1. Concepts of Ecology
Chapters 3 and 4

2. 3–1 What Is Ecology? Objectives: Describe the study of Ecology
Explain how biotic and abiotic factors influence an ecosystem
Describe the methods used to study ecology

3. What is ecology?
Ecology is the scientific study of interactions among organisms and between organisms and their physical environment

4. Interactions and Interdependence
Interactions within the biosphere produce a web of interdependence between organisms and the environment in which they live.
The interdependence of life on Earth contributes to an ever-changing, or dynamic, biosphere.

5. Biosphere
The biosphere contains the combined portions of the planet in which all of life exists, including:
land
water
air, or atmosphere
The biosphere extends from about 8 kilometers above Earth's surface to as far as 11 kilometers below the surface of the ocean.

6. Levels of Organization
To understand relationships within the biosphere, ecologists may study these ecological levels of organization:
Organism
Population
Community
Ecosystem
Biome
Biosphere

7. Organism: Individual member of a species- group of organisms that are physically similar and can interbreed with one another to produce fertile offspring
Living things may be studied on many different levels. The largest and most complex level is the biosphere. The smallest level is the molecules that make up living things.
Bison
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8. Group of organisms of the same species living in the same area
Population
Group of organisms of the same species living in the same area
Living things may be studied on many different levels. The largest and most complex level is the biosphere. The smallest level is the molecules that make up living things.
Bison herd
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9. All populations that live together in a defined area
Community
All populations that live together in a defined area
Living things may be studied on many different levels. The largest and most complex level is the biosphere. The smallest level is the molecules that make up living things.
Hawk, snake, bison, prairie dog, grass
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10. All the populations and the physical surroundings
Ecosystem
All the populations and the physical surroundings
Living things may be studied on many different levels. The largest and most complex level is the biosphere. The smallest level is the molecules that make up living things.
Hawk, snake, bison, prairie dog, grass, stream, rocks, air
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11. Ecosystem includes the biotic (living) and abiotic (nonliving) factors

12. Biome
Group of similar ecosystems that share similar climates and dominant communities of organisms (e.g tall grasses)
Living things may be studied on many different levels. The largest and most complex level is the biosphere. The smallest level is the molecules that make up living things.
Prairie biome
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13. The part of Earth that contains all ecosystems
Biosphere
The part of Earth that contains all ecosystems
Living things may be studied on many different levels. The largest and most complex level is the biosphere. The smallest level is the molecules that make up living things.
Copyright Pearson Prentice Hall

14. Ecological Levels of Organization

15. Methods Ecologists Use
All of these approaches rely on the application of scientific methods to guide ecological inquiry

16. Ecological Models
Modeling- used to explain large-scale phenomena too large or too complex to study with observation or experiments alone
Examples:
Food webs
Biogeochemical cycle diagrams
Carbon cycle affects all levels of ecological organization up to the biosphere. A model helps make all aspects of the phenomenon observable

17. 3-2 Energy, Producers, and Consumers
Objectives:
Define primary producers
Describe how consumers obtain energy and nutrients

18. Role of Primary Producers
Energy is required for all life processes
Energy flows from the sun or inorganic compounds to autotrophs (producers).
Heterotrophs (consumers) eat producers to get energy.
Without a constant input of energy, living systems cannot function.
The primary source of energy on Earth is the sun

19. Role of Primary Producers
Autotrophs – “self feeder”
Most use sunlight to create carbohydrates via photosynthesis
Oxygen created as a byproduct
Ex: Plants, some protists (algae) and some bacteria
Some bacteria create organic compounds from inorganic chemicals in a process called chemosynthesis
Live in remote places.
Also can make carbohydrates and oxygen

20. Energy Flow: Role of Producers

21. Role of Primary Producers
Autotrophs (plants, some bacteria) are called primary producers
the first producers of energy-rich compounds that are later used by other organisms
some of their self-made energy is stored and available to other organisms that eat them
Mmm…this plant is delicious.

22. Role of Consumers Heterotroph – “different feeder”
Cannot harness energy directly from the physical environment.
Must ingest food to obtain energy
Ex: animals, fungi, some bacteria, some protists

23. Energy Flow: Role of Consumers
There are many different types of heterotrophs.
Herbivores eat plants.
Carnivores eat animals.
Omnivores eat both plants and animals.
Detritivores feed on plant and animal remains and other dead matter.
Decomposers, like bacteria and fungi, break down organic matter.
Scavengers consume carcasses of animals that have been killed by other predators

24. Ch 3-3 Energy Flow in Ecosystems
Objectives:
Trace the flow of energy through living ecosystems
Identify 3 types of ecological pyramids

25. Food Chains
Energy flows through an ecosystem in one direction from producers to consumers
A food chain is a series of steps in which organisms transfer energy by eating and being eaten
a single path of energy transfer in an ecosystem
from the sun or inorganic compounds (not usually pictured)  autotrophs (producers)  various heterotrophs (consumers).
Phytoplankton, floating algae, are primary producers in aquatic food chains

26. Energy Flow: Food Webs
A food web is the complex network of feeding relationships in an ecosystem
links all the food chains in an ecosystem together
Can provide information to determine the type of heterotroph

27. Trophic levels

28. Energy Flow: Trophic Levels
Each step in a food chain or food web is called a trophic level.
Producers make up the first trophic level.
Consumers make up the second, third, or higher trophic levels.
Each consumer depends on the trophic level below it for energy.
A single organism may occupy more than one trophic level

29. Energy Flow: Role of Decomposers

30. Ecological Pyramids
An ecological pyramid is a diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain or food web.

