1.How do these organisms interact with one another and with the nonliving parts of the environment? 2. What might happen if the zebras were removed?

Unit Overview – pages Ecology Principles of Ecology Part 1: Organisms and Their Environment

Section 2.1 Summary – pages Ecology: the study of interactions that take place between organisms and their environment. What is ecology? A key consideration of ecology is that living organisms affect other living organisms.

Section 2.1 Summary – pages Abiotic factors: the nonliving parts of an organism’s environment Examples of abiotic factors include air currents, temperature, moisture, light, and soil. The Environmental Factors: 2 main factors

Section 2.1 Summary – pages Ecology includes the study of features of the environment that are not living because these features are part of an organism’s life. The Environmental Factors: 2 main factors Abiotic factors have obvious effects on living things and often determine which species survive in a particular environment.

Section 2.1 Summary – pages The Environmental Factors: 2 main factors Biotic factors: all the living organisms that inhabit an environment Ex: bacteria, fungi, plants, animals All organisms depend on others directly or indirectly for food, shelter, reproduction or protection.

Section 2.1 Summary – pages Levels of Organization Ecologists study individual organisms, their interactions among the same species, interactions among different species, as well as the effects of abiotic factors on interacting species.

Levels of Organization Ecologists have organized the living world into levels: Organism Populations Communities Ecosystems (which depend on the landscape) Biosphere

What level is he?

What level are they?

What level is this?

Section 2.1 Summary – pages Organism An individual living thing that is made of cells, uses energy, reproduces, responds, grows, and develops.

Section 2.1 Summary – pages Populations Population: a group of organisms, all of the same species, which interbreed and live in the same area at the same time.

Section 2.1 Summary – pages Interactions within populations Members of the same population may compete with each other for food, water, mates, or other resources. Competition can occur whether resources are in short supply or not.

Section 2.1 Summary – pages Biological Communities Biological community: made up of interacting populations in a certain area at a certain time.

Section 2.1 Summary – pages Interactions within communities **A change in one population in a community may cause changes in the other populations. Some of these changes can be minor, such as when a small increase in the number of individuals of one population causes a small decrease in the size of another population.

Section 2.1 Summary – pages Ecosystem Populations of plants and animals that interact with each other in a given area and with the abiotic components of that area. Aquatic and Terrestrial

Section 2.1 Summary – pages Biotic and abiotic factors form ecosystems Freshwater ecosystems include ponds, lakes, and streams.

Section 2.1 Summary – pages Biotic and abiotic factors form ecosystems Saltwater ecosystems, also called marine ecosystems, make up approximately 70 percent of Earth’s surface.

Section 2.1 Summary – pages Organisms in Ecosystems Habitat: the place where an organism lives out its life.

Section 2.1 Summary – pages Organisms in Ecosystems Habitats can change, and even disappear. Habitats can change due to both natural and human causes.

Section 2.1 Summary – pages Niche Although several species may share a habitat, the food, shelter, and other essential resources of that habitat are often used in different ways. Niche: the role or position a species has in its environment—how it meets its specific needs for food and shelter, how and where it survives, and where it reproduces in its environment.

Section 2.1 Summary – pages Niche A species’ niche includes all its interactions with the biotic and abiotic parts of its habitat. Based on the definition of Niche; explain this statement: It is thought that two species can’t exist for long in the same community if their niches are the same.

Section 2.1 Summary – pages Symbiosis Symbiosis: the relationship in which there is a close and permanent association between organisms of different species Symbiosis means living together. 3 kinds of symbiosis are recognized: 1. Mutualism 2. Commensalism 3. Parasitism

Section 2.1 Summary – pages Mutualism Mutualism: a symbiotic relationship in which both species benefit Can you think of another example?

Section 2.1 Summary – pages Commensalism Commensalism: a symbiotic relationship in which one species benefits and the other species is neither harmed nor benefited.

Section 2.1 Summary – pages Parasitism Harmful to one species, yet beneficial to another. Parasitism: a symbiotic relationship in which a member of one species derives benefit at the expense of another species (the host)

Unit Overview – pages Ecology Principles of Ecology Part 2: Nutrition and Energy Flow

Section 2.2 Summary – pages How Organisms Obtain Energy One of the most important characteristics of a species’ niche is how it obtains energy. Ecologists trace the flow of energy through communities to discover nutritional relationships between organisms.

Section 2.2 Summary – pages Obtaining Food The ultimate source of the energy for life is the sun. Plants use the sun’s energy for the process of _________. Who/What uses the products of photosynthesis?

Section 2.2 Summary – pages Obtaining Food Autotroph: an organism that uses light energy or energy stored to make food **Primary Producers** Heterotroph: an organism that cannot make its own food and feeds on other organisms **Consumers** Feed on autotrophs, heterotrophs, and/or a combination of both

What is the reason organisms need to obtain food? What happens to that energy when an organism is consumed? Does it just “go away?”

