1. Ecosystems
Part 1

2. An ecosystem includes all of the organisms as well as the nonliving things in a given area.
Community
Population
Organism

3. A community is a group of different species that live together in one area.
Population
Organism

4. An ecosystem includes both biotic and abiotic factors.
anything that is LIVING is considered
biotic.
Examples:
plants
animals
fungi
Bacteria
plants

5. Abiotic factors are nonliving things.
anything that is
NON-LIVING is
considered abiotic.
Examples:
moisture
temperature
wind
sunlight
Soil
moisture
sunlight

6. Carrying Capacity and Limiting Factors

7. Carrying Capacity What exactly is carrying capacity?
Carrying capacity refers to the number of individuals a certain habitat or area can support given the resources that are available

8. Carrying Capacity
All animals need basic things to survive and they must get these things from their habitat
Animals need
Food
Water
Shelter
Space

9. Carrying Capacity
No matter where you are on planet Earth, there will be some resources that are in short supply
For instance:
In a desert water is very scarce and hard to find
In a rainforest space is limited
In the mountains food might be hard to come by

10. Carrying Capacity: Home Life
Think about your home
Everyone might have their own bed, a place to put their clothes, enough food to eat and water to drink, as well as an area they can go to and relax

11. Carrying Capacity: Home Life
Now imagine that 5 people moved in
What would happen?
What would happen if 10 people moved in?
How about 30 people?

12. Carrying Capacity:Home Life
Just like in nature, your home has a carrying capacity: a certain number of individuals that can live there and still find everything they need
Once you go above that number, life becomes very difficult!

13. All Habitats Have a Carrying Capacity
All places have a certain number of individuals that can live there and still gain everything they need
Once the number of individuals pass that number, life gets harder and harder

14. Ecosystems
Limiting Factors

15. Let’s suppose….
We have two mice…:
and they produce the standard 56 “pups” (baby mice) each year.
and each of these mice goes on to have 56 babies each year….

16. Soon….. We’d be over-run with mice on the planet!!
Why doesn’t this occur?

17. Limiting Factors
A limiting factor is an abiotic or biotic factor that limits the number of individuals in a population.

18. Limiting Factors Limiting factors can include: Space Food Water
Disasters: fire, flood, drought, disease

19. SPACE Human activities play a large role
Development, damming rivers, clear cutting forests.

20. Predators: Food
As the prey population increases, the predator population increases. As the prey population decreases, then so does the predator population.

21. Example: Lynx and Hare:

22. Disaster: Drought
If a drought comes along, the water supply goes down.
The number of animals living in or near the water would decrease because there would not be enough water to support a larger number of animals.

24. Part 2: Producers and Consumers

25. Producer
Makes food by changing light energy of the sun into chemical energy, or food
Also called Autotrophs
Ex. Plants, algae, some bacteria

26. Consumers Organisms that do not make their own food
Also known as HETEROTROPHS
Ex. Rabbits, Deer, Mushrooms

28. Heterotrophs Consumers A. Herbivores – eat ONLY plants
Ex. – Cows, Elephants, Giraffes

29. Heterotrophs Consumers B. Omnivores – eat BOTH plants and animals
Ex. – Bears and Humans

30. Heterotrophs Consumers https://www.youtube.com/watch?v=O_4HozC8qww
C. Carnivores – eat ONLY other animals
Ex. – Lions, Tigers, Hawks

31. Heterotrophs Consumers
D. Scavengers/Detritivores – feed on the tissue of dead organisms (both plants and animals)
Ex. – Vultures, Crows, and Shrimp

32. Heterotrophs Consumers
E. Decomposers – absorb any dead material and break it down into simple nutrients or fertilizers
Ex. – Bacteria and Mushrooms

33. Part 3: Food Chains

34. Food Chain

35. Food Chains
The energy flow from one trophic level to the other is know as a food chain.
The SUN begins ALL food chains.
Next, are the PLANTS, AKA Primary Producers
After producers are PRIMARY CONSUMERS
Then, SECONDARY CONSUMERS
Next, the TERTIARY CONSUMERS
Some food chains will go to another level, but most don’t go beyond four levels.
ALL food chains end with DECOMPOSERS.

