Chapter 3: The BiosphereDate Topic Page6.11.2012 Ecology! p.63

Inquiry Activity

• In groups of 2-3, you have five minutes to make a list of all of the types of organisms, including plants, humans, animals, insects etc that you have seen in a specific location.

• Rainforest• Tundra!

Inquiry Activity

• Make a diagram that shows how the organisms that you listed interact with each other.

• Who eats who/what?• Where do these organisms live?

Think About It

1. Which organisms on your list provide energy or nutrients to the others? 2. What would you expect to happen if all the plants in your diagram died? EXPLAIN your answer.3. Why is it difficult to make accurate predictions about changes in communities of organisms?

3.1: What is ecology?

• Ecology is the scientific study of interactions among organisms and between organisms and their environment

• Etymology (word Root): eco comes from the Greek oikos which means house.

The Biosphere

The biosphere contains the combined portions of the Earth in which all life exists, including land, water and air or atmosphere.

It extends 8 km above the Earth’s surface and as far as 11 km below the surface of the ocean.

Within the Biosphere are levels of organization

Definitions

Species: – A group of individuals who can reproduce and

produce fertile offspring.

Populations– Members of the same species who live together in

the same time and place.

Community vs. Population

A community is assemblage of different populations that live together in a defined area

A population is a group individuals that belong to the same species and live in the same area

5.1.1 Habitat: Definition

Habitat is the environment in which a species normally lives or

the location of a living organism.

5.1.1 Ecosystem

An ecosystem is a collection of all organisms that live in a particular place, which includes the non-living, or physical, environment

Ecosystems

A collection of all organisms that live in a particular place, which includes the nonliving, or physical, environment

What is a Biome?

• A group of ecosystems that have the same climate and similar dominant communities

Temperate ForestTundra

Whittaker’s Biome Distribution

What do Ecologists study?

• Species- Distribution and Ecophysiology• Populations- Population Growth,

Demography, Variation• Communities- Interactions among populations• Ecosystems- Productivity, Nutrient Cycles,

Global Change• Biomes- Distribution, Landscape Ecology• Conservation

KEY CONCEPT:

Regardless of the tools they use, scientists conduct modern ecology research using three basic approaches:• Observing• Experimenting• Modelling

3-2 Energy Flow

• 1. True or False: Sunlight is the main energy source for all life on Earth:

• 2. Producers are autotrophs, which means they can make their own food from sunlight or chemicals in the environment.

TRUE!

• The process that converts sunlight, water and carbon dioxide into energy is called.

Chemotrophs

4. Some autotrophs can produce food energy without light, instead they use chemicals like hydrogen sulfide. These autotrophs use a process called chemiosynthesis.

Let’s meet some…Deep Sea ChallengerCompare chemosynthesis with photosynthesisGiant Amoeba

Heterotrophs

5. Organisms that rely on other organisms for food are called heterotrophs or consumers. Complete the chart below for the different types of consumers and what they eat.

Consumers

herbivores Cows, caterpillars, deer

Carnivores MEAT! (animals)

Humans, bears, crows Plants and animals

Detritivores Animal remains, dead matter

Decomposers Bacteria, fungi

Feeding Relationships

• KEY CONCEPT: Energy flows through an ecosystem in one direction from the sun or other inorganic compounds to autotrophs (producers) and then to various heterotrophs (consumers).

Food Chains vs. Food Webs

Food Chain

Food Chains vs. Food Webs

• Look at the food web in fig. 8-3 on page 71. • Think about a forest ecosystem. Create a food

web with at least 2 organisms at each level producer through decomposer.

Challenge: 2 minutes

1. What did you eat for breakfast?2. What were the ingredients?3. Where did the energy for the ingredients

come from?.....

So what does this have to do with energy?

1. True or False: Sunlight is the main energy source for life on Earth:

2. Producers are autotrophs: an organism that synthesizes its organic molecules from simple inorganic substances.

TRUE!

which means they can make their own food from sunlight or chemicals in the environment.

• The process that converts sunlight, water and carbon dioxide into energy is called.

You must be able to define

• Autotroph• Heterotroph• Producer• Consumer• Decomposer• Detrivore

From S. Taylor, i-biology 2012

Trophic levels of organisms: Autotrophs/ Producers/ Trophic Level 1

Food energy is most commonly produced from light energy through photosynthesis

Some autotrophs can produce food energy without light, instead using chemicals like hydrogen sulfide. These autotrophs use a process called chemiosynthesis.

