1. Ecosystem Dynamics

2. Important Vocabulary Biotic Factors: living things
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Important Vocabulary
Biotic Factors: living things
Abiotic Factors: nonliving, physical things such:
Temperature, sunlight, precipitation, soil
Habitat- The area in which an organism lives.
Niche: An organism’s place / role in the ecosystem
Abiotic Factors
Biotic Factors
ECOSYSTEM

3. Five Species of Warblers and Their Niches
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Five Species of Warblers and Their Niches
No two species can share the exact same niche in a habitat.
Shaded areas show where each species feeds (one factor that defines a niche).
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4. Descriptions of a Niche Include:
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1. Its Place in the Food Web
2. Conditions Needed for Survival
a. Temperature Range it has adapted to
b. Dependability on water
3. When and how it reproduces
Top Carnivore
Ex. Corals release eggs and sperm on the same day every year.
A frog’s skin is moist so that oxygen can pass through its skin. They must also lay their eggs in water.

5. Community Interactions: Competition
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Community Interactions: Competition
Competition: occurs when organisms of the same or different species try to use the same ecological resource at the same time and place
Resource: any necessity of life
EX: water, nutrients, light, food, or living space
Uniform spacing: less competition
Clumped: more competition

6. Competition can help define the niche.
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Competition can help define the niche.
Barnacle Species A
Barnacle Species B

7. More Important Vocabulary
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More Important Vocabulary
Community: all populations living in a given area.
Populations within communities interact w/ one another in their habitat.
These relationships are important in maintaining the balance in nature.
2. Symbiosis: close relationship between 2 organisms, in which at least one of the organisms involved benefits.

8. Symbiosis: Parasitism
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Parasitism: One organism benefits, and the other is harmed (host).
Filled with blood
Ticks feed on the blood of the host in which they live. The closer together organisms live, the easier these parasites can spread through the population.

9. Symbiosis: Commensalism
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Symbiosis: Commensalism
Commensalism: One organism benefits, and the other is neither helped nor harmed.
Barnacles live and grow on the bodies of various ocean organisms like whales. However, they do not help or cause any harm to them.

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Symbiosis: Mutualism
Mutualism: Both organisms benefit from the relationship.
This bird eats insects found on the zebras’ body. The bird is high above the ground and has food, the zebra is removed of pests.
Bees receive food (nectar), while the flower’s pollen is spread for reproduction.

11. Aphids feed on sugary sap from the plant.
Aphids are herded and protected by the ants because the ants feed on sugary excretions the aphids produce.
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-Parasitism
-Mutualism

12. Predator-Prey Relationships
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Predator-Prey Relationships
Predation: interaction in which one organism captures and feeds on another organism
Predator: organism that does the killing and eating
Prey: organism that is eaten (food)
Who is the predator?
Lynx
Who is the prey?
Hare

13. Population Ecology

14. Populations and Their Growth
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Populations and Their Growth
1. Growth Rate: the change in a population’s size
2. A population’s size can increase (positive), decrease in size (negative) or remain the same size (constant)
3. Exponential growth: “J” shaped curve
4. Logistic growth: “S” shaped curve
5. Carrying capacity: largest number of individuals the environment can support.

15. Positive Population Growth
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Positive Population Growth
1. Occurs when birth rate is higher than the death rate
2. Usually occurs when conditions are ideal; will increase until something stops it
Human Population Growth Curve
German cockroach produces 80 young every 6 months. If every cockroach hatched survived for three generations, kitchens might look like this. (The Smithsonian Museum of Natural History.)

16. Negative Population Growth
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Negative Population Growth
Occurs when birth rate is lower than death rate
Ex. Overgrazing and drought left this area with out enough resources to sustain all of the wildlife.
individuals die and the population decreases.

17. Steady State -No population growth
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Steady State -No population growth
1. Occurs when birth and death rates are about equal
Steady State
Population Growth of Rabbits
Years
# of Rabbit

18. Population Boom (great increase) and Population Bust (great decrease)
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Population Boom (great increase) and Population Bust (great decrease)
Boom
Bust
The human population experienced a boom (baby boom) after world war II.

19. Limiting Factors: Limit Population Growth
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Limiting Factors: Limit Population Growth
1. Limiting factors: help stabilize population numbers when the population reaches carrying capacity for that ecosystem
a. Density independent: factors that affect all members of the population equally if population is dense or not.
Natural disasters: floods, earthquakes, wildfires, tornadoes, mudslides, pollution, habitat destruction
b. Density dependent: factors that affect crowed populations
EX: competition, predation, crowding and stress, parasitism, and disease

20. Density Independent Limiting Factors
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Density Independent Limiting Factors

21. Density Dependent Limiting Factors
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Density Dependent Limiting Factors
1. Competition for limited resources is the most important limiting factor that affects carrying capacity.
2. Predation
Most species serve as food for others
These evolved relationships are important for the health & survival of predator and prey populations.
Removes weak & unhealthy individuals
Competition
Predation

22. Density Dependent Limiting Factors
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Density Dependent Limiting Factors
3. Crowding and stress
Most animals have a built-in need for a certain amount of space & end up fighting among themselves if they become overcrowded
Increase in stress can reduce their resistance to disease, reduce mating, or cause low birth weight.
Individuals who are stressed may neglect, kill, or even eat their offspring.
As the tiger’s territory is shrinking due to habitat destruction, they fight and end up suffering from stress related problems.

23. Density Dependent Limiting Factors
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Density Dependent Limiting Factors
4. Parasitism & Disease
The more crowded the population, the easier it is for disease and parasites to spread.
Lyme disease – bacterial disease transmitted by ticks; characterized by a bulls eye shaped rash.

24. Ecological Succession
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Ecological Succession
Ecosystems are constantly changing in response to natural and human disturbances. As an ecosystem changes, older inhabitants gradually die out and new organisms move in, causing further changes in the community.
Defined as a series of predictable changes that occurs in a community over time

25. Primary Succession Occurs on surfaces where no soil exists.
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Primary Succession
Occurs on surfaces where no soil exists.
Ex: after volcanic eruption, glaciers melting

26. Slide # 25
Primary Succession
First species to populate the area is called the pioneer species.
Lichen is the most common pioneer species after a volcano.
Lichen = fungus and alga capable of growing on bare rock.
As it grows, it helps to break up the rocks.
When lichen die they add organic material to help form soil to support plants.

27. Primary Succession

28. Slide # 26
Secondary Succession
Occurs when a disturbance of some kind changes an existing community without removing the soil.
Ex: clearing land, plowing, wildfires.

29. Slide # 27
Secondary Succession
Ecologists believe that succession in a given area proceeds in predictable stages ending with a mature, stable community, referred to as a climax community.

31. Biomes: Clusters of Similar Ecosystems

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Important Vocabulary
Biome: complex terrestrial communities that cover a large area
Characterized by a:
Certain climate & soil
Certain assemblage of plants and animals
Deserts are characterized by poor soils and low precipitation.
Desert plants usually have shallow, wide spreading roots systems.

33. Relationship Between Temperature and Precipitation and Biome Location
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Relationship Between Temperature and Precipitation and Biome Location