1. Intro to Ecology What is Ecology?
Ecosystems are made up of the organisms and physical environment and the interactions between the living and non-living components within them
Biotic factors: living organisms
Ex. Includes plants, animals, microorganisms, dead organisms.
Abiotic factors: non-living factors
Ex. Rocks, pH of water, amount of light, air currents, temperature

2. Some key terms to consider
Species
A group of organisms sharing common characteristics that interbreed and produce fertile offspring
Population
A group of organisms of the same species living in the same area at the same time, and which are capable of interbreeding
Limiting Factors
Factors which slow down the growth of a population as it reaches its carrying capacity
Carrying Capacity
The maximum number of species or “load” that can be sustainably supported by a given area

3. Niche Structure Niche: Fundamental Niche Realized Niche
The particular set of abiotic and biotic conditions and resources to which an organism or population responds. (The role it plays)
Fundamental Niche
The full range of conditions and resources in which a species could survive and reproduce. (potential)
Realized Niche
The actual conditions and resources in which a species exists due to biotic interactions

4. Can’t we all just get along?
Species Interaction
Can’t we all just get along?

5. Population Interactions: Competition
Intraspecific: Between members of the same species
Results: population stabilization, fittest are most successful
Interspecific: Between members of different species
Results:
Option 1: resource partitioning (sharing)
Option 2: Competitive Exclusion (Winner)
Population Interactions: Competition

6. Population Interactions
Predation: One animal eats another
Herbivory: Animal eating plant
Symbiosis: Living together
Mutualism: Relationship between 2 or more species in which all benefit and none suffer.
Commensalism: Relationship between 2 or more species in which one is helped and the other is not significantly harmed.
Parasitism: One species lives in or on another gaining its food from it.
Usually does not kill host, but can

7. Population Changes
S-Curves: Starts with exponential growth, but eventually stabilizes
Carrying Capacity: Maximum Population (can change)
Environmental Resistance: Factors that limit population size
J-Curves: Exponential followed by sudden collapse
Overshoots: When the carrying capacity is exceeded before collapse
Diebacks: Collapses are referred to as diebacks

8. (environmental resistance)
POPULATION SIZE
Growth factors
(biotic potential)
Favorable light
Favorable temperature
Favorable chemical environment
(optimal level of critical nutrients)
Abiotic
Biotic
High reproductive rate
Generalized niche
Adequate food supply
Suitable habitat
Ability to compete for resources
Ability to hide from or defend
against predators
Ability to resist diseases and parasites
Ability to migrate and live in other
habitats
Ability to adapt to environmental
change
Decrease factors
(environmental resistance)
Too much or too little light
Temperature too high or too low
Unfavorable chemical environment
(too much or too little of critical
nutrients)
Low reproductive rate
Specialized niche
Inadequate food supply
Unsuitable or destroyed habitat
Too many competitors
Insufficient ability to hide from or defend
Inability to resist diseases and parasites
Inability to migrate and live in other
Inability to adapt to environmental