es iii lec notes importance of ecology

8/6/2019 ES III Lec Notes Importance of Ecology

http://slidepdf.com/reader/full/es-iii-lec-notes-importance-of-ecology 1/3

Science Department, Holistic Education and Development Center, 2011-2012 of 3

ENVIRONMENTAL SCIENCE HS III LECTURE NOTES

WHY AND HOW DO WE STUDY ECOLOGY?

What is ecology?

From two Greek words: “ο ἶ κος” which means ‘house’ and “λογία,” which means ‘study of’

Ecology is the study of human kind’s house (the planet Earth)

Ecology is a study of interactions:

Living things with other living thingsLiving things with non-living things

Ecology is an umbrella science. In order to effectively address real-world problems, ecology must use other sciences. An

example is shown below:

Are there levels to the study of ecology?

The study of ecology occurs at five levels: behavioral ecology, population ecology, community ecology, ecosystems ecology,

and biosphere ecology

Behavioral ecology

Deals with the actions of an organism and how such actions contribute to its survival, reproduction and growth

Behavioral ecology studies problems such as:

Why are some species social while others are solitary?

Why do some bird species practice a polyandrous (one female, many males) mating system?

What do flying lizards eat?

Population ecology

A population is a group of individuals belonging to the same species and interacting in the same space and time

Individuals belong to the same species if they can successfully reproduce (this is known as the biological species

concept)

Population ecology deals with managing the abundance and density of populationsAbundance – total number of individuals in a population

Density – Abundance divided by habitat area

Population ecology studies problems such as:

What factors contribute to the survival or extinction of populations?

What limits the abundance of a population? (limited by food? By competitors? By natural enemies?)

How do populations increase and why do they decrease in number?

Proposal to use the water of the

Tungtong River for domestic use in

neighboring residential areas

HYDROLOGY

(study of movement, distribution

and quality of water)

How much water does the river

hold?

Is there enough water for

domestic use throughout the

year? (The river will not dry up?)

Is the water quality good enough

for human consumption?

BIOGEOGRAPHY

(study of distribution of animal andplant species in space and time)

How will the reduced water flow

affect the river’s biota?

Will there be enough water for

both humans and wildlife?

SOCIAL SCIENCE

(formal study of society)

How will the water use affect the200 households of informal

settlers in the river banks?

How will they reach to

commercialization of a resource

that they are already using for

free?

ECONOMICS

(study of the production,

distribution, and consumption of

goods and services)

Will the consumers be willing to

pay when they already have

MWSS?Will the project be economical?

TOXICOLOGY

(study of effects of chemicals on

living things)

Will the proposed project produce

environmental pollutants?

If so, how will these affect native

wildlife?

ENVIRONMENTAL ENGINEERING

(study of the application of

engineering principles to the

improvement of nature)

How much physical alteration of

the environment will the project

entail?

Will the construction of the

physical plant adversely affect

native wildlife?




Community ecology

A community is a group of populations interacting in the same space and time.

Community ecology deals with the biodiversity of an area (bio- life; diversity- variation).

Diversity may be defined in terms of:

Species richness – total number of species in an area

Species evenness – the degree of representation that each species has to the total count

Population ecology studies problems such as:Why is an area more diverse than another?

How is stability related to diversity? Is a community more stable if it is more diverse?

Ecosystems ecology

An ecosystem is an area in which communities interact with the non-living factors in their environment.

Ecosystems ecology deals with the cycle of nutrients and the flow of energy in an area.

Nutrients cycle – no new matter is formed; each particle of matter is simply cycled over and over

Energy flows – energy once used, cannot be re-used; this is because it is converted to some other form

An ecosystem is the sum total of all biogeochemical cycles in an area.

Consider the two communities of grasslands below:

Grassland X

Grass

SpeciesAbundance

A 100

B 1

C 1

D 1

E 1

F 1

Grassland Y

Grass

SpeciesAbundance

A 100

B 100

C 100

D 100

Grassland X has a species

richness of 6 while Grassland Y

has a richness of 4. Does this

automatically make X more

diverse than Y?

We have to consider evenness when assessing biodiversity. Which community is more

even? (species are better represented in the total)

If a casual visitor looks at Grassland X, how many species would he see? Chances are, he

will only see Species A since there are 100 individuals of that species (an overwhelming

majority). It would take a more careful search to discover the other species since there is

only 1 individual for each.

The opposite is true for Grassland Y. The casual visitor would see all the species at once

since there are 100 individuals for each (they are well represented). Hence, Grassland Y is

said to be more even and more diverse than Grassland X.

A biogeochemical cycle is a participation of the three components that play a role in the cycle of matter. The

water cycle shown below is a good example.

Bio

Geo

Chemical

The chemical component refers

to the chemical and/or physical

transformations that the

matter undergoes as it is cycled

between the bio and geo

compartments.




Ecosystems ecology deals with questions like:

How does the length of day affect the productivity of an area?

How does soil microbe diversity affect the cycle of phosphorus in different kinds of forests?

Biosphere ecology

The biosphere refers to the entire area of the Earth that can support life.

Biosphere ecology deals with issues that affect the entire Earth. These include climate change and global warming,

coral reef bleaching, and ozone layer depletion.

How do we study ecology?

Ecological studies involve spatial and temporal scales which dictate each study’s methodology. These scales are

determined by the subject of the study.

The spatial scale refers to the geographical extent of the study. The spatial scale addresses questions such as:

Where is the organism?

How large an area does it inhabit?

The temporal scale refers to the study’s timeline. The temporal scale addresses questions such as:

How long is the organism’s lifespan? Which part of the organism’s lifespan is under study?

Will the organism be studied for the entire lifespan or only during particular periods?

Both temporal and spatial scales dictate the material resources needed for the successful completion of an ecological study.

Why do we study ecology?

The study of ecology is of paramount importance since it involves man’s ultimate resource- the planet Earth. If we don’t

exert the effort to understand our Earth, then we will end up using it wrongly. We will end up becoming the endangered

species.

Any problem must be approached from all levels of ecology in order to gain a holistic understanding. Consider again the

proposal of using the Tungtong River as a source of water for domestic use.

Failure to consider just one level of ecology may lead to disastrous results as the following articles exemplify:

http://geography.about.com/od/specificplacesofinterest/a/nile.htm

http://sitemaker.umich.edu/sec004_gp5/the_aswan_dam_disadvantages

Proposal to use the water of the

Tungtong River for domestic use in

neighboring residential areas

BEHAVIORAL ECOLOGY

Will the reduced water levels

affect the movement of fish

species?

Will the presence of the water

facility impact on the nesting

habits of birds?

POPULATION ECOLOGY

Will the reduced water flow affect

the abundance of amphibians?

Amphibians, especially frogs,

make up a large portion of a

kingfisher’ diet. If the abundance

of frogs is affected, then how will

this impact on the abundance of

kingfisher populations?

COMMUNITY ECOLOGY

Will the construction of the water

facility impact negatively on the

area’s biodiversity?

Where can the facility be

constructed such that its negative

impacts on biodiversity be

minimized?

ECOSYSTEMS ECOLOGY

Will the water facility introduce

toxins into the water?

How will these toxins affect native

wildlife?

How will the reduced water flow

affect the deposition of nutrient-

rich sediments in the downstream

portion of the river?

BIOSPHERE ECOLOGY

How will the use of this river

affect the hydrology of the greater

area? Of Rizal? Of Luzon?

How can the case of this river be

used in managing freshwater

ecosystems around the world?







es iii lec notes importance of ecology

Documents