I. The goal of science is to:

•investigate and understand the natural world.

•explain events in the natural world.

•use those explanations to make useful predictions.

II. Science begins with observations.

A. Data = information gathered from

observations. There are 2 kinds:

1. Quantitative data involves numbers

(ex: counting, measuring)

2. Qualitative data is not as easily measured; it is important to be objective & avoid bias. (ex: color, shape, descriptions)

B. Observation vs. Inference

1. Observation– Using one or more senses (hearing, sight, touch, taste, smell) to gather information.

• Technology can extend

our senses.

(ex. microscope, telescope)

2. Inference—A logical interpretation based on

prior knowledge and experience.

Observation: The man is carrying a bag.

Inference: He just went to

the grocery store.

III. Hypotheses A. A hypothesis is

1. a possible explanation for a set of

observations or an answer to a scientific

question

2. a testable prediction [Must be able to test it!]

3. based on prior knowledge, logical inferences,

or imaginative guessing.

B. When a hypothesis is tested, the testing can

1. support the hypothesis

2. say it’s partly supported, but needs

revision

3. refute it.

You do not say the hypothesis is “right” or “wrong”; you accept it or reject it instead.

Unit 1: Ecology

I. What is Ecology?

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

*Uses scientific methods such as

observation, question, hypothesize, etc.

NOT just “read about”

II. Energy Flow

A. Primary source of energy for most

organisms = the sun B. Photosynthesis:

CO2 + H2O C6H12O6 + O2

6 CO2 + 6 H2O C6H12O6 + 6 O2

Sun’s energy

Sun’s energy

C. Producers--capture energy from sunlight / chemicals and use it to produce food

• a.k.a. autotrophs

• Two ways to produce own food:

1. Photosynthesis—energy comes from the sun

2. Chemosynthesis—energy comes from the chemical bonds of inorganic molecules

(Ex. sulfur bacteria)

Thought Question #1: (In Science

Notebook)

Name 4 different photosynthesizers.

Videoclip: Deep Sea Vents and Life’s Origins

D. Consumers--rely on other organisms for their energy and food supply; a.k.a. heterotrophs

Types of consumers:

Herbivore—eats only plants (cow, deer, caterpillar)

Carnivore--eats animals (snakes, owls)

Omnivore—eat both plants & animals (human, bear)

Detritivore—feed on dead plant & animal litter, but

leave behind unused energy & nutrients (earthworm,

crab)

Decomposer—complete decomposition by breaking

down organic matter (bacteria & fungi)

TQ #2 (In Science Notebook)

Create a food chain that represents four trophic levels.

Label the autotrophs, heterotrophs, producers,

consumers, herbivores, and carnivores. (HINT - think

about what eats what!)

Decomposers

III. Feeding Relationships

Energy flows in one direction; matter cycles

Energy flows through ecosystems

sun

producers (plants)

loss of

energy

loss of

energy

secondary

consumers

(carnivores)

primary consumers

(herbivores)

Ecosystem Light

Energy flow

Producers Consumers Decomposers

Heat

Chemical cycling

(biotic abiotic)

Energy and matter are neither created nor destroyed

Visual Summary 19.1

Energy flows through an ecosystem in one direction, beginning with solar energy.

1. This stored energy then passes through a food chain, a series of organisms that

successively eat one another.

2. The trophic level, or feeding level, of an organism is the number of food chain links between it and the ecosystem’s energy source.

Trophic Levels

Trophic Levels

Tertiary Consumer

Secondary Consumer

Primary Consumer

Producer

Decomposers

• A generalist is able to survive in a wide variety of environmental conditions and can make use of a variety of different resources.

--Ex: Heterotrophs with a varied diet, Omnivores • A specialist can only thrive in a narrow range

of environmental conditions, or has a limited diet. This helps reduce competition in a habitat.

--Ex: Koala eat only eucalyptus

• Ecological Equivalent—organisms that occupy similar niches, but live in different geographical regions.

Anteaters live in Aardvarks live in southern Mexico and Africa. South America.

Food Web = a network of food chains (List the organisms in one of the food chains.)

TQ #3:

In this food web,

make a chart and

label all the

producers,

primary

consumers,

secondary

consumers,

tertiary

consumers,

quaternary

consumers

Producers?

Primary Consumers?

Secondary Consumers?

Tertiary Consumers?

Quaternary Consumers?

• Keystone species—a species that has a disproportionate effect on its environment relative to its biomass.

Ex: Wolves in Yellowstone Park prey on elk. Without the wolves, the elk population would explode and destroy many plant species. The wolf is the keystone species.

IV. Ecological Pyramids

10 Percent Law: The energy available at each trophic level is about one-tenth the energy available from the trophic level below it. (90% loss at each energy level)

TQ #3: (In Science Notebook)

Examine the food chain below:

GRASS → COW → HUMAN

How many kilocalories (kcals) of grass are needed to

support 50 kcals of human?