Trophic levels: Heterotrophs/ Consumers (and decomposers)

Organisms that rely on other organisms for food are called heterotrophs or consumers.

What do decomposers do?

Decomposers (bacteria and fungi) recycle nutrients

(organic matter and other essential elements) in an

ecosystem

Let’s meet some decomposers

• detritus 1• detritus 2

Ecological Pyramids

• An ecological pyramid is a diagram that shows the relative amounts of energy or matter (biomass) contained within each trophic level in a food chain or web.

• Ecologists recognize three different types of

ecological pyramids:1. Energy Pyramids2. Biomass Pyramids3. Pyramid of Numbers

Energy Pyramid (kJm-2)

Calculating energy efficiency

33 kJ

Only 4 kJ of the original energy available to the bullock is available to the next stage, which might be humans. The efficiency of this energy transfer is:efficiency = 4⁄100 × 100 = 4%

Biology Update!

• The “rule of 10” was based on aquatic ecosystems.

• It still generally applies… but…• Recent studies have shown that energy

efficiency can range from 0.05% to 20%.

Where does the energy go between trophic levels?

• Energy is used for metabolic processes• Not all of the energy consumed is ‘digestibel’• Some of the energy available is rejected and

not consumed (horns, feet, skin etc)

How can we optimise efficency of energy transfer?

Biomass Pyramid

• The total amount of living tissue with a given trophic level is called biomass.

• Biomass is usually expressed in terms of gram of organic matter per unit area.

• A biomass pyramid represents the amount of potential food available for each trophic level in the ecosystem.

Biomass Pyramid

Improve Efficiency

• Food production is more efficient if the food chain is short, because a higher percentage of energy is available to us.

• Most food chains have 3 – 5 trophic levels

Pyramid of Numbers

• Based on the number of organisms at each trophic level. In most forests there are less producers than there are consumers.

3-3: Cycles of Matter

• KEY CONCEPT: Unlike the one way flow of energy, matter is recycled within and between ecosystems. These are called biogeochemical cycles.

Water Cycle

Key Concept

• Every living organism needs nutrients to build tissue and carry out essential life functions. Like water, nutrients are passed between organisms and the environment through biogeochemical cycles.

Carbon Cycle

3-2-1

• What are three things you learned today?• Two things you have questions about?• One thing you want to learn more about?• Homework: none

Date Topic Page1.4. 2011 Nutrient Cycles

1:00

:30

Correcting the Reading Quizzes

• 1. All organisms require N to make ___________________ which in turn are used to build _________________.

• 2. Write the chemical formulas for the following substances (0.25/each)

• a. Nitrogen gas _______ b. Ammonia ___________ c. Nitrate ions _________ d. Nitrite ions ___________

• 3. Converting nitrogen gas into ammonia is called.

Amino acidsproteins

N2 NH3

NO3- NO2

-

Nitrogen fixation

• 4. _______________________ is a process that releases nitrogen back into the atmosphere.

• 5. Where is most of the phosphorous stored in the biosphere?

• 6. Phosphorous is essential because it is part of the

“life sustaining molecules” _________ and _________7. The ________________________________________

of an ecosystem is the rate at which organic matter is created by producers.

Denitrification

In rock and soil minerals

DNA RNA Primary productivity

• 8. When an ecosystem is limited by a single nutrient that is scarce or cycles very slowly, this substance is called a______________________________________.

• 9. Fertilizers contain __________________________, _____________________________ and potassium.

• 10. _____________________________________ occurs when there are more nutrients in aquatic ecosystems available than are consumers to eat the algae.

Limiting nutrient Nitrogen

phosphorous

Algal blooms

Using your notes and a partner….

• Draw the nitrogen cycle to the best of your abilities.

Article

• The fact that these colonies can be seen by the naked eye is what gave Trichodesmium its name - the Greek word "trichoma" for hair and "desmus" for bonded = "bonded-hair," which is how Trichodesmium colonies look to the human eye. The colonies can be yellowish-brown to deep red in color due to their primary light harvesting pigment, phycoerythrin.

Figures: (a) Streaks of Trichodesmium seen from the Nansen; (b) a Trichodesmium bloom visible from space (from AIMS Research.); (c) thick Trichodesmium “gunge” from the bongo net haul; (d) Trichodesmium sp. as seen under a microscope.