Unit 3 - What is Ecology?

A. BergeronBiology IIPCHS

What is Ecology?

As part of your reading assignment last night you learned about the definition of ecology.

What is the definition of ecology? Consider the questions in the four corners of the figure as you try to answer the question.

When your group is ready add your definition to the class concept map.

Do Now - Levels Within Levels

An ecosystem is a collection of all the organisms that live in a particular place, together with their nonliving, or physical, environment. Within an ecosystem, there are

several levels of organization. Your school and its grounds are similar to an ecosystem.

1. What living things are found in and around your school?2. What nonliving things are found in your school?3. Into what large groups are the students in your school

divided?4. Into what smaller groups are these large groups divided?5. Are these groups ever divided into even smaller groups? If

so, what are these groups?

Levels of Biological OrganizationOrganism (Individual): Any living thing (plant, animal, fungus)

Population (Species): A population of organisms that belong to the same species living in an area at the same timeCommunity: A collection of different populations living in a similar environment

Ecosystem: All ofthe living and non-living parts of a particular environment

Biosphere: Earth

Biome: A group of ecosystems that have the same climate and similar communities

Ecological Pyramids Foldable1. Follow my instructions to construct your foldable.

2. Lay your foldable out flat so that you can see all four quadrants. Choose three (3) quadrants to work with and leave the fourth quadrant blank.

3. Visit the “Food Web Resources” link on the webpage and as a group, choose one (1) food web with which to work.

4. Complete the activity by correctly placing the organism into its correct trophic level.! -Make a note of the type and number of trophic levels ! that are present in the food web that you have chosen.

5. When you’re finished, be sure to view the completed food web.

• An ecosystem consists of all the biotic factors (i.e. living organisms) living in a community– As well as all the abiotic (i.e. non-living) factors with

which they interact

• Regardless of an ecosystem’s size– Its dynamics involve two main processes: energy flow

and chemical cycling

Ecosystems

• Energy flows through ! ecosystems while matter cycles within them

Do Now - Pass It AlongEnergy flows in one direction through an ecosystem, from the sun or inorganic compounds to producers (organisms that can make their own food) through various levels of consumers (organisms that rely on other organisms for food). Your body gets the energy and materials it needs for growth and repair

from the foods you eat.

1.!Make a list of five foods that you like to eat. Indicate whether the food comes from a plant (producer) or an animal (consumer).

2.!Like many birds, chickens eat grains, which are seeds. Where do seeds come from?

3.!Meat comes from beef cattle. What do cattle eat?4.!Construct a diagram showing how one of your favorite foods

obtains its energy. Include as many levels as you can.

Energy Flow through an EcosystemProducers

Organisms that use sunlightor chemicals in the environment

to make their own food

Photoautotrophs Chemoautotrophs

Perform photosynthesis to produce carbohydrate and O2

Plants Photosyntheticbacteria

Chemosyntheticbacteria

Convert energy stored in thechemical bonds of inorganic

compounds into carbohydrate

Heterotrophs/ConsumersOrganisms that rely on other

organisms including producers for their energy and food supply

Herbivores Carnivores Omnivores Detritivores Decomposers

Energy Flow through an Ecosystem

Organisms that consume

plants

Organisms that consumeother animals

Organismsthat

consumeplants and

animals

Organisms that consume dead and

decaying matter (e.g. ants, beetles)

Organisms that break down

organic matter (e.g. bacteria,

fungus)

Autotrophs/Producers

Energy FLOWS through an Ecosystem– Entering as sunlight and exiting as heat

Figure 54.2

Microorganismsand other

detritivores

Detritus(Dead and Decaying

Matter)

Primary producers

Primary consumers

Secondaryconsumers

Tertiary consumers

Heat

Sun

Key

Chemical cyclingEnergy flow

Food chains-Links the trophic levels from producers to top carnivores

Quaternary consumers

Tertiary consumers

Secondary consumers

Primary consumers

Primary producers

Carnivore

Carnivore

Carnivore

Herbivore

Plant

Carnivore

Carnivore

Carnivore

Zooplankton

PhytoplanktonA terrestrial food chain A marine food chain

Food webs-A branching food chain with complex trophic interactions

Humans

Baleen whales

Crab-eater seals

Birds Fishes Squids

Leopardseals

Elephant seals

Smaller toothed whales

Sperm whales

Carnivorous plankton

Euphausids (krill)

Copepods

Phyto-plankton

Trophic level: An organism’s feeding level in an ecosystem

Examples of Food Chains and Food Webs

Do Now - Food Webs and Trophic Levels1. Identify the number of trophic levels in this food web.