It is important to know: Energy is a one way flow and matter is recycled Lets look…….

Section 2.2 Summary – pages Food chains: Pathways for matter and energy –In a food chain, nutrients and energy move from autotrophs to heterotrophs and, eventually, to decomposers. Food chain: a simple model illustrating how matter and energy move through an ecosystem.

Section 2.2 Summary – pages Trophic levels represent links in the chain Trophic level: a feeding step in a food chain that is represented by an organism in the passage of energy and materials.

Quaternary consumer Tertiary consumer Secondary consumer Primary consumer Producer Herbivore Carnivore/Omnivore Carnivore Producer Food Chains

Section 2.2 Summary – pages Food webs Ecologists interested in energy flow in an ecosystem may set up experiments with as many organisms in the community as they can. Food web: a model that shows all the possible feeding relationships at each trophic level in a community.

Food Webs

Section 2.2 Summary – pages Energy and trophic levels: Ecological pyramids Ecological pyramid: a model that shows the amount of energy available at each feeding level in an ecosystem. The base of the ecological pyramid represents the autotrophs, or first trophic level. Higher trophic levels are layered on top of one another.

Section 2.2 Summary – pages Energy and trophic levels: Ecological pyramids The pyramid of energy illustrates that the amount of available energy decreases at each succeeding trophic level. Pyramid of Energy Heat 0.1% Consumers 1% Consumers 10% Consumers 100% Produc ers Parasites, scavengers, and decomposers feed at each level.

Section 2.2 Summary – pages Energy and trophic levels: Ecological pyramids The total energy transfer from one trophic level to the next is only about ten percent because organisms fail to capture and eat all the food energy available at the trophic level below them. Some of the energy transferred at each trophic level enters the environment as heat, but the total amount of energy remains the same. What law is this?

Section 2.2 Summary – pages Energy and trophic levels: Ecological pyramids A pyramid of numbers shows that population sizes decrease at each higher trophic level. Pyramid of Numbers Fox (1) Birds (25 ) Grasshoppers (250) Grasses (3000)

So we have talked about energy flow, but what about matter? Lets find out

Section 2.2 Summary – pages Cycles in Nature Matter, in the form of nutrients, moves through, or is part of, all organisms at each trophic level. But matter is cycled and is not replenished like the energy from sunlight. What law is this?

The Water Cycle Water cycle: the continuous movement of water from the ocean to the atmosphere to the land and back to the ocean.

Water Cycle Water continually 1 evaporates from the Earth’s oceans, lakes, streams, and soil, and the oceans forming vapor. Water vapor 2 condenses to form water droplets which then form clouds. Droplets collide to create larger, heavier drops that then fall from the clouds as 3 precipitation.

The water cycle

The Carbon Cycle Carbon cycle: the movement of carbon from the nonliving environment into living things and back Carbon is the essential component of proteins, fats, and carbohydrates, which makes up all organisms. Carbon exists in air, water, and living organisms

The Carbon Cycle Producers convert carbon dioxide in the atmosphere into carbohydrates during photosynthesis. Consumers obtain carbon from the carbohydrates in the producers they eat. During cellular respiration, some of the carbon is released back into the atmosphere as carbon dioxide.

The Carbon Cycle

Carbon stored in the bodies of organisms as fat, oils, or other molecules, may be released into the soil or air when the organisms dies. These molecules may form deposits of coal, oil, or natural gas, which are known as fossil fuels. Fossil fuels store carbon left over from bodies of organisms that dies millions of years ago.

The Nitrogen Cycle Nitrogen cycle: the process in which nitrogen circulates among the air, soil, water, plants, and animals in an ecosystem. All organisms need nitrogen to build proteins, which are used to build new cells. Nitrogen makes up 78 percent of the gases in the atmosphere.

The Nitrogen Cycle Nitrogen must be altered, or fixed, before organisms can use it. Only a few species of bacteria can fix atmospheric nitrogen into chemical compounds that can be used by other organisms. These bacteria are known as “nitrogen- fixing” bacteria.

The Nitrogen Cycle

Decomposers and the Nitrogen Cycle Nitrogen stored within the bodies of living things is returned to the nitrogen cycle once those organisms die. After decomposers return nitrogen to the soil, bacteria transform a small amount of the nitrogen into nitrogen gas, which then returns to the atmosphere to complete the nitrogen cycle.

The Phosphorus Cycle Phosphorus is an element that is part of many molecules that make up the cells of living organisms. Phosphorus cycle: the movement of phosphorus in different chemical forms from the environment to organisms and then back to the environment.

The Phosphorus Cycle

Phosphorus may enter soil and water when rocks erode. Plants absorb phosphates in the soil through their roots. Animals get their phosphorus by eating plants or other animals that have eaten plants. Some phosphorus washes off the land and ends up in the ocean where they sink to the bottom and accumulate as sediment.