Studying the Web of Life Chapter 18 Section 1 Everything Is Connected Studying the Web of Life Ecology is the study of the interactions of organisms with one another and with their environment. The Two Parts of the Environment All of the organisms that live together and interact with one another make up the biotic part of the environment. The abiotic part of the environment consists of the nonliving factors.

Studying the Web of Life, continued Chapter 18 Section 1 Everything Is Connected Studying the Web of Life, continued Organization in the Environment At first glance, the environment may seem disorganized. However, the environment can be arranged into different levels. The five levels of the environment are shown on the next slide.

Chapter 18 Section 1 Everything Is Connected

Studying the Web of Life, continued Chapter 18 Section 1 Everything Is Connected Studying the Web of Life, continued Populations Each animal is a part of a population, or a group of individuals of the same species that live together.

Studying the Web of Life, continued Chapter 18 Section 1 Everything Is Connected Studying the Web of Life, continued Communities A community consists of all of the populations of species that live and interact in an area.

Studying the Web of Life, continued Chapter 18 Section 1 Everything Is Connected Studying the Web of Life, continued

Studying the Web of Life, continued Chapter 18 Section 1 Everything Is Connected Studying the Web of Life, continued Ecosystems An ecosystem is made up of a community of organisms and the abiotic environment of the community. The Biosphere The biosphere is the part of Earth where life exists. It extends from the deepest parts of the ocean to high in the air where plant spores drift.

Chapter 18 Section 2 Living Things Need Energy The Energy Connection – Ecosystems are sustained by the continuous Flow of Energy Producers Organisms that use sunlight directly to make food are called producers. They do this by using a process called photosynthesis. Consumers Organisms that eat other organisms are called consumers. Decomposers Organisms that get energy by breaking down dead organisms are called decomposers.

The Energy Connection, continued Chapter 18 Section 2 Living Things Need Energy The Energy Connection, continued

The Energy Connection, continued Chapter 18 Section 2 Living Things Need Energy The Energy Connection, continued

The Energy Connection, continued Chapter 18 Section 2 Living Things Need Energy The Energy Connection, continued Food Chains and Food Webs A food chain is a diagram that shows how energy in food flows from one organism to another. A food web is a diagram that shows the feeding relationships between organisms in an ecosystem.

The Energy Connection, continued Chapter 18 Section 2 Living Things Need Energy The Energy Connection, continued

The Energy Connection, continued Chapter 18 Section 2 Living Things Need Energy The Energy Connection, continued Energy Pyramids An energy pyramid is a triangular diagram that shows an ecosystem’s loss of energy, which results as energy passes through the ecosystem’s food chain.

Chapter 18 Section 2 Living Things Need Energy

Chapter 18 Section 2 Living Things Need Energy Tropic Level – Each level in the transfer of energy through an ecosystem First Trophic Level – Primary Producers (autotrophs) Primary producers capture the Sun’s energy during photosynthesis, and it is converted to chemical energy in the form of simple sugars Examples: plants and phytoplankton

Chapter 18 Section 2 Living Things Need Energy Tropic Levels Second Trophic Level – Primary Consumers (heterotrophs) Primary Consumers that eat green plants are called herbivores grasshoppers, rabbits and zooplankton

Chapter 18 Section 2 Living Things Need Energy Tropic Levels Third Trophic Level (or higher) – Secondary Consumers (heterotrophs) Consumers that eat primary consumers are called carnivores Consumers that eat both producers and primary consumers are omnivores humans, wolves, frogs

Chapter 18 Energy Transfer Section 2 Living Things Need Energy Energy Transfer Carnivores or omnivores use some of the organic energy and some of the organic compounds are converted into Proteins, Carbohydrates, and Fats necessary for their body structures and functions. Much of the energy is lost as heat

Interactions with the Environment Chapter 18 Section 3 Types of Interactions Interactions with the Environment Population Density The number of individual organisms living in a defined space Carrying Capacity The largest population that an environment can support is known as the carrying capacity.

Interactions Between Organisms Chapter 18 Section 3 Types of Interactions Interactions Between Organisms Individuals and Populations Interact Populations contain individuals of a single species that interact with one another, such as a group of rabbits feeding in the same area. Communities contain interacting populations, such as a coral reef with many species of corals trying to find living space.

Chapter 18 Section 3 Types of Interactions Competition Individuals and Populations Interact When two or more individuals or populations try to use the same resource, such as food, water, shelter, space, or sunlight, it is called competition. Competition can happen within a population, or between populations.

Competition usually occurs with organisms that share the same niche Chapter 18 Section 3 Types of Interactions Competition usually occurs with organisms that share the same niche Ecological Niche – the role of an organism in its environment including Type of food it eats How it obtains food How it intersects with other organisms Two species with identical ecological niches cannot coexist in the same habitat Competition usually results in a decrease in the population of a species less adapted to compete for a particular resource.

Chapter 18 Predators and Prey Section 3 Types of Interactions Predators and Prey Predators are organisms that eat all or part of another organism. Organisms that are killed and eaten by other organisms are called prey. As the prey population increases, the predator population increases. As the predator population increases, the prey population decreases.

Chapter 18 Section 3 Types of Interactions Symbiosis Symbiosis is a relationship in which two different organisms live in close association with each other. Mutualism is a symbiotic relationship in which both organisms benefit. Bacteria in the digestive system

Chapter 18 Section 3 Types of Interactions Symbiosis Commensalism is a symbiotic relationship in which one organism benefits and the other is unaffected. Cattle egrets and cattle While cattle graze, insects are stirred up becoming prey to the egret Sea snails and hermit crabs Sea snail makes shells that other animals like hermit crabs live in for protection

Chapter 18 Symbiosis, continued Section 3 Types of Interactions Symbiosis, continued Parasitism is a symbiotic association in which one organism benefits while the other is harmed. The organism that benefits is called the parasite, while the organism that is harmed is called the host. Tapeworms, heartworms, or bacteria (internal) Fleas (external)

Two Species Interactions Chapter 18 Section 3 Types of Interactions Two Species Interactions Type of Interaction Effect on Species 1 Effect on Species 2 Coexistence & Cooperation Commensalism + Mutualism Predation + (predator) - (prey) Parasitism + (parasite) - (host) 0 means no direct effect + means positive effect - Means negative effect

Interactions with the Environment Chapter 18 Section 3 Types of Interactions Interactions with the Environment Limiting Factors A resource that is so scarce that it limits the size of a population is called a limiting factor. Competition for food, water, shelter and space Predation Parasitism Disease Weather Human activities (pollution, development) Natural disasters