2. The crab is located on which trophic level/s?

3. What is the role of the prawn in this aquatic food web? (Producer, 1st level consumer, etc.)

Ecological Pyramids Foldable6. Use the three flaps of your foldable to draw a pyramid of numbers, a pyramid of biomass, and a pyramid of energy for your chosen food web.! -You may estimate the amount of biomass and ! number of organisms in each trophic level but your ! pyramid MUST have the correct number of trophic ! levels and should accurately represent the food web! with which you worked!

! -The pyramid of energy should demonstrate your ! understanding of the 10% rule.7. When you are finished, fold the blank flap of your foldable underneath the other three flaps and glue the flaps together to finish your ecological pyramids foldable!

Ecological PyramidsPyramid of NumbersShows the relativenumber of individualorganisms at eachtrophic level.

Biomass PyramidRepresents the amount ofliving organic matter at each trophic level. Typically, thegreatest biomass is at the base of the pyramid.

Energy PyramidShows the relative amount of energy available at each trophic level. Organisms use about 10 percent of this energy for life processes. The rest is lost as heat.

Productivity and Energy Utilization• When a caterpillar feeds on a plant leaf

– Only about one-sixth of the energy in the leaf is used for secondary production

• The production efficiency of an organism– Is the fraction of energy stored in food that is not used

for respiration

Vegetarians (and Vegans) Shall Rule the World!

Ecological PyramidsEnergy Pyramid

Summarizes the energy loss from one trophic level to another 10% Rule - An average of 10% of the energy available in a particular trophic level is converted to biomass at the next trophic level

Ecological PyramidsBiomass Pyramid & Pyramid of Numbers

Represents the actual biomass in each trophic level

of an ecosystemMost biomass pyramids are“bottom-heavy” but some

aquatic ecosystem pyramids are “top-heavy.”

Illustrates the number of individuals present at each

trophic level of an ecosystem

Most biomass pyramids show a sharp decrease at successively higher trophic levels

Biomass Pyramids

Certain aquatic ecosystems have inverted biomass pyramids

Trophic level Dry weight(g/m2)

Primary producers

Tertiary consumers

Secondary consumers

Primary consumers

1.5

1137809

Trophic level Dry weight(g/m2)

Primary producers (phytoplankton)

Primary consumers (zooplankton) 21

4

Biological Magnification– Toxins concentrate at higher trophic levels because

at these levels biomass tends to be lower

Figure 54.23

Con

cent

ratio

n of

PC

Bs

Herringgull eggs124 ppm

Zooplankton 0.123 ppm

Phytoplankton 0.025 ppm

Lake trout 4.83 ppm

Smelt 1.04 ppm

C6H12O6 + 6 O2 --> 6 CO2 + 6 H2O + Energy

ATP + heat

6 CO2 + 6 H2O + Energy --> C6H12O6 + 6 O2

Sun + ATP

Cellular Respiration (Takes place in cytoplasm and mitochondria)

Photosynthesis (Takes place in chloroplasts)

1. Was the rate of carbon dioxide production a positive or negative number? What is the biological significance of the sign on this value?

Cell Respiration Lab Discussion QuestionsPlease answer the following questions on a separate piece of paper after you have finished collecting data from the lab.

2. Was the rate of oxygen production a positive or negative number? If so, what is the biological significance of this?

3. Do you have evidence that cellular respiration occurred in the yeast culture? Explain.

4. List three (3) factors that might influence the rate of carbon dioxide production or oxygen consumption in yeast. Explain how you think each will affect the rate?

Biogeochemical Cycles

• Cycling of materials between the environment and organisms

• Chemical and biological processes• Examples

– Carbon cycle– Water cycle– Nitrogen cycle

Plants obtain nitrogenfrom nitrogen-fixing

bacteria and pass it toother organisms through

the food chain

Do Now - Carbon Cycling through an Ecosystem

1. Identify three (3) sources of carbon dioxide within an ecosystem.

2. Identify three (3) “sinks” (a living or nonliving thing where CO2 is absorbed) within an ecosystem.

3. Use the animation to illustrate how a molecule of CO2 could cycle through an ecosystem.

Visit the The Carbon Cycle - Animated and the The Carbon Cycle - Tutorial links on the class website. Use this site to answer the following questions.

Carbon Cycle

Do Now - It’s Raining, It’s Pouring (The Water Cycle)

1. !When rain falls on the ground, it either soaks into the soil or runs across the surface of the soil. When rainwater runs across the land, what body of water might collect the rain?

3.!After the rain, the sun comes out and the land dries. Where does the water that had been on the land go? What is responsible for this movement?

Visit the The Water Cycle - Animated and the The Water Cycle - Quiz links on the class website. Use this site to answer the following questions.

2. From here, where might the water flow?

4. Construct a diagram that would illustrate all the places a molecule of water might go. Begin with a raindrop and end with a cloud. Use the links on the class website if you need help.

