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Ecology
Mrs. Flannery
What is ECOLOGY??
• Ecology is the scientific study of the interactions between organisms and their environments.
• Biotic factors = living components of the environment.
• Abiotic factors = nonliving components of the environment
Levels of Organization
• Species (organism)
• Population
• Community
• Ecosystem
• Biome
• Biosphere
Energy Flow and Trophic Levels
• Sunlight is the main energy source on Earth!!!• Producers use the energy from sunlight to make
food, and are known as autotrophs.
PHOTOSYNTHESIS!!
Life without Light
• Some autotrophs can use other sources of chemical energy to produce food (carbohydrates).
Giant Tube Worms
• Feed on bacteria that is
capable of harnessing energy
from thermal vents deep on
the ocean floor.
• The bacteria is using
chemosynthesis to make food!
Chemosynthesis
Consumers
Heterotrophs – rely on other organisms for food.
• Herbivores
• Carnivores
• Omnivores
• Detritivores
• Decomposers
Food Chains – Trophic Levels
Feeding Relationships
Food Chains –sequence of food transfer between
trophic levels.
Food Webs –feeding
relationships in a community.
Energy Flow – Biomass ecological pyramids
Energy Flow – Biomass ecological pyramids
It takes 5000 grams of grain to feed 500 grams of cattle which will only feed 50 grams of human tissue.
Nutrient Cycles
• While ENERGY FLOWS through an ecosystem, NUTRIENTS are passed between organisms and the environment through BIOGEOCHEMICAL CYCLES.
REMEMBER that MATTER is neither
CREATED nor DESTROYED!!!!
Biogeochemical Cycles
Chemical cycles involve both BIOTIC and ABIOTIC
components.1. Producers integrate
elements from the abiotic reservoir into organic compounds
2. Consumers feed on producers integrating some of the elements into their own bodies
3. Both producers and consumers release some elements back to the environment through waste products.
4. Decomposers break down complex organic molecules.
Water Cycle
Carbon Cycle
Greenhouse Gas – CO2
Greenhouse Gas – CO2
Nitrogen Cycle
• 80% of the Earth’s atmosphere is made up of Nitrogen gas (N2).
• Organisms need nitrogen to make amino acids in order to build proteins.
• Plants cannot use N2 gas directly.
• Nitrogen Fixation = converts N2 gas into a usable form of nitrogen that plants can then use.
• Denitrification = converts nitrogen compounds back into N2 gas.
Nitrogen Cycle
Community Ecology
• Interspecific interactions- interactions between species
• Interspecific competition – competition between species.
• Ecological niche –full range of the biotic and abiotic resources an organism uses in its environment.
The Competitive Exclusion Principle
Two species cannot occupy the same niche in the same habitat at the same time.
Symbiosis
A relationship in which two species live closely together
Relationships Among Organisms in a Community
Symbiotic Relationships
• Predation – cryptic and warning coloration
– mimicry
• Parasitism
– host/parasite
• Commensalism
• Mutualism
Cryptic Coloration
Population Ecology• Focuses on changes in population size and the
factors that regulate populations over time.
– Size (# of individuals)
– Age structure
– Density (# of individuals/unit area or volume)
What do you think are some things that could cause a population to change size?
Exponential Growth Model
Logistic Growth Model
What is the
carrying capacity?
Regulation of Population Growth
• Density-dependent factors– competition
– predation
– parasitism
– disease
Regulation of Population Growth
Boom and Bust Cycles of Predators and Prey
Keystone Species
A species whose impact on the community is much larger than the population’s total
mass or abundance.
Regulation of Population Growth
• Density-independent Factors– weather
– human activity
Threats to Biodiversity
• Human Activity
• Climate Change
• Natural Disasters
• Introduction of invasive, non-native species
Non-Native Invasive Species
Non-Native Invasive Species
Non-Native Invasive Species
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