Friday (February 18, 2011)

Today’s Agenda:

(1) Journal Question: What is a biome?

*(2) Lecture III: Ecosystems & Responses to a Changing Environment (slide 33)

(3) Begin working on Biome Project

a. Select a biome

b. Follow the instructions in your unit packet

(4) Homework: Each group member should do some research on their biome for Wednesday

-Read Chapter 22 (pp. 414 – 435)

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Lecture III: Ecosystems & Responses to a Changing Environment

By Dr. Rick Woodward

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Food Chains

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Species

A. The first step in investigating a biotic community may be simply to catalogue all the species present.

(You will be doing this for your group biome project today)

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Recall: Taxonomy

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SpeciesB. Species are the different kinds

of plants, animals, and microbes in the community.

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SpeciesC. The biological definition of a

species is the entirety of a population that can interbreed to produce fertile offspring, whereas members of different species generally do not interbreed.

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SpeciationA. Two species arise from one.

(1). Allopatric Speciation that occurs when 2 or more populations

of a species are geographically isolated from one another

The allele frequencies in these populations change Members become so different that that can no no

longer interbreed

(2). Sympatric Populations evolve with overlapping ranges Behavioral barrier or hybridization or polyploidy

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Speciation

Adapted to heatthrough lightweightfur and long ears, legs, and nose, whichgive off more heat.

Adapted to coldthrough heavierfur, short ears,short legs, shortnose. White furmatches snowfor camouflage.

Gray Fox

Arctic Fox

Different environmentalconditions lead to differentselective pressures and evolutioninto two different species.

Spreadsnorthwardandsouthwardandseparates

Southernpopulation

Northernpopulation

Early foxpopulation

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Populations A. Each species in a biotic

community is represented by a certain population; that is, by a certain number of individuals that make up the interbreeding, reproductive group.

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The Ecosystem ConceptA. Ecosystems join together the

biotic community (fish) and the abiotic conditions (salt water) that it lives in.

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The Ecosystem ConceptC. Examples of ecosystems:

1. Polar2. Tundra3. Coniferous Forest4. Deciduous Forest5. Grassland6. Tropical Rain Forest7. Temperate Rain Forest 8. Ocean (Marine); Coral Reefs9. Freshwater Biome (Lakes, Ponds, Rivers, Streams)

(Biome Project Presentations)(1) Terrestrial Biomes –on land.(2) Aquatic Biomes –water.

-You select one of the above for your project. (pp. 767-776)

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EcologyB. The study of ecosystems and

the interactions that occur interactions that occur among organisms and their among organisms and their environmentenvironment belongs to the science of ecology.

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An EcotoneA. Ecosystems are not

isolated from one another.

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An EcotoneB. One ecosystem blends into the

next through a transitional region called an ecotone.

C. An ecotone contains many species common to both systems.

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Ecosystem Boundaries: Ecotones

Land zone Transition zone Aquatic zone

Numberof species

Species in land zoneSpecies in aquatic zone

Species in transition zone only

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The BiosphereA. All the species on Earth, along

with all their environments, make up one vast ecosystem, often called the biosphere.

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Overlapping of the Spheres

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Ecosystem Organization Organisms

Made of cells Eukaryotic vs Prokaryotic

Species Groups of organisms that resemble one

another in appearance, behavior, and genetic make up

Sexual vs Asexual reproduction Production of viable offspring in nature 1.5 million named; 10-14 million likely

Populations Genetic diversity

Communities Ecosystems Biosphere

Fig. 4.2, p. 66

BiosphereBiosphere

Ecosystems

Communities

Populations

Organisms

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Sustaining Life on Earth… One way flow of

high quality energy The cycling of

matter (the earth is a closed system)

Gravity Causes

downward movement of matter

Biosphere

Carboncycle

Phosphoruscycle

Nitrogencycle

Watercycle

Oxygencycle

Heat in the environment

Heat Heat Heat

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CommunityCommunity

Association of different Association of different populations of organisms that populations of organisms that live and interact together in the live and interact together in the same place at the same time.same place at the same time.

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Responses to a Changing Environment

A. Organisms are able to survive within a wide range of environmental conditions.

(1) Temperature Conditions

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Responses to a Changing EnvironmentB. Tolerance Curve

(1) A graph or performance versus values of an environmental variable, such as temperature, is called a tolerance curve.

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Acclimation

A. Some organisms can adjust their tolerance to abiotic factors through a process of acclimation.

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Acclimation B. Spending a few weeks at a high

elevation, you will acclimate to reduced oxygen levels, or “thin air.” –over time the number of red blood cells in your body will increase.

(i.e. training for a marathon)

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Control of Internal Conditions

A. Ways an organism deals with changes to its environment:

(1) Conformers

(2) Regulators

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ConformersA. Conformers are organisms

that do not regulate their internal conditions; they change as their external environment changes.

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Conformers (1) Example: The body

temperature of desert lizards rises and falls with the temperature of the lizard’s environment.

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Regulators

A. Regulators are organisms that use energy to control some of their internal conditions.

(1) Regulators can keep an internal condition within the optimal range over a wide variety on environmental conditions.

-Example: Humans –Our body temperature remains constant throughout the day.

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Escape from Unsuitable Conditions

1. Dormancy

2. Migration

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Dormancy

A. Entering into a state of reduced activity is called dormancy.

(1) During the winter many reptiles and amphibians survive by hiding underground and becoming dormant until spring.

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MigrationA. Moving to a more favorable habitat with

better climate conditions is referred to as migration.(1) A familiar example of migration is the seasonal movements of birds, which spend spring and summer in cooler climates and migrate to warmer climates in the fall.

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Stop Here! Group Project Today-Work in groups of four-Select a biome-Draw pictures to describe your selected

biome1. List and draw 4-8 animals. 2. List and draw 4-8 plants.3. List climate conditions and the location of

your specific biome. -Present your poster to the class.a. Take notes in your composition book on

your classmates biomes. (You will be tested on your classmates

projects)