Water Cycle

Do Now - The Nitrogen CycleVisit the The Nitrogen Cycle - Animated on the class website. Use this site to answer the following questions.

1. Where is nitrogen (N2) found in an ecosystem? Can this N2 be used by living organisms?

2. Identify two (2) ways in which N2 can be converted into a form that can be used by living organisms.

3. Can you identify a biological molecule in a living organism that contains nitrogen?

4. Which type of organism is responsible for converting nitrogen in the atmosphere into a usable nitrogen containing compound?

5. What must happen in order for nitrogen containing compounds to return to the soil?

The Nitrogen Cycle

N2 in Atmosphere

NH3

NO3-

& NO2-

The Nitrogen Cycle

Nitrogen (N2) is found in amino acids (building block of proteins) and in nucleotides (building block of DNA and RNA)Organisms cannot utilize atmospheric nitrogen --> N2 must beconverted into NO3

- or NH4+ by bacteria that live in or on the

roots of certain types of plants

Nitrogen FixationNitrogen contributes the most to plant growth and crop yieldsGaseous nitrogen (approx. 80% of our atmosphere) cannot beutilized by plants --> Must be converted to NH4

+ or NO3-

Denitrifying bacteria return N2 to the atmosphere

Do Now - The Nitrogen CycleWhen you have finished answering all of the questions, please complete Online Activity 36.3 in the Biology: Exploring Life folder

Measuring the United States Carbon Footprint

Greenhouse Effect

Sunlight

Some heatescapesinto space

Greenhousegases trapsome heat

Atmosphere

Earth’s surface

Sunlight

Most direct sunlight

Sunlight

Sunlight

Sunlight

90°N North Pole

66.5°N

23.5°N

0°

23.5°S

66.5°S90°S South Pole

Arctic circle

Tropic of Cancer

Equator

Tropic of Capricorn

Arctic circle

Greenhouse Effect Different Latitudes

• Due to the increased burning of fossil fuels and other human activities– The concentration of atmospheric CO2 has been

steadily increasing

Figure 54.24

CO

2 con

cent

ratio

n (p

pm)

390

380

370

360

350

340

330

320

310

3001960 1965 1970 1975 1980 1985 1990 1995 2000 2005

1.05

0.90

0.75

0.60

0.45

0.30

0.15

0

−0.15

− 0.30

− 0.45

Tem

pera

ture

var

iatio

n (°

C)

Temperature

CO2

Year

Global Climate Change - Effect of CO2 on Climate

Average Global Temperature (1880-2008) -Compared to long-term average for each year

Do Now - Ecological Interactions

Open Online Activity 35.4 on the Biology: Exploring Life CD-ROM

Complete the activity and be prepared to discuss the differenttypes of ecological interactions that might take place within anecosystem

Bay-Breasted WarblerFeeds in the middlepart of the tree

Yellow-Rumped WarblerFeeds in the lower part of the tree andat the bases of the middle branches

Cape May WarblerFeeds at the tips of branchesnear the top of the tree

Spruce tree

Niches

A niche includes an organism’s habitat, its food sources, thetime of day at which it is most active, and other biotic (living) and abiotic (non-living) factors that are unique to the species.

Two (or more) species can rarely occupy the same niche for anextended period of time

Paramecium aurelia(Species 1)

Paramecium caudatum(Species 2)

Competitive Exclusion - Interspecies Competition

Competitive Exclusion - Interspecies Competition

Niche: The species’ “profession”; how the organism interacts with the biotic (living) and abiotic (non-living) factors in its’ environment

Competitive exclusion: Whentwo different species attemptto utilize the same niche andone species outcompetes (and usually eliminates) thesecond species

Interspecific competition: Occurs when two or more species compete for a resource that is in short supply

Do Now - Investigating Niches

1. What is a niche?

3. Can two different species live in/occupy the same niche?

2. List three (3) components of a niche.

Ecological Interactions Foldable

Define the interaction. How would you describe the interaction?

Identify an example of the interaction in nature.

Draw a picture/illustration of the interaction

All forms of Symbiosis - A close relationship between two or more

different species

Are both species harmed (-/-)? Does one species benefit while the other species is harmed (+/-)Does one species benefit but the other species is not affected? (+/o)?Do both species benefit (+/+)?

Competition (-/-)Predation (+/-)Commensalism (+/o)Parasitism (+/-)Mutualism (+/+)

Interspecies Interactions

Do Now - Fitting In• Organisms not only live together in ecological communities,

but they also constantly interact with one another. These interactions, which include predation and competition, help shape the ecosystem in which they live.

