consumer- herbivores
because they are the first
consumer above the producer
trophic level
Secondary Consumer- carnivores
that eat herbivores
Tertiary Consumers- carnivores
that eat secondary consumers

14. Energy Pyramid- a diagram that compares energy used by producers, primary consumers and other trophic levels
Energy transferred up the energy pyramid. Between each trophic level, energy is lost (90%)as heat into the atmosphere. Only 10% is transferred!

15. Ecological Succession
Ecological Succession- series of changes by which one habitat changes into another
Environments change over long period of time to become habitats for many diverse species
Climatic changes, natural disasters and activities of animals can alter stable ecosystems
Changes can occur rapidly (forest fire or flood) or slowly (climatic changes or long-term drought)

16. Ecological Succession

17. Regents Review Questions for Ecology!

18. Brief Review: Ecology! Abiotic vs. Biotic Factors
Autotroph vs. Heterotroph
Food Chains and Food Webs
Energy Pyramids

19. Practice Questions
Organisms that are able to manufacture organic nutrients from substances in the abiotic environment are classified as (1) heterotrophs (3) predators (2) fungi (4) autotrophs

20. More Practice
If the population of mice is reduced by disease, which change will most likely occur in the food web?
1)The cricket population will increase.
2)The snake population will increase.
3)The grasses will decrease.
4)The deer population will decrease.

21. One More Question…
Which graph best represents the relative energy content of the levels of this pyramid? 1) 2) 3) 4)

22. Plant needs oxygen, carbon dioxide, water and minerals to survive
Plant needs oxygen, carbon dioxide, water and minerals to survive. This statement shows that autotrophs depend on
A) Symbiotic relationships
B) Abiotic Factors
C) Biotic Factors
D) Food chains

23. All plants, animals and micro-organisms living in a forest ecosystem constitute a: A) Population B) Species C) Phylum D) Community

24. Vultures, which are classified as scavengers, are an important part of an ecosystem because they
a. hunt herbivores, limiting their populations in an ecosystem
b. feed on dead animals, which aids in the recycling of environmental materials
c. cause the decay of dead organisms, which releases usable energy to herbivores and carnivores
d. are the first level in food webs and make energy available to all the other organisms in the web

25. The reason that organisms can not produce populations of unlimited size is that: a. the resources of Earth are finite b. there is no carrying capacity on Earth c. species rarely compete with one another d. interactions between organisms are unchanging

26. Two closely related species of birds live in the same tree
Two closely related species of birds live in the same tree. Species A feeds on ants and termites, while species B feeds on caterpillars. The two species coexist successfully because a. each occupies a different niche b. they interbreed c. they use different methods of reproduction d. birds compete for food

27. Which condition would cause an ecosystem to become unstable. A
Which condition would cause an ecosystem to become unstable? A. only heterotrophic organisms remain after a change in the environment b. a slight increase in the number of heterotrophic and autotrophic organisms occurs c. a variety of nonliving factors are used by the living factors d. biotic and abiotic resources interact

28. Brief Review: Human Impact
Humans have a had a NEGATIVE impact on the environment.
Issues: Deforestation, Acid Rain, Loss of Biodiversity, Pollution, Global Warming, etc.
How to Correct? Make Laws or Educate

29. Question Time
Which human activity would most likely deplete finite resources? (1) use of natural enemies to eliminate insect pests (2) development of wildlife refuges (3) governmental restriction of industrial pollution (4) uncontrolled population growth
One possible reason for the rise in the average air temperature at Earth’s surface is that (1) decomposers are being destroyed (2) deforestation has increased the levels of oxygen in the atmosphere (3) industrialization has increased the amount of carbon dioxide in the air (4) growing crops is depleting the ozone shield