Chapter 3 IN PEARSON book

“The trouble with ecology is that you never know where to

start because every thing affects everything else.” –

Robert Heinlein “Farmer in the Sky”

Welcome to Ecology!

Biological Sciences

Earth SciencesPhysical Sciences

Ecology

“As an area of scientific study, ecology incorporates the hypothetico-deductive approach, using observations and experiments to test hypothetical explanations of ecological phenomena… ecologists face extraordinary challenges in their research because of the complexity of their questions, the diversity of their subjects and the large expanse of time and space over which studies must be conducted. Ecological questions from a continuum with those from other areas of biology, including genetics, evolution, physiology and behavior, as well as those from other sciences, such as chemistry, physics, geology and meteorology. “

Brainstorm session

What does “bio” mean? What does “eco”

mean? What do you think we are going to

study in ecology?

What were some examples of ecology

concepts in the movie: The Future of Food?

Ecology

Ecology is the study of the relationships between organisms and their physical and biotic environment:

“Organisms respond to their environments and can also change their environments, producing and ever changing, dynamic biosphere”. – pg 65

O2

Nutrients

CO2

Learning Goals for this Unit

• Recognizing the various levels of ecological organization

• Explain matter and energy’s interdependence in nature.

• Understanding how organisms get the energy the need to survive;

looking at food chains and food webs

• Describing how nutrient availability relates to the primary

productivity

• Understanding a producers means of obtaining energy through

photosynthesis

• Explaining how ATP is useful in cells

Living organisms can be studied at different levels of complexity.

From least to most complex, these levels are (in an ecological context):

Individual

Population

Community

Ecosystem

Biome

Biosphere

Ecological Levels of Organization

Biosphere

Biome

Ecosystem

Community

Population

Individual

BiosphereBiosphere

Ecosystems

Communities

Populations

Organisms

First Level:First Level:•Organism: A living thing.

8

Second Level:Second Level:•Population:

A group of

organisms, all of

the SAME

SPECIES

9

Third Level:Third Level:•Community:

Made up of different species living in the same place at the same time.

10

Fourth Level:Fourth Level:•Ecosystem:

Made up of different species AND the abiotic factors of that habitat

11

Fifth Level

•Biome:A group of

ecosystems that

share similar climates

and types of

organisms. (biomes

share similar climates

– “B before C”)

The biosphere is the region within which all living things are found on Earth.

It is the narrow belt around the Earth extending from the bottom of the oceans to the upper atmosphere.

Sixth Level: The Biosphere

What level of Organization?

14

Population

A community is a naturally occurring group of organisms living together as an ecological entity; the biological part of the ecosystem.

What level of Organization?

A nudibranch snail feeding on rock

encrusting organisms

What level of organization?

Organism

What level of Organization?

17

Ecosystem

An ecosystem encompasses the physical environment and the community.

Components of an Ecosystem

Community

Physical environment

Physical environment

Community

Abiotic

factorsatmosphere,

soil,

water,

wind speed

wind direction,

current velocity

Biotic factorscompetitors, symbionts, predators, parasites, pathogens

Ecosystem

Ecosystems Light intensity varies

Flow rate varies Rainfall level varies

An ecosystem includes:all of the organisms(the community) …

and their physical environment.

There are many different sorts of ecosystems from natural to artificial, and they range in size from large to small.

Still water habitatFast flowing water habitat

Rock habitat Stream bank habitat

21

Population

What level of Organization?

•Ecology can be divided into four increasingly

comprehensive levels

Organismal ecology Population ecology Community ecology Ecosystem ecology

A Hierarchy of Interactions

Hierarchy of Interactions:

Organismal Ecology

Is concerned with the evolutionary adaptations that enable individual organisms to meet the challenges posed by their abiotic environments

Figure 18.4a

Population Ecology

Is concerned with populations, groups of individuals of the same species living in the same area

Concentrates mainly on factors that affect population density and growth

Figure 18.4b

Community Ecology

Is concerned with communities, assemblages of populations of different species

Focuses on how interactions between species affect community structure and organization

Figure 18.4c

Ecosystem Ecology

Is concerned with ecosystems, which include all the abiotic factors in addition to the community of species in a certain area

Focuses on energy flow and the cycling of chemicals among the various abiotic and biotic factors

Figure 18.4d

Ecology vs. Environmental Science• The science of ecology can provide understanding behind

some environmental problems or concerns BUT does not

involve the decision making process on solving those

problems.

• Doesn’t include: politics, economics, and ethical views to

environmental problems

• Example: Global climate change

• ECOLOGY INVOLVED: how animals change to adapt to

different changes in climate

• OTHER FACTORS: How have humans influenced this

change in climate and what can we do to slow change?

Two environmental components when studying

ecology:

• ABIOTIC FACTORS:

• BIOTIC FACTORS:

Abiotic or Biotic?Abiotic or Biotic?

30BioticBiotic

31

Abiotic or Biotic?Abiotic or Biotic?

AbioticAbiotic

32

Abiotic or Biotic?Abiotic or Biotic?

AbioticAbiotic

Abiotic factors to consider:

Sunlight

• Solar energy powers nearly all ecosystems

Water

• Aquatic organisms face problems with water vs salt ions balance

• Terrestrial organisms main water problem is dessication

Wind

• Organisms such as plants depend on wind to disperse pollen and seeds (or nutrients blown to them).

Temperature

• It’s effect on an organisms metabolism

The physical environment refers to the physical surroundings of any organism, including:

the medium, e.g. water

substrate, e.g. soil

climatic (atmospheric) conditions

light …

and other physical properties.

Environments

Figure 18.8

What is the

connection between

abiotic factors and

distribution of species

(biotic)?

•Range of tolerance

• Every organism/population

thrives in an optimal range of

abiotic factors

• Outside of this range, less

numbers of the organism

Po

pu

lati

on

siz

e

Low High Temperature

Zone ofintolerance

Zone ofphysiological stress

Optimum range Zone ofphysiological stress

Zone ofintolerance

Noorganisms

Feworganisms

Lower limitof tolerance

Abundance of organismsFew

organismsNo

organisms

Upper limitof tolerance

Energy, Producers, and ConsumersWhen do you use energy?

Primary Producers

AUTOTROPHS

plants, certain bacteria, & algae

Where do Primary Producers get their energy?

• PHOTOSYNTHESIS • CHEMOSYNTHESIS

• Discovered 35 yrs ago

when investigating

volcanic vents in total

darkness.