Tuesday 5-7-13

• Do Now: Read MSP book standard LS2

• (Life Science #2)  

Content Standard:   6-8 LS2A

An ecosystem consists of all the populations living within a specific area and the nonliving factors they interact with. One geographical area may contain many ecosystems.   

Content Standard:   6-8 LS2A

 

Students are expected to:• Explain that an ecosystem is a defined

area that contains populations of organisms and nonliving factors.

• Give examples of ecosystems (e.g., Olympic National Forest, Puget Sound, one square foot of lawn) and describe their boundaries and contents.

LS2A: Ecosystems

• A biological community of interacting organisms and their physical environment

• Or:• An ecosystem is formed by the

interactions between all living and non-living things

LS2A Ecosystems:Fundamental Characteristics

• Structure: (Living & Nonliving)• Process: (Interaction)

– Energy flow– Cycling of matter (chemicals)

• Change: Dynamic (not static)

Video: Mt St Helens 3:22

Content Standard:   6-8 LS2B

Energy flows through an ecosystem from producers (plants) to consumers to decomposers. These relationships can be shown for specific populations in a food web.   

Content Standard:   6-8 LS2B Students are expected to:• Analyze the flow of energy in a

local ecosystem, and draw a labeled food web showing the relationships among all of the ecosystem's plant and animal populations.

Modified from: General Ecology, by David T. Krome

Trophic level: All the organisms that are the same number of food-chain steps from the primary source of energy

Energy Pyramid

• Bottom–greatest energy

• Top–least energy

Source: corpuschristiisd.org/user_files/91702/Ecosystem.ppt 

Food Chains

• Producers – Consumers - Decomposers

• One ecosystem will contain many food chains

• Food chains show where energy is transferred and not who eats who.

Example of a Food Chain

© 2003 John Wiley and Sons Publishers

Food web of a hot spring

Video

Food Webs 2:00

Content Standard:   6-8 LS2C

The major source of energy for ecosystems on Earth's surface is sunlight. Producers transform the energy of sunlight into the chemical energy of food through photosynthesis. This food energy is used by plants, and all other organisms to carry on life processes. Nearly all organisms on the surface of Earth depend on this energy source.    

Content Standard:   6-8 LS2C

Students are expected to:• Explain how energy from the Sun is

transformed through photosynthesis to produce chemical energy in food.

• Explain that plants are the only organisms that make their own food. Animals cannot survive without plants because animals get food by eating plants or other animals that eat plants.

Chloroplast structureChloroplasts are the organelles in plant cells that contain the pigment CHLOROPHYLL.

OVERVIEW OF PHOTOSYNTHESIS

PLANTS TAKE INCO2 AND H2O

PLANTS MAKE GLUCOSE AND OXYGEN

SUNLIGHT PROVIDES THE ENERGY 

FOR PHOTOSYNTHESIS

Photosynthesis

water

carbon dioxide

oxygen

glucose

TAKE IN USE MAKE

PLANTS(producers)

light

chlorophyll

How does it work?

Close up on a plant cell:

Cell wall

Cell membrane

NucleusLarge vacuole

Cytoplasm

Chloroplasts (containing chlorophyll)

Video

Photosynthesis Bill Nye 2:10

Photosynthesis song 3:11

Content Standard:   6-8 LS2DEcosystems are continuously changing.

Causes of these changes include nonliving factors such as the amount of light, range of temperatures, and availability of water, as well as living factors such as the disappearance of different species through disease, predation, habitat destruction and overuse of resources or the introduction of new species.    

Content Standard:   6-8 LS2D  

Students are expected to:• Predict what may happen to an

ecosystem if nonliving factors change (e.g., the amount of light, range of temperatures, or availability of water or habitat), or if one or more populations are removed from or added to the ecosystem.

M-DCC / PCB 2340C 236/5/03

Primary Succession• Never had a

community living within it

• Example: New lava or rock from a volcano that makes a new island.

M-DCC / PCB 2340C 246/5/03

Primary Succession

M-DCC / PCB 2340C 256/5/03

The Circle of Life in Secondary Succession

Natural vs. Managed

May 18, 1980

• Where can we study ecological succession in Washington State?

How Ecosystems Change 3:19

Content Standard:   6-8 LS2E

Investigations of environmental issues should uncover factors causing the problem and relevant scientific concepts and findings that may inform an analysis of different ways to address the issue.

Content Standard:   6-8 LS2EStudents are expected to:• Investigate a local environmental issue

by defining the problem, researching possible causative factors, understanding the underlying science, and evaluating the benefits and risks of alternative solutions.

• Identify resource uses that reduce the capacity of ecosystems to support various populations (e.g., use of pesticides, construction).

LS2E Videos

Dangers of Genetic Engineering 4:03

Mardon Skipper Washington 2:00

Exit

1.What is the LT?

2.What did I learn?

3.How did I learn it the best?

4.Where can I learn more?

M-DCC / PCB 2340C 336/5/03

Two types of Ecological Succession

• Primary Succession: To life previously existed.

• Secondary Succession: Follows a disturbance in an ecosystem.

M-DCC / PCB 2340C 346/5/03

Secondary Succession• Habitat partially destroyed • Fire, Tornado, landslide,

volcano. • Soil is already in place• 5X – 10 X faster than primary

succession.

M-DCC / PCB 2340C 356/5/03

Does Ecological Succession Ever Stop?

• Any ecosystem, no matter how inherently stable and persistent, could be subject to massive external disruptive forces (like fires and storms).

• Never absolutely accurate to say that succession has stopped.