Chapter Introduction Lesson 1 Ecosystems and Biomes Lesson

Chapter Introduction Lesson 1 Ecosystems and Biomes Lesson 2 Populations and Communities Lesson 3 Energy and Matter Chapter Wrap-Up

What are ecosystems? • Ecology is the study of how organisms interact with each other and with their environments. • Every organism on Earth lives in an ecosystem—the living and nonliving things in one place. • Different organisms depend on different parts of an ecosystem to survive.

Abiotic Factors • Abiotic factors are the nonliving parts of an ecosystem like water, light, temperature, atmosphere, and soil. • The abiotic factors in an ecosystem help to determine which organisms can live there.

Abiotic Factors (cont. ) • Different ecosystems contain different amounts and types of nutrients, minerals, and rocks in the soil.

Most living things need oxygen to survive

Biotic Factors • Biotic factors are all of the living or once-living things in an ecosystem. • A population is made up of all the members of one species that live in an area. • Organisms in a population compete for food, shelter, and mates. • A community is all the populations that live together in the same place.

Biotic Factors (cont. ) • A biome is a large region on Earth with a specific climate, physical features, plants, and other organisms. • It includes ecosystems, populations, and communities, as well as specific biotic and abiotic factors. • All biomes are part of the biosphere—the part of Earth that supports life—and can be described as either terrestrial or aquatic.

Biotic Factors (cont. ) • Terrestrial means related to land, and aquatic means related to water. • Terrestrial biomes include forests, deserts, tundra, and grasslands. • Aquatic biomes include saltwater areas and freshwater areas. • Biomes, like communities, can affect each other.

What happens when environments change? • Changes in the environment are caused by both natural processes and human actions and can occur slowly or rapidly and can have positive or negative effects.

What happens when environments change? (cont. ) • A volcanic eruption cause sudden change in an ecosystem. • Succession is the gradual change from one community to another community in an area.

Populations and Communities • limiting factor • niche • biotic potential • symbiotic relationship • carrying capacity • habitat

The area a population lives in can be large or small.

Populations (cont. ) • Sometimes the size of a population changes because the ecosystem changes. • Population density describes the number of organisms in the population relative to the amount of space available. • If a population is very dense, organisms might have a hard time finding enough resources to survive.

The size of a population can change in different ways.

Limiting factors are factors that can limit the growth of a population.

Populations (cont. ) • Biotic potential is the potential growth of a population if it could grow in perfect conditions with no limiting factors. • Carrying capacity is the largest number of individuals that can survive in an area over a long time. • The limiting factors of an area determine the area’s carrying capacity.

Populations (cont. ) • Overpopulation is when a population’s size grows beyond the ability of the area to support it.

Communities All the populations in the same area interact as a community.

Communities (cont. ) Some populations might compete with each other for resources and space.

Symbiotic Relationships • Each population has different ways to stay alive and reproduce. • All of the populations in a community share a habitat, the physical place where a population or organism lives. • A niche is the unique ways an organism survives, obtains food and shelter, and avoids danger in its habitat.

Symbiotic Relationships (cont. ) • A symbiotic relationship is one in which two different species live together and interact closely over a long period of time. • These relationships can be beneficial to both organisms, beneficial to one and harmful to the other, or beneficial to one and neutral to the other.

Types of Symbiotic Relationships • Mutualism—two species in a community benefit from the relationship. • Parasitism—one species (the parasite) benefits while another (the host) is harmed. • Commensalism—one species benefits and the other is neither helped nor harmed.

Energy and Matter • producer • consumer • food chain • food web • energy pyramid

Energy Flow • Organisms get energy from food that they make using light or chemical energy or by eating other organisms. • When one organism eats another, the energy in the organism that is eaten is transferred to the organism that eats it and does not return to its source.

Light energy is changed to food energy by a process called photosynthesis.

Organisms and Energy (cont. ) • Chemosynthesis is when organisms use chemical energy to make food. • Organisms that cannot make their own food using the Sun must depend on organisms that can and must get energy by eating food. They are called Consumers.

Organisms and Energy (cont. ) Producers change the energy available in their environment into food energy.

Organisms and Energy (cont. ) • Consumers are classified as herbivores, omnivores, carnivores, or detritivores, based on their diet. • Herbivores are animals that eat only producers, such as plants.

Organisms and Energy (cont. ) • Omnivores, such as human beings, are animals that eat both producers and other consumers. • Carnivores, such as lions, eat only other consumers. • Detritivores, including some insects, fungi, worms, bacteria, and protists, eat dead plant or animal material.

Modeling Energy Flow A food chain models how food energy moves from the environment to several organisms.

Modeling Energy Flow (cont. ) • Each stage of a food chain has less available food energy than the last one, A food web is a model that shows several connected food chains.

Modeling Energy Flow (cont. ) • Food webs show that food energy can move through several different pathways.

Modeling Energy Pyramids • An energy pyramid shows the amount of food energy available at each level of a community. • The bottom or the base of the energy pyramid has more energy than the top layer.

This energy pyramid shows how energy flows from producers to consumers.

Matter Cycles • Matter is the physical material that makes up the world around you. • Most of the matter in your body is water, but your body also contains matter in other forms such as carbon and oxygen.

Matter Cycles (cont. ) • Like energy, matter is not created or destroyed but is transferred through the environment. • Unlike energy, matter moves in cycles.

Water Cycle

Oxygen also cycles through the environment.

Oxygen Cycle • Producers release oxygen gas and consumers take it in. • Plants release oxygen as a waste product of photosynthesis. • The oxygen enters the atmosphere, and many consumers take it in when they breathe.

Oxygen Cycle (cont. ) • When organisms exhale, they release carbon dioxide, which contains oxygen and is a by-product of cellular respiration. • Some producers take in carbon dioxide, and the cycle continues.

Carbon, a fundamental building block for all living things, also cycles through the environment.

Carbon Cycle • When producers use carbon dioxide during photosynthesis, carbon is removed from the atmosphere. • Consumers eat these producers and release carbon back into the environment as a waste product • Producers again remove the carbon from the atmosphere as they continue making food, and the cycle continues.