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Reference Modern Biology Chapter 19 - 23

ECOLOGY

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Words to Knowecosystem trophic levelcommunity energy pyramidpopulation biodiversityhabitat food chainadaptation biome

ecology nitrificationniche biomagnificationsymbiosis bioticfood web abioticproducer consumer decomposer succession

Big Idea

Interdependence of Organisms– All organisms affect and are affected

by living and non-living components of their environment.

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Click on the picture to view a short video

Assessing Prior KnowledgeHow might a constantly changing

environment affect natural selection?

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What is Ecology?

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The study of this relationship between organisms and the living and non-living things of their environment is called Ecology.

All the organisms in an ecosystem relate to all the other living parts, as well as all the non-living parts of the ecosystem…They have a relationship…

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WHAT IS AN ENVIRONMENT?

Some examples of environments are wetlands, deserts, grasslands, forests, and large bodies of water.

An environment is the collection of all the animals and plants in a specific area of land or water. Each environment has its own characteristics such as climate, soil or water content, and plant and animal life.

Dessert EnvironmentUrban Environment

Polar Environment Salt-WaterEnvironment

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ECOLOGISTSBiologists who study ecology - that is, populations, communities, and ecosystems - are called ecologists. They gather information by conducting fieldwork – studying living things in their natural habitats. The information can be used, for example, todetermine an animal's population size, diet,territorial boundaries, and behavioral patterns. Fieldwork also includes the study of the physical factors in the environment, such as the soil, rocks, air, and water.

In addition to embarking on many research trips, ecologist Andy Dobson travels with alumni to share his expertise. While leading an alumni trip to the Peruvian Amazon, he had a close encounter with this baby tapir, an animal indigenous to the region. (photo: Peter Hudson)

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ECOLOGISTSFYI: One aspect of fieldwork is sampling a population of organisms. The technique of sampling uses a representative portion of a population to determineone particular characteristic of the entire population.

Crab Sampling

Stream Sampling Marine Life Sampling

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ECOLOGICAL MODELSFYI: Because ecosystems are complex and often difficult to study, Ecological Models are often used to help them understand the environment make predictions about how the environment might change.

Effect of Climate Change & Disease

Global Temperature Change Predicting Ozone

Change

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Why is it important to study Ecology?

Studying Ecology will help you understand how natural phenomena (not a man-made event) and human activity

can affect the balance of natural cycles and alter the living world within an

ecosystem…

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Why is it important to study Ecology?

Learning how to improve our effect on the environment is critical to our survival…

Over the past few decades, humans have altered the environment on a greater scale than ever before…

Exploding Human Population

Mass Extinction Thinning OzoneLayer

Climate Change

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Today’s Environment

Click on the Link Above to Access the “World Populations Clock” – How many people lived on earth in 1930? Today?

http://www.worldometers.info/world-population/

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Levels of OrganizationTo understand the environment better, Ecologists organize the environment into hierarchy of levels, each with unique properties.

1. Biosphere2. Biome3. Ecosystem4. Community5. Population6. Individual Organism

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Biosphere: thin layer of earth and its atmosphere in which life exists (all the places life can be found around earth).In other words, a biosphere is the sum of all the ecosystems established on Earth.

• It is about 13 miles thick• Extends from 6 miles above the earth’s

surface to deepest parts of the ocean.•Includes:• Atmosphere-air• Lithosphere-land• Hydrosphere-water

**Most organisms are found very close to the surface of land or water.

Levels of Organization

BIOSPHERE

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Biomes: Ecologists divide the biosphere into large areas called biomes.

Biomes are areas of land or water that have similar weather conditions.

Some examples of biomes are oceans, forests, grasslands, tundras, and deserts.

Biomes are made ofsimilar smaller unitscalledEcosystems

Levels of Organization

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Ecosystems: Ecosystems are all of the living organisms (biotic) interacting with their non-living (abiotic) environment in a particular place.

Every organism in an ecosystem interacts with, and needs each component (living & non-living) for its survival.

Levels of Organization

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FYI: An ocean ecosystem includes fish, mammals, plants, and algae. It also includes the materials that make up the ocean floor, rocks, salt water, the temperature, availability of sunlight and much more.

