1. Unit 1: Ecology

2. The flow of energy through an ecosystem is one of the most important factors that determines the system’s capacity to sustain life.

3. Adenosine Triphosphate (ATP)
Adenine
Ribose
3 phosphate groups – the bonds between the phosphates are where the energy is stored – bonds must be broken to release the energy

4. Reminder: ATP/ADP Cycle

5. Interactions and Interdependence
Ecology
The study of interactions and relationships between organisms and their environment.

6. Interactions and Interdependence
What non-living things in their environment do organisms interact with?
Sunlight, air, water, soil, rocks
In what ways are these nonliving things essential to organisms?
Photosynthesis, Oxygen in air, bacteria live in soil, mosses on rocks, etc.

7. Biosphere
Contains the combined portions of the planet in which all of life exists, including land, water, and air (atmosphere)

8. Levels of Organization

9. Producers
Sunlight is the main energy source for life on Earth.

10. Producers
Producers are also known as autotrophs – they make their own food
Two types:
Photo-autotrophs: use sunlight in process of photosynthesis
Chemo-autotrophs: use inorganic chemicals

11. Producers -- Energy from the Sun
Photosynthesis
Using light energy to power chemical reactions to turn Carbon Dioxide (CO2) and water into Oxygen(O2) and sugars.
6CO2 + 6H2O O2 + C6H12O6
Light energy

12. Producers -- Energy from the Sun
On land, plants are the main autotrophs.
In freshwater ecosystems, algae are the main autotrophs

13. Cellular Respiration
Cellular respiration: Both autotrophs & heterotrophs perform this to release energy from food to do cellular work.
6O2 + C6H12O6 --> 6CO2 + 6H2O

14. Biochemical pathways

15. Consumers Heterotrophs
Consumers that rely on other organisms for their energy and food supply.
Indirect use of sun’s energy

16. Consumers -- Heterotrophs
Herbivores — eat plants (rabbit)
Carnivores — eat other animals
Omnivores — eat both plants and animals
Detritivores — feed on plant and animal remains called detritus.
Decomposers — break down organic matter (bacteria and fungi).

17. Feeding Relationships
Energy flows through an ecosystem in one direction:
Sunlight Producers  Consumers

18. Energy Transformations
Only 10% of the energy at each trophic level is passed on to the next:
Primary – 1st
Secondary – 2nd
Tertiary – 3rd
Quaternary – 4th
The other 90% is lost as heat when consumers burn food during cellular respiration (this is good because it helps us to maintain our body temperature!)

19. Trophic Levels

20. Food Chain
A series of steps in which organisms transfer energy by eating and being eaten; travels in one direction.
Always begins with producers who store energy in the chemical bonds of the foods they make.
Stored energy is passed on to consumers when they eat producers or other consumers.

23. Feeding Relationships
Food Web
A network of feeding relationships in an ecosystem

25. Aquatic Food Web

26. Ecological Pyramids
A diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain.
Energy Pyramid
Biomass Pyramid
Pyramid of Numbers

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.

28. Recycling in the Biosphere
Matter and energy move differently through the ecosystem.
Energy flows one way – some is lost as heat, only 10% of energy is used directly by organisms at each trophic level
Matter is RECYCLED through the ecosystem
Law of Conservation of Matter
Matter can be transformed

29. Ecosystems, Communities, & Population Growth

30. Factors in an Ecosystem
Biotic factors: living organisms with which an organism might interact.
Ex: insects, plants, etc.
Abiotic Factors: physical or nonliving factors with which an organism might interact.
Ex: sunlight, wind, soil, etc.

31. List the Biotic Factors in the picture

32. List the Abiotic factors in the picture

33. Community Interactions
Competition occurs when organisms attempt to use an ecological resource in the same place and at the same time.
Resource = any necessity of life
Examples: water, nutrients, light, food, space

34. Community Interactions
Predation occurs when one organism captures & feeds on another organism
Ex: lions hunt deer

35. Community Interactions
Symbiosis: 3 main types
Mutualism = both organisms benefit from the relationship
Commensalism = one organism benefits while the other organism is neither helped nor harmed
Parasitism = one organism benefits at the expense of the other organism

36. Mutualism
Butterflies and flowers

37. Commensalism
Barnacles on a Whale

38. Parasitism
HEARTWORMS

40. Ecological Succession
Predictable changes that occur in a community over time
Primary succession: occurs on surfaces where no soil exists
Examples: after a volcanic explosion where the land is covered with lava or ashes or on bare rock exposed by glacier melt
Pioneer species: first species to populate the area (often lichens)

41. Primary Succession

42. Ecological Succession
Secondary succession: follows a disturbance that changes an existing community without removing the soil
Example: wildfires, plowing, logging industry

44. Population Growth Affected by 3 factors: # of births # of deaths
# of organisms arriving or leaving: Immigration and emigration

45. Exponential Growth
Exponential growth occurs when organisms in a population reproduce at a constant rate
Tends to happen when resources are unlimited
Example – bacteria
2 split to become 4
4 split to become 8
8 split to become 16 and so it grows on & on

46. Exponential Growth

47. Logistic Growth
Happens when resources become less available so growth will slow or stop
Notice the pattern
When does the
growth slow & when
does it level out?