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