Levels of Organization

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Levels of Organization

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Levels of OrganizationFYI: The size of ecosystems varies tremendously. An ecosystem could be an entire rain forest, or it could be a puddle or a backyard garden. Even the body of an animal could be considered an ecosystem, since it is home to numerous microorganisms.

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For example, this picture shows a small, decaying tree trunk ecosystem

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This pond is an ecosystem.

This forest is an ecosystem.

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Levels of Organization

The open ocean and the rocky shore line are both ecosystems.

Different organisms live in each ecosystem.

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Levels of OrganizationAll ecosystems fall into 2 categories:

1. Terrestrial (land)- forest, desert..2. Aquatic (water)-lake, marsh,

ocean..

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Biodiversity is the variety of life. Let’s look at the species biodiversity within a local pond. 

Community: This includes all the populations of organisms of different species living in a specific geographic area at one time.In the diagram below, note how populations of gold fishes, salmons, crabs and herrings coexist

in a specfic location. A thriving community usually includes great biodiversity.

Levels of Organization

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Example:A group of the same type of sea otter that all live in the same place is called a population of sea otters.

Populations: A group of individuals of a given species that lives in a specific geographic area at a given time is called a population. Populations include individuals of the same species that can breed together.

Levels of Organization

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No population ever lives alone.

All populations interact with each other in a given community.

FYI: There are many different populations in any given community. In an ocean community, there might be many populations of fish. There may also be a population of sea otters, and a population of sea turtles all living together in the same ecosystem.

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Individuals, species, organisms: The simplest level of organization in ecology is that of the individual organism or species. Individuals do not breed with individuals from other groups or species.

Animals, unlike plants, tend to be very definite with this definition because some plants can cross-breed with other fertile plants.

Levels of Organization

Levels of Organization in an Ecosystem

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The key theme of Ecology is

interconnectedness.No organism is isolated.

To survive, an organism interacts with its

environment to maintain biological stability and to

survive.

A Key Theme in Ecology

Credit: Wikimedia Commons

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ECOLOGY OF ORGANISMS

Environmental factors that influence an

organisms ability maintain biological stability and survive include:

**BIOTIC FACTORS – living parts**ABIOTIC FACTORS – nonliving parts

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Biotic factors - The living parts of an environment.For a fish in the aquarium, the biotic factors could include other fish, snails, algae, and plants.

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Components that involve non-living things are known as abiotic.

For that same fish, the abiotic factors could include the water, air bubbles,

gravel, water acidity and salinity, temperature, wind, and the sunlight

amount.

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So, all the biotic as well as the abiotic factors influence an organism ability maintain

biological stability and survive AND

contribute to a balanced ecosystem.

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Abiotic or Biotic?

Abiotic

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Abiotic or Biotic?

Biotic

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Ecosystems, when left alone, are usually balanced. Ecosystems stay in balance because organisms respond to their environment.

Ecology of Organisms

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Organisms respond to changes in their environment:

•Immediate response/migration-leave the area•Acclimation-adjust their tolerance to abiotic factors over time.

Ecology of Organisms

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•Control Internal Conditions- • Conformers: do not regulate their internal conditions – they

change as their environment changes (“cold-blooded”, ectotherms).

• Regulators: use energy to keep control of their internal conditions-don’t change as environment changes (“warm-blooded”; endotherms)

•Dormancy/Hibernation-reduced activity during unfavorable conditions.•Adaptation-a trait that gives an organism an advantage for survival, inherited. The “adaptation” appropriate to the environment may change over time for a species – evolution.

Ecology of Organisms

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To understand an organism's relationship to its environment we must know its role in its

environment.A species “NICHE” is its role the species play

in the environment.

The niche may include:• Its “habitat” or where it lives• the range of conditions the species can

tolerate• What it eats• Needed resources• Behaviors - When it sleeps, hunts,

reproduces, etc.

Ecology of Organisms

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The habitat of a bullfrog is a pond.

The habitat of a giant anteater is open grassland.

An organism's habitat is its "address” or home.

Every organism in an ecosystem has a place to live, called a habitat.The ocean or lake is the habitat of sea turtles.

Ecology of Organisms

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For example, a spider’s NICHE includes its habitat (web) and its job of eating insects. This helps the ecosystem stay in balance by keeping the insect population down.