31. Ecological Pyramids: Energy Pyramids
Only about 10 percent of the energy available within one trophic level is transferred to organisms at the next trophic level.

32. Ecological Pyramids: Energy Pyramids
Organisms use some of the energy for their own life processes
Most is lost to the environment as heat

33. Ch 3-4 Cycles of Matter Objectives:
Describe how matter cycles among the living and nonliving parts of an ecosystem
Describe how water cycles through the biosphere
Explain why nutrients are important to living things
Describe how the availability of nutrients affects the productivity of ecosystems

34. 3-3 Cycling Matter Recycling in the Biosphere
Matter is recycled within and between ecosystems.
Matter moves through an ecosystem in biogeochemical cycles

35. Biogeochemical Cycles
4 cycles of interest:
water
carbon
nitrogen
phosphorus
Nutrients are all the chemical substances that an organism needs to sustain life.
required to build tissues and carry out essential life functions
Circulated throughout biosphere in biogeochemical cycles

36. Water Cycle
All living things need water

37. Water Cycle Biotic parts of the ecosystem gain water by
Drinking
Absorption
And lose it back to the environment through
Transpiration (plants)
Urination and exhalation of water vapor (animals)

38. Carbon Cycle

39. Nitrogen Cycle

40. Nitrogen Cycle
Nitrogen is needed for protein and nucleic acid synthesis
78% of Earth’s atmosphere is nitrogen gas (N2)
Nitrogen containing products that can be used by plants
Ammonia (NH4)
Nitrate ions (NO3-)
Heterotrophs can only get nitrogen by eating other organisms

41. Bacteria and the Nitrogen Cycle
Converting nitrogen gas into ammonia is called nitrogen fixation
Only certain species of bacteria can do this
Found living on plant roots or in soil
Other nitrifying bacteria convert ammonia into nitrates
A process called ammonification
Plants use the converted products (NH4 and NO3-) to make plant proteins
A process called assimilation
Some bacteria convert nitrates into nitrogen gas (denitrification).
Like in phosphorus and carbon cycles, bacteria act as decomposers returning nitrogen back to soil
Root nodules on a legume

42. Phosphorus Cycle

43. Phosphorus Cycle
Phosphorus is important for the formation of DNA and RNA molecules.
Plants assimilate phosphorus that is in the soil
Animals get phosphorus by eating other organisms
Phosphorus is not very common and does not enter the atmosphere, instead it is found mostly on land in rock and soil.

44. Carbon Cycle Required for photosynthesis
Released during the process of cellular respiration

45. Nutrients and Productivity
The primary productivity of an ecosystem is the rate at which organic matter (biomass) is created by producers.
One factor that controls the primary productivity of an ecosystem is the amount of available nutrients

46. Nutrients and Productivity
When a limiting nutrient, phosphorus, nitrogen, etc., is introduced it can cause bursts productivity
Ex: algal blooms
Compared to land, open oceans are nutrient poor

47. Energy and Matter in Ecosystems: The Main Idea
Energy flows in one direction
Matter is transferred and recycled between the biotic and abiotic parts of ecosystems

48. Niche
An organism’s niche includes how it survives and reproduces in its environment. This includes:
Place in food web
Environmental conditions it needs to survive
Type of food it eats
How it obtains food
Other species that use it as food
When and how it reproduces
What is the niche of a bullfrog?

49. Niche
Competitive Exclusion Principle - no two species can occupy the same niche in the same habitat at the same time
Sharing a niche results in competition in nature often results in winner and loser – losing organism fails to survive
Different species can occupy similar niches.
Resource partitioning helps organisms with similar niches avoid competition

50. Warbler Niches Cape May Warbler Feeds at the tips of branches
Bay-Breasted Warbler
Feeds in the middle
part of the tree
Cape May Warbler
Feeds at the tips of branches
near the top of the tree
Spruce tree
Yellow-Rumped Warbler
Feeds at the lower parts of the tree and bases of middle branches

51. Community Interactions
Competition- same or different species attempt to use an ecological resource in the same place at the same time

52. Community Interactions
Predation - one organism captures and feeds on another organism
Predator – the one killing and eating
Prey – the food

53. Community Interactions-Symbiosis
Symbiosis- an interaction between two species living close together
Three types:
Parasitism – one is harmed (host), one benefits (parasite)
Mutualism – both benefit
Commensalism – one is neutral, one benefits

54. Mutualism
Parasitism
Commensalism