1. Interactions in Ecosystems: Day One
Chapter 14
Interactions in Ecosystems: Day One

2. Habitat versus Niche Review! What is a habitat?
All of the biotic and abiotic factors in the area where an organism lives.
Examples: grass, trees, and watering holes!
Where it lives!

3. Habitat versus Niche Review! What is a niche?
Composed of all of the physical, chemical, and biological factors that a species needs to survive
Niche includes: type of food a species eats, tolerating certain types of abiotic conditions, and a species’ behavior.
How it lives!
Habitat is like an address in an ecosystem and a niche is like the job in an ecosystem.

4. Resource availability
Provides structure to communities
What is a community?
Different groups of species
Many species share similar habitats and use some of the same resources
Florida Everglades

5. Competitive Exclusion
Can present a problem if two species use the same resource in the same way
One species will always be better adapted to the environment.

6. Competitive Exclusion
States that when two species are competing for the same resources, one species will be better suited to the niche, and the other species will be pushed into another niche or become extinct.
Example:
In Great Britain, North American gray squirrel (better suited) introduced and pushed out the native European red squirrel.
Caused red squirrel population to decline rapidly.

7. Other outcomes from competitive exclusion
Niche partitioning:
Divide resources based on competitive advantages
Evolutionary response:
Different sizes of teeth could affect the way they eat

8. Competitive Exclusion Principle

9. Ecological equivalents
Are species that occupy similar niches but live in different geographical regions.
Examples: Mantella frog of Madagascar and poison dart frog of South America
Both have the same niche in similar habitats, but will never compete for the same resources because they live in different geographical regions.

10. Community Interactions
Competition and predation are two important ways in which organisms interact.
Competition occurs when two organisms fight for the same limited resource.

11. Competition Two types of competition: Interspecific competition:
Competition between two different species (competing for space)
Examples: cats and dogs

12. Competition Two types of competition: Intraspecific competition:
Competition between members of the same species
Examples: male birds, lions

13. Predation
Process by which one organism captures and feeds upon another organism.
Timber Rattlesnake

14. More Community Interactions
Symbiosis:
Any relationship where two species live closely together and interact.
3 types:
Mutualism
Commensalism
Parasitism

15. Relationships Between Organisms

16. Ticket Out the Door
Complete the table about factors that influence ecosystems.
When does competition occur?
What is a resource?
What is the competitive exclusion principle?
What is predation?
When predation occurs, what is the organism called that does the killing AND eating, and what is the food source called?
Type of Factor
Definition
Examples
Biotic Factors
Abiotic Factors

17. Interactions in Ecosystems: Day One Continued…
Chapter 14
Interactions in Ecosystems: Day One Continued…

18. Mutualism Both species benefit from the relationship. Example:
Ants and aphids: Ants get a sugary substance from the aphid while the aphid receives protection from predators.

19. Commensalism One organism benefits while the other is unaffected.
Example:
Barnacles on whales: Barnacles “hitch” a ride on the whale gathering food during transport; the whales receives nothing out of the relationship

20. Parasitism One organism benefits while the other is harmed. Examples:
Flea and dog: Flea gets home/food while the dog is harmed because the flea feeds on its blood!

21. Parasites Two types of parasites:
Ectoparasite: lives on the outside of an organism, attaching itself to the outside of the host
Examples: fleas, ticks, and leeches
Endoparasite: found on the inside of living organisms, feed on nutrients ingested by their host
Examples: tapeworms and hookworms

23. Symbiotic Relationships – Untamed Science

24. Ticket out the Door
Determine which ecological factors are a part of a lion’s niche and which are a part of a lion’s habitat by placing the above items in the correct column.
Items: food, hunting behavior, other lions, trees, watering hole, wildebeast, zebra, sand, temperature, grass, savanna
What are the three possible outcomes of competitive exclusion?
What are ecological equivalents?
Complete the table about main classes of symbiotic relationships.
The organism from which a parasite obtains nutritional needs is called a(an) _________________________.
Habitat
Niche
Class
Description of Relationship
mutualism
commensalism
parasitism