**Only one niche can be occupied by only one species.

**When 2 or more species overlap, the species will compete to get what they need.

Ecology of Organisms

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FYI ~

However, if the two bird species fed on different insects in the same treetops-or on the same insects but in different parts of the trees-there would be less overlap in their niches and reduced competition between them.The greatest competition usually occurs between members of the same species, because such individuals are more likely to share identical niches.

If two different species of birds ate the same species of insects from treetops in the same forest, there would be competition between them. In this case, the competition between the two bird species would be intense because of the overlap in their niches.

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GENERALISTS - species with a broad niche; tolerate a range of conditions and use a variety of resources.Example-Virginia opossum

(found across the U.S).

SPECIALISTS - species with a narrow, specified niche.Example-koala (Australia)

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Organisms can come in and disrupt niches…• Introduced species• Invasive species

Introduced Species: A species brought into an area either on purpose or accidentally, that did not originally live in that area. Disrupts relationships in ecosystems whereeach species has a well-defined niche; the new species usually has little competition.• Can become widespread.• Can cause decline or destruction of

some naturally occurring species.• Ex: Zebra mussels, “killer” bees,

Dandelions, Cane toads

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Invasive species: Species that overtakes the others around it; there are no species to slow its growth.• Major issue to ecosystems• Ex:• Purple Loosestrife- introduced in 1860s; chokes waterways and wetlands in northern states.• Kudzu-introduced to control erosion along highways…grows so fast (1 foot per day) it cover trees, houses, telephone poles.

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POPULATIONSEcologists are more interested in groups of organisms than individuals. In large part, the study of ecology is about populations and communities and the factors that influence them.Thus, an important area in Ecology is the study of population growth.

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POPULATIONS

REMEMBER: A population is a group of organisms that belong to same species and live in a place at the same time.Some factors that influence populations include:• Size – number of individuals in an given area• Density – how crowded that area is• Dispersion – how scattered are the individuals in that area

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POPULATIONSPopulation Size - number of individuals that make up a population• Population size changes over time.• If the birth rate is higher than death

rate = population increases.

• If the death rate is higher than birth rate = population decreases.• If more individuals move into the area

(immigration) than leave the area (emigration) = population decreases and visa versa.

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POPULATIONSPopulation size cannot increase forever.All populations are limited by their environment.The limiting factors of an ecosystem prevent a population from growing beyond a certain size.LIMITING FACTOR - something that preventsa population from growing beyond the carrying capacity.

Examples - resources (water, food, shelter, etc) and space.

Some factors affect the population equally no matter what size the population is.

Examples - natural disasters (fire, flood)

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LIMITING FACTORS

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POPULATIONSCARRYING CAPACITY - the maximum number of individuals of a population an ecosystem can support and maintain.Every ecosystem has different carrying capacity.

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FYI ~ Limiting Factors & Carrying CapacityLimiting factors are very closely tied to carrying capacity. Many kinds of animals can increase in numbers very quickly, and may temporarily exceed the carrying capacity of their habitat. This results in stress, starvation, disease, predationand parasites, poor reproductive success and damage to the habitat. For example, multiplying muskrats can very quickly eat all the vegetation in a marsh. With the vegetation gone, food becomes the limiting factor and the muskrats may starve or move to another area. The marsh now has a reduced carrying capacity for muskrats until the vegetation grows back again.

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Population graphs can be used to show how two populations are related to one another.

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POPULATIONSPopulation Density - how many individuals in a population are in a given area.• Example- number of trees in a square

meter of forest. 54 trees/m2

Population Dispersion - how the population is spread out.

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FYI ~ Carrying Capacity for Humans ~What is the Earth’s carrying capacity for humans? Some ecologists believe that the population is already past Earth’s carrying capacity and that serious environmental problems have already begun such as:

•Inadequate freshwater supply and other resources•Forced extinction of vast number of species (lost of habitat)•Industrialization (increases pollution)

What is clear is that the human population, like any other organism can not continue to grow.

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Polluted soil, air and water; lack of food and space; and widespread disease may ultimately limit human population size.

However, people can make wise choices because we do have an environmental responsibility …….

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