1. Biology Chapter 14: Interactions in Ecosystems

2. Section One: Habitat and Niche
Habitat: all the abiotic and biotic factors in the area where an organism lives
Ecological Niche: all the physical, chemical, and biological factors that a species needs to survive, stay healthy, and reproduce.
Includes food, abiotic conditions, and behavior
Also known as the role a species plays in the community (job)

3. Section One: Habitat and Niche

4. Section One: Habitat and Niche
Competitive Exclusion: when two species compete for the same resources, one species will be better suited to the niche
Happens when different species share the same habitat

5. Section One: Habitat and Niche
Niche Partitioning
Dividing the niche based on the needs of each organism
Ecological Equivalents: species that occupy similar niches but live in different geographical regions.

6. Section Two: Community Interactions
Competition: occurs when two organisms fight for the same limited resources
Predation: one organism captures and feeds upon another organism

7. Section Two: Community Interactions
Symbiosis: a close ecological relationship between two or more organisms of different species that live in direct contact with one another
Mutualism
Commensalism
Parasitism

8. Section Two: Community Interactions
Mutualism: interspecies interaction in which both organisms benefit from each other
Both organism benefit
Ex: Bees and Flowers

9. Section Two: Community Interactions
Commensalism: a relationship between two organisms in which one receives an ecological benefit and the other is not benefitted or harmed
Ex: Shark and Remora

10. Section Two: Community Interactions
Parasitism: one organism benefits and the other is harmed
Different from predation because the host is not killed
Ex: Humans and Mosquitoes

11. Section Three: Population Density and Distribution
Population Density: a measurement of the number of individuals living in a defined space

12. Section Three: Population Density and Distribution
Population Dispersion: the way in which individuals of a population are spread in an area or a volume
Clumped
Uniform
Random

13. Section Three: Population Density and Distribution
Survivorship Curve: a generalized diagram showing the number of surviving members over time from a measured set of births

14. Section Three: Population Density and Distribution
Types of Survivorship Curves
Type I: low level of infant deaths and a population that will generally survive till old age
Type II: survivorship is roughly equal at all stages
Type III: high birth rate and high infant mortality rate

15. Section Four: Population Growth Patterns
What effects population size?
Immigration: movement of individuals into a population
Births
Emigration: movement of individuals out of a population
Deaths

16. Section Four: Population Growth Patterns
Based on available resources
Exponential growth: when population size increases dramatically over time
Logistic growth: populations begin to grow slowly, then go through exponential growth, then slow down and level off
Creates an s-shaped curve
Occurs because of carrying capacity
Carrying capacity: the max number of individuals of a particular species that the environment can support

17. Section Four: Population Growth Patterns

18. Section Four: Population Growth Patterns
Population crash: a dramatic decline in the size of the population over a short period of time
Occurs when the carrying capacity suddenly drops

19. Section Four: Population Growth Patterns
Limiting Factors: a factor the limits population size
Density Dependent: factors affected by the number of individuals in a given area
Ex: competition, predation, parasitism, disease
Density Independent: factors of the environment that limit population growth no matter how large or small it is
Ex: unusual weather, natural disasters, human activities

20. Section Five: Ecological Succession
Succession: the sequence of biotic changes that regenerate a damaged community or create a community in a previously uninhabited area
Occurs after a disturbance in the ecosystem
Two Types:
Primary Succession
Secondary Succession

21. Section Five: Ecological Succession
Primary Succession: the development of a new ecosystem where there was none before
Ex: Volcanic eruptions caused the formation of the Hawaiian Islands
Pioneer Species: the first organisms to live in a previously uninhabited area
Secondary Succession: the reestablishment of a damaged ecosystem where the soil was left intact
Ex: Forests growing back after wild fires

22. Section Five: Ecological Succession

23. Section Five: Ecological Succession