25. Interactions in Ecosystem: Day Two
Chapter 14
Interactions in Ecosystem: Day Two

26. Populations What is a population?
A group of the same species of organism living in the same place.

27. Characteristics of Populations
How do populations grow?
Four important characteristics of a population are:
Geographic distribution
Population density
Growth rate
Age structure

28. Geographic Distribution
May also be called it’s range
Describes the area inhabited by a population
Varies in size depending upon the type of organism

29. Geographic dispersion
Shows how individuals in a population are spaced
Allows ecologists to study population dispersion
Way in which individuals of a population are spread in an area or a volume
Three types of population dispersion:
Clumped dispersion
Uniform dispersion
Random Dispersion

30. Clumped dispersion
Individuals live close together in groups in order to facilitate mating, gain protection, or access food

31. Uniform dispersion
Individuals living at specific distances from one another
Caused by territoriality and intraspecific competition

32. Random dispersion
Individuals are spread randomly within an area or volume

33. Population Dispersion

34. Population density Number of individuals per unit area (defined space)
Varies greatly depending on the species and ecosystem
Measures the “crowdedness” of an area
Population density =
# of individuals
area (units2)

35. Population growth Affected by three factors Number of births
Number of deaths
Number individuals that enter and leave the population
Immigration – movement INTO an area
Emigration – movement OUT of an area

36. Ticket Out the Door
What are four main characteristics of a population?
What is a population’s geographic distribution?
Another term for geographic distribution is ____________________.
What is population density?
What three factors affect population size?
If more individuals are born than die in any period of time, how will the population change?
Complete the table about changes in population size.
Type of Change
Definition
Resulting Change in Size
Immigration
Emigration

37. Interactions in Ecosystem: Day Two Continued…
Chapter 14
Interactions in Ecosystem: Day Two Continued…

38. Population growth based on available resources
Growth is a function of the environment
Directly determined by the amount of resources available
Two distinct types of population growth
Exponential
Logistic

39. Exponential growth Population has abundant space and food
Occurs when the individuals in a population reproduce at a constant rate
Lack of limiting factors (causes population growth to decrease)
Shown as a J-shaped curve in a graph
Examples: bacteria!

40. More on exponential growth
When a population has unlimited resources and continues to grow to its full living potential, it is called its biotic potential.
A population that has reached biotic potential has reached its maximum reproductive capacity.
That means it has reproduced as much as it can!

41. Logistic Growth
Occurs when the population’s growth slows or stops following a period of exponential growth
Most realistic
Caused by resources becoming less available
Influenced by limiting factors
Can slow down when birthrate decreases or death rate increases
Represented as an S-shaped curve

42. Carrying Capacity Represented as K
Largest number of individuals that a given environment can support
Can change when the environment changes
Region A= very close to exponential growth
Region B= declining birthrate; inc. death rate
Region C= pop. reaches K; usually fluctuates around Carrying Capacity

43. Limiting factors Is a factor that causes population growth to decrease
Two types of limiting factors:
Density-dependent
Density-independent

44. Density-Dependent Factors
Depends on population size
Becomes limiting only when the population density reaches a certain level
Density is the number of organisms per unit area
Best seen when population is large and dense
Do not affect small, scattered populations
Examples: competition, predation, parasitism, and disease

45. Competition
Occurs if crowded organisms compete for food, water, space, sunlight, and other essentials
Can occurs between members of the same species
Can also occur between members of different species…remember no two species can occupy the same niche in the same place at the same time

46. Effect of Predation Population size often controlled by predation
Takes place in the predator-prey relationship
Best mechanism of population control

47. Parasitism and Disease
Limit growth of population
Take nourishment at the expense of their hosts often weakening them and causing disease and death

48. Density-Independent Factors
Affect all populations regardless of size
Examples: unusual weather, natural disasters, seasonal cycles, and human activities
Can see a population crash
Dramatic decline in the population size over time

49. Age Structure
Population growth depends on how many people of different ages make up a given population.
Populations with large numbers of young offspring have greater potential for rapid growth
Population Pyramids or Age-Structure Diagrams show age structure in a population.

