Ecology, the Biosphere and Energy Flow- Chapter 3

What is Ecology? The study of the interactions of organisms and their environment.

Why Study ecology To understand the changes that occur as a result of these interactions.

Interactions and Interdependence The biosphere contains the combined portions of the planet in which all life exists, including land, water, and air.

There are webs of interdependence among the organisms and their environments

Levels of Organization Biosphere Biome Ecosystems Communities Populations Species Individual organism

Ecological Methods Ecologists use a wide range of tools and techniques to study the living world, but they all include Observing Experimenting Modeling

Why is Energy flow important? Every ecosystem needs a constant input of energy. The flow of energy in an ecosystem determines the system’s ability to sustain life.

What are sources of energy? Sunlight is the main source of energy for life on Earth. Only 3% of the sunlight is used by living things. Some organisms rely on the energy stored in inorganic chemical compounds Inorganic means not carbon based.

What happens to energy from the sun? Solar energy is captured in a process called photosynthesis. Light energy is use to power chemical reactions. CO2 + H2O Carbohydrates

Life without Light In remote places Volcanic vents, ocean floor, Yellowstone hot springs. Chemosynthetic bacteria produce food by using chemical energy

Who are producers? Only plants, some algae and certain bacteria can capture energy from sunlight or chemicals, and then use energy to produce food. These organisms are called autotrophs or producers.

Who are consumers? Many organisms cannot capture energy from the sun. They must eat or consume another organisms They are called heterotrophs or consumers.

Types of Consumers

What are Feeding Relationships? Energy flows in an ecosystem in one direction. Energy starts with the sun The producer is eaten by an herbivore, which is eaten by an omnivore, which is eaten by a carnivore This is a food chain.

What is a food web? In most ecosystems the food chains are interconnected producing a complex web of feeding relationships.

What is a trophic level Each step in a food chain or food web is a trophic level. Producers make up the 1st level Consumers make up the 2nd , 3rd or higher levels. Each consumer is dependent upon the trophic level below it.

What are ecological pyramids? Ecological pyramids are diagrams to represent the amount of matter or energy contained within each trophic level in a food web. Three types of pyramids. Biomass Energy Numbers.

Energy Pyramid Only 10% of energy is passed to the next level Energy is used up as heat and in life processes. The more levels that exist between producer and top consumer the less energy that remains of the original amount.

Biomass Pyramid Represents the amount of living matter at each trophic level. Usually expressed in grams of organic matter.

Pyramid of numbers. Shows the relative numbers of individuals at each trophic level.