1. Based on your own experiences, define predation. Give one example of predation.

2. Based on your own experiences, define competition. Give one example of competition.

Year1850 1875 1900 1925

0

40

80

120

160

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3

6

9

Lynx

pop

ulat

ion

size

(th

ousa

nds)

Har

e po

pula

tion

size

(th

ousa

nds)

Lynx

Snowshoe hare

• Boom-and-bust cycles sre influenced by complex interactions between biotic

! (living) and abiotic (non-living) factors

Predator-Prey Interactions (+/-)

Predators catch and consume prey

Which types of factors might influence a populationof predators and prey over time?

Predator-Prey Interactions

Notice “lag time” betweenboom of prey and boom of predator populations

Parasitism (+/-)One organism benefits while harming another! -Parasite derives nourishment from host ! -The host is typically harmed as part of the interaction

Tapeworms are common examplesof parasites that infect humans

Tapeworms latch on to the wall of the intestine and absorb digestednutrients directly through their “skin”

Tapeworms are hermaphrodites andfertilized eggs are released throughthe feces of the host organism

Parasitism (+/-) - “The Brain-Jacking Worm”Spiny-headed acanthocephalans can infect a crustacean (i.e. crab) which typically avoids predators by hiding in dark areas and staying away from the surface of the water

The worms alter the brain chemistry of the host causing it to leave the dark areas and move to more well-lit locations wherepredators are present

Why does this occur?

Birds that feed on the crustacean serve as thefinal host for the acanthocephalon

The worm has to “convince” the crab to be eaten in order to infect the next host

The Nitrogen Cycle - An Example of Mutualism?

N2 in Atmosphere

NH3

NO3-

& NO2-

Nitrogen (N2) is found in amino acids (building block of proteins) and in nucleotides (building block of DNA and RNA)Organisms cannot utilize atmospheric nitrogen --> N2 must beconverted into NO3

- or NH4+ by bacteria that live in or on the

roots of certain types of plantsOnline Activity 36.3

Nitrogen FixationNitrogen contributes the most to plant growth and crop yieldsGaseous nitrogen (approx. 80% of our atmosphere) cannot beutilized by plants --> Must be converted to NH4

+ or NO3-

Denitrifying bacteria return N2 to the atmosphere

Ant acacias and acacia ants:another classic example of mutualism?

Mutualism (+/+)Both organisms/populations involved benefit from the interaction

Plants provide ants with food (protein & nectar) and a place to live (hollow thorns).

Ants kill insect herbivores that land on plant.

Ants also chew and kill any plant that touchesthe host plant (i.e. Acacia).

Often ants also clear the ground of vegetation in the vicinity of the plant.

In the absence of ants, most ant acacias will fail to thrive because of attacks from herbivores.

An Interesting Example of Mutualism (+/+)Boran (located in Kenya) people of Africa and the honeyguide (Indicator indicator) bird

The bird leads humans to bee colonies present in the area

It can take a search party approximately 9 hours to find a colonyon their own but only 3 hours when guided by the bird

Borans take the honey but leave the wax and larvae behind for the honeyguides to eat

Borans use smoke and fire to “dissuade” the bees from stingingthe search party

Mutualism in Leafcutter Ants

Leafcutter Ants in ActionLeafcutter Ants - The First Farmers?

Leafcutter ants “cut” leavesfrom neighboring trees andreturn them to the nest for“processing”Worker ants process the leafmaterial into a pulp which isfed to a fungus which inhabitstheir nestThe fungus converts the pulp into a protein and sugar mixturethat the ants feed on in order to survive

What ecological role are the bacteria playing in this ecosystem?

Commensalism (+/0)One species benefits while the other neither benefits nor is harmed from the interactionDifficult to characterize in nature because the interaction almostalways has an effect on both organismsCattle egrets feed on insects that are flushed out of the grassby water buffaloEgrets benefit from this interaction and water buffaloappear to be neither helpednor harmedInterestingly, water buffalomay benefit from the interactionas the birds feed on insects living on the cattle

Another Example of Commensalism (+/0)Clownfish hide from predators in the stinging tentacles of a sea anemone! -The clownfish is immune to the effects of the tentacles

The sea anemone does not benefit from the interaction but isnot harmed either

Do Now - Unit 3 Test ReviewTopics that We Covered as Part of this Unit:

1. Levels of Biological Organization2. Energy Flow vs. Nutrient Cycling3. Cell Respiration vs. Photosynthesis4. Food Chain vs. Food Web

a. Determining trophic level of a producer or consumerb. Determining role of consumer in the food chain

5. Ecological PyramidsA. Energy pyramid and the 10% ruleB. Biomass pyramidC. Pyramid of numbersD. Biological magnification

6. Nutrient CyclingA. Carbon cycleB. Water cycleC. Nitrogen cycle

7. Concept of the Niche and Competitive Exclusion8. Ecological interactions

A. Competition, parasitism, commensalism, predation, and mutualism