50. Patterns of Population Growth
The scientific study of human populations is called demography
Examines the characteristics of human populations and attempts to explain how those populations will change over time
Birthrates, death rates, and the age structure of a population help predict why some countries have high growth rates while other countries grow more slowly
Talk about Thomas Malthus…pg 130.

51. Human Population Growth
It took from the beginning of mankind to around 1800 for the human population to reach 1 billion.
In the last 200 years, the human population has reached just over 6 billion.
The U.N. estimates the world’s population to be 12.5 Billion by 2050.
What effects will these numbers have on the
Earth? Other forms of life?

52. The Demographic Transition
Over the past century, population growth in the US, Japan, and much of Europe has slowed dramatically.
One hypothesis as to why these countries have slowed in their growth is the demographic transition (a dramatic change in birth and death rates).
As countries modernize, there are advances in nutrition, medicine, and sanitation.
These result in more children surviving into adulthood and more adults living to old age.
These changes lower the death rate and begin the demographic transition.

53. Population Biotic Potential

54. Births Emigration Deaths Immigration
Ticket out the Door
How will a population change if there is abundant space and food and if the population is protected from predators or disease?
When does exponential growth occur?
When does logistic growth occur?
Word Bank:
Births Emigration Deaths Immigration
When resources are abundant in a particular area, individuals may move into the population of this area. This movement of individuals into a population from a different population is called __________________.
A very cold winter has left many deer in a population hungry and sick. By the end of the winter, this population will likely decrease because of ____________________.
A deer population experiences growth when the rate of reproduction increases. This change in population size is due to ___________________.
As humans move into their territory, many members of a deer population move away and join other herds. This movement of individuals out of a population into a new population is called _______________________.

55. Interactions in Ecosystems: Day Three
Chapter 14
Interactions in Ecosystems: Day Three

56. Ecological succession
Succession means the sequence of biotic changes that regenerate a damaged community in a previously uninhabited area
Ecosystems are constantly changing in response to natural and human disturbances.
When an ecosystem changes, older organisms gradually die out and new organisms move in.

57. Ecological succession
Can result from slow changes in the physical environment
Sudden natural disasters or human activities also play a role in ecological succession
Ecological succession can be
Primary
Secondary

58. Primary succession
Establishment and development of an ecosystem in an area that was previously uninhabited
Occurs on land where no soil exists
Occurs on surfaces formed as volcanic eruptions build new islands or cover the land with lava rock or volcanic ash
Can also occur on bare rock

59. Primary succession
First, lichens that do not need soil to survive grow on rocks
Lichens are made up of fungus and algae; helps break up rocks
Next, mosses grow to hold the newly made soil
Each of these are known as a pioneer species
Meaning these are the first species to populate an area

60. Primary succession
Soil starts to form as lichens, weather, and erosion help break down rocks into smaller pieces
When lichens die they decompose, adding organic matter to the rock to make soil

61. Primary succession
Simple plants like mosses and ferns can grow in the new soil

62. Primary succession
Simple plants die, adding more nutrients to the soil
Soil layer thickens
Grasses and wildflowers begin to take over

63. Primary succession
Grasses and wildflowers will die, adding nutrients to the soil
Shrubs and trees can survive now

64. Primary succession
Insects, small birds, and mammals begin to move into the area
What was once bare rock, can now support an area of life

65. Secondary succession
Begins in a place that already has soil and was once the home of living organisms
Occurs faster and has different pioneer species than primary succession
Often see this after a natural disaster such as a forest fire or volcano

69. Climax community
A stable group of plants and animals that is the end result of the succession process
Final and stable community
Does not always mean big trees
Grasses in prairies
Cacti in deserts

70. Climax Communities
Climax Communities

71. Ecological Succession

72. Ticket Out the Door What is ecological succession?
What is primary succession?
The first species to populate an area when primary succession begins are called _________________.
When a disturbance changes a community without removing the soil, what follows?
An area that was once referred to as a climax community without removing the soil, what follows?