Chapter 2 Principles of Ecology 2.1 Organisms and Their Relationships Ecology The study of the relationships between living organisms and their interactions with the environment

Ecologist at Work

Levels of Organization Chapter 2 Principles of Ecology 2.1 Organisms and Their Relationships Levels of Organization Levels increase in complexity as the numbers and interactions between organisms increase. organism population biological community ecosystem biome biosphere

Organism: The most basic level of organization in an ecosystem. Chapter 2 Principles of Ecology 2.1 Organisms and Their Relationships Organism: The most basic level of organization in an ecosystem. Example: Wolf

Population : Organisms of one species that share the same geographic location Example: Wolf Pack

Biological community: a group of interacting populations that live in the same geographic area at the same time Example: Wolf Pack and Caribou

Ecosystem: a community and all of the abiotic factors that affect it Chapter 2 Principles of Ecology 2.1 Organisms and Their Relationships Ecosystem: a community and all of the abiotic factors that affect it

Abiotic Factors: Nonliving factors in an environment Organisms adapt to survive in the abiotic factors present in their natural environment Biotic Factors: Living factors in an environment

Examples of Biotic and Abiotic Factors

Biome: a large group of ecosystems that share the same climate and have similar types of communities.

A thin layer around Earth Chapter 2 Principles of Ecology 2.1 Organisms and Their Relationships The Biosphere A thin layer around Earth Extends several kilometers above the Earth’s surface Extends several kilometers below the ocean’s surface

Biosphere

The Biosphere 2.1 Organisms and Their Relationships Chapter 2 Principles of Ecology 2.1 Organisms and Their Relationships The Biosphere

Ecosystem Interactions Chapter 2 Principles of Ecology 2.1 Organisms and Their Relationships Ecosystem Interactions A habitat is an area where an organism lives. A niche is the role or position that an organism has in its environment.

Alaskan Wolf Habitat

Alaskan Wolf Niche Keeps caribou population healthy

Community Interactions Competition: when more than one organism uses resources at the same time Examples:

Predation: the act of one organism consuming another organism for food Predators: hunters Prey: the hunted

Predator-Prey Relationship

Almost every species is food for another species Predators (hunters) and prey (the hunted) have (in most cases) existed together for years

Predators have evolved into efficient killing machines (talons, canines, claws) Prey have evolved very effective defenses (smell, hearing, camouflage) The predator population is closely linked to the prey population

Symbiotic Relationships Chapter 2 Principles of Ecology 2.1 Organisms and Their Relationships Symbiotic Relationships Relationship that exists when two or more species live together Mutualism Commensalism Parasitism

Mutualism Two or more organisms that live closely together and benefit from each other Example: Lichens—a relationship between algae and fungi Algae provides food for the fungi, and the fungi provides habitat for the algae

Lichen

Commensalism One organism benefits from the relationship, the other is unaffected by it Example: anemone fish and sea anemones

Ex. Barnacles and a sea scallop

Parasitism One organism benefits at the expense of the other Ex. Sea lamprey and fish

Section 2.2 Energy Flow in an Ecosystem

Also called primary producers Chapter 2 Principles of Ecology 2.2 Flow of Energy in an Ecosystem Energy in an Ecosystem Autotrophs Organisms that collect energy from sunlight or inorganic substances to produce food Also called primary producers A lynx is a heterotroph.

Examples of Autotrophs

Heterotrophs: organisms that gain energy from consuming other organisms Also called consumers

Types of Heterotrophs: Herbivores: eat autotrophs (plants)

Carnivores: eat other heterotrophs (animals)

Omnivores: eat autotrophs and heterotrophs (plants and animals)

Detritivores eat fragments of dead matter in an Chapter 2 Principles of Ecology 2.2 Flow of Energy in an Ecosystem ecosystem, and return nutrients to it. Detritivores eat fragments of dead matter in an Fungus

Trophic level: Each step in a food chain or food web Chapter 2 Principles of Ecology 2.2 Flow of Energy in an Ecosystem Models of Energy Flow Food chains and food webs model the energy flow through an ecosystem. Trophic level: Each step in a food chain or food web

Food chain: model that shows how energy flows through an ecosystem. Chapter 2 Principles of Ecology 2.2 Flow of Energy in an Ecosystem Food Chains Food chain: model that shows how energy flows through an ecosystem.

Notice that the arrows point in the direction of the energy flow, NOT which organism eats which! The original source of energy is the sun Sun → Corn → Pheasant → Fox

There may be more than one level of consumer in a food chain Ex. Grass → grasshopper → toad → snake → hawk Producer → primary consumer (herbivore)→ secondary consumer (carnivore) → tertiary consumer (omnivore)

Food web: model representing the many interconnected food chains Chapter 2 Principles of Ecology 2.2 Flow of Energy in an Ecosystem Food Webs Food web: model representing the many interconnected food chains

Food Web Consists of two or more interacting food chains Most food chains are part of a food web

Chapter 2 Principles of Ecology

Chapter 2 Principles of Ecology 2.2 Flow of Energy in an Ecosystem Ecological Pyramids A diagram that can show the relative amounts of energy, biomass, or numbers of organisms at each trophic level in an ecosystem

Pyramid of Energy (Energy Chain)

The size of the boxes indicate the relative amount of energy available The lower levels limit the upper levels Available energy decreases as you move up the levels

Energy never “cycles,” it dissipates into the system (used for life processes and given off as heat and used for storage) Only 10% of the energy available at one trophic level can be used by the consumers at the next level

If the first level of the energy pyramid (the producers) provide 1,000J of energy, how much is available to the second trophic level? 100J

How much energy is available for the third level? 10J The fourth? 1J

Pyramid of Biomass

Pyramid of Biomass The total amount of biological matter (tissue) in a community or population Notice it takes many producers to support one shark The lower levels limit the upper trophic levels

Pyramid of Numbers

Cycles in the Biosphere Chapter 2 Principles of Ecology 2.3 Cycling of Matter Cycles in the Biosphere Energy is transformed into usable forms to support the functions of an ecosystem. The cycling of nutrients in the biosphere involves both matter in living organisms and physical processes.

Chapter 2 Principles of Ecology

Chapter 2 Principles of Ecology

Chapter 2 Principles of Ecology