Plant material eaten by caterpillar

Growth (new biomass; secondary production)

Cellular respiration

Assimilated

Feces

Not assimilated

100 J

33 J

67 J

200 J

Figure 55.10

Where does it go?

• Some is used for life activities (respiration, reproduction, movement)

• Some is lost as heat.

The base level of an ecological pyramid contains

▪ plant life ▪ the greatest number of individuals ▪ the greatest amount of potential food energy ▪ the greatest amount of biomass (dry weight).

Approximately 90% loss of energy at each trophic level

Energy

• Compare the pyramids of human vegetarians with that of human meat-eaters.

Figure 19.27

Secondary consumers

Primary consumers

Producers

Human vegetarians

Corn

(a)

Human meat-eaters

Cattle

Corn

(b)

V.

[Use the following information to answer the 3 questions.]

• All organisms need nitrogen to make amino acids / protein. But N2 in the air must be converted to a usable form. This process is called Nitrogen Fixation.

• N2 is triple-bonded, and we can’t break that bond.

• Nitrogen-fixing bacteria (found on the roots of plants called legumes) and nitrifying bacteria (found in soil) CAN break the triple bond.

• Nitrogen then combines with another element – such as oxygen or hydrogen; It is then said to be fixed. Plants incorporate it, and we then get Nitrogen through the food chain.

Legume Root

Nodules

Examples of legumes: Peas, beans,

clover, alfalfa

VI. Community Interactions

An Ecosystem

includes the living (biotic factors) and the nonliving (abiotic factors)

List 5 abiotic factors and

5 biotic factors.

Habitat = Where;

it is the location or surrounding where the organism lives

Niche = How; Its Role in the Community

--place in the food web

--temperature range it requires

--all physical, chemical, & biological resources it uses

--behavior (when it feeds & reproduces)

TQ #4: Read below. Summarize in your own words. What is happening?

In the 1800’s, the North American grey squirrel was brought to England. It used the same resources (food, space, habitat) as the native red squirrel. There was competition between the two species for the same resources. The red squirrel population is currently declining, and the grey squirrel population is increasing.

Competitive Exclusion

There are two possible outcomes of the competition:

1. One species is less capable and becomes extinct.

2. One species undergoes an evolutionary or behavioral shift towards a different ecological niche.

No 2 species can occupy the same niche

in the same habitat

Niche Specialization. Although all of these warblers have similar feeding habits, the intensity of competition is reduced because they search for insects on different parts of the tree.

TQ #5:

Examine the graph below. Write, in at least three

complete sentences, how this illustrates the competitive

exclusion principle.

A rainforest habitat has an incredibly large number of niches.

• Symbiosis = any relationship in which 2 species live closely together

• 3 main classifications:

– Mutualism – Commensalism – Parasitism NOTE TO STUDENT: You will not need to take notes until you see the chart—just read and listen until then.

Mutualism—both benefit

Clownfish & sea anemone Lichen = Alga + Fungus

Commensalism—one benefits; the other is neither helped nor harmed

Cow & Cattle Egret Shark & Remoras

Parasitism--One organism lives in/on another and harms it

Parasite – takes energy from the host; host is not usually killed.

Tapeworm

Type of Symbiosis Relationship Examples

Mutualism

Both benefit

Clownfish & Sea Anemone;

lichens (alga + fungus)

Commensalism One benefits; other is neither helped

nor harmed

Cow & Cattle Egret;

Shark & Remoras

Parasitism

One organism lives in/on another and

harms it

Tapeworm, ticks, fleas

VII. Ecological Succession • Primary Succession = development of an ecosystem in

an area that was not inhabited before.

• Begins with bare rock. Assume no soil is present when

this process begins. • Pioneer Species = the first species to colonize the area

(ex. mosses & lichens; they produce acids that break down the rock)

• These changes continue until a stable or climax

community is reached.

Copyright Pearson Prentice Hall

Example of Primary Succession:

1. A volcanic eruption has destroyed the previous ecosystem.

Copyright Pearson Prentice Hall

2. The first organisms to appear are lichens.

Copyright Pearson Prentice Hall

3. Mosses soon appear, and grasses take root in the thin layer of soil.

Copyright Pearson Prentice Hall

4. Eventually, tree seedlings and shrubs sprout among the plant community.

(can be hundreds of years)

Examples: -bare rock after a glacier melts -lava flow -landslide -strip mine

Examples of Primary Succession

Lava Flow

Glacier

Secondary Succession

• Occurs in communities that were established and then disturbed in some manner.

• Healthy soil is still present.

• Examples: Fire Hurricane Flood Plowing under

Secondary Succession

Before: Forest Fire After: New Growth