36. Trophic Level Each step in a food chain is called a ___________.
The trophic level indicates:
the organism’s position in the sequence of energy transfers.
trophic level
Trophic Level
The first trophic level in a food chain is always made up of _________. These organisms are referred to as _________________.
producers
primary producers
The second trophic level is occupied by the __________ that feed on the _________. These organisms are referred to as _________________.
herbivores
producers
Primary consumers

37. Trophic Levels (feeding levels)
Secondary Consumers
(carnivores or omnivores)
Primary consumers
(Herbivores)
Primary Producers
(Autotrophs)

38. Predators of herbivores
____________________ belong to the third level. These organisms are referred to as:
secondary consumers.
Each consumer depends on the:
trophic level below it for energy.
Most ecosystems contain only ____________ trophic levels.
three or four

39. Food webs

40. Trophic Levels: Primary Producer, Primary Consumer, Secondary Consumer, Tertiary Consumer?
Grass
Mouse
Grasshopper
Frog
Owl
Hawk

41. Producer Primary consumer Secondary consumer tertiary consumer
Trophic Level:
Producer, primary consumer, secondary consumer, tertiary consumer
Grass
Producer
Mouse
Primary consumer
Grasshopper
Frog
Secondary consumer
Owl
tertiary consumer
Hawk

42. Part 4: Food Webs

43. Food web
Food web:
The network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem.
A food web links all the food chains in an ecosystem together.

45. In an ecosystem, the feeding relationships between organisms are much too complex to be shown in a …..
….. single food chain.
Many consumers eat:
more than one type of food.
More than one species may feed on:
the same organism.
Food Webs
There are many complex interactions between many different food chains.

46. A QUICK REMINDER…

47. What is the primary source of energy for an ecosystem?

48. What do the plants do with the glucose they produce?
About ____ of the glucose is used immediately in _________________.
Respiration is the conversion of:
glucose into molecules of ATP, the energy source for a cell.
half
cellular respiration
Some of the glucose molecules are used as raw materials (building blocks)
for the building of other _______ compounds within the cell.
Much of the glucose is…..
…..stored by the plant for future use.
organic

49. Part 5: Energy Pyramids

50. Ecological pyramid: Energy Transfer Between Trophic Levels
The amount of energy or matter in an ecosystem can be represented by an:
…..ecological pyramid.
Ecological pyramid:
A diagram that shows the amount of energy contained within each trophic level in a food chain or a food web.

51. organisms in the ________________.
Roughly ____ of the total energy _________ in one trophic level is passed to the
organisms in the ________________.
10%
consumed
next trophic level
The pyramid shape of the diagram to the right represents the low percentage of energy transfer from one trophic level to the next.

52. Ecological Pyramid

53. Why is the transfer of energy to the next trophic level so low?
Not all of the ______ possessed by the organisms at one trophic level will be _______ up to the next trophic level.
Organisms ____ much of the energy they ________ for their own ___________ such as respiration, movement, or reproduction.
energy
passed
use
consume
life processes
Many organisms at one trophic level will _________________ by the _________ at the next level.
The _______ of these “_______” will not be passed to the organisms at the _______ level.
escape being eaten
predators
energy
escapees
higher

54. The following is a hypothetical food chain:
grass ---> grasshopper ---> toad ---> black snake
The grass occupies what trophic level?
It is the producer.
The grasshopper occupies what trophic level?
The grasshopper is the primary consumer.
The toad occupies what trophic level?
Secondary consumer
The black snake occupies what trophic level?
Tertiary consumer
If the energy content of grass is approximately 5,000 calories per square meter of land surface, then the energy content of the black snakes should be approximately how many calories per square meter?
Answer: About 5 calories per square meter.

55. The low rate of energy transfer between trophic levels explains why:
food chains rarely contain more than a few trophic levels.
Organisms occupying the lower trophic levels are usually much more _________ than organisms belonging to the highest level.
There are many more grasses, shrubs, and trees than there are __________.
There are many herbivores (deer, antelope, gazelles) for each ______________.
abundant
herbivores
Higher trophic levels contain less ______, and therefore, they can support fewer _________.
energy
carnivore (lion)
individuals

56. Transfer of Energy
When a lion eats a zebra, it does not get all of the energy from the zebra (much of it is lost as heat)
Only 10% of the energy from one trophic level is transferred to the next – this is called the 10% rule

57. Ecological Pyramid
Which level has the most energy?
Which level has the most organisms?
Which level has the least organisms?
Which level has the least energy?

58. Three hundred trout are needed to support one man for a year
Three hundred trout are needed to support one man for a year. The trout, in turn, must consume 90,000 frogs, that must consume 27 million grasshoppers that live off of 1,000 tons of grass. -- G. Tyler Miller, Jr., American Chemist (1971)