Lecture 1:

What is Ecology?

Why it is important for NRM?

The three inter-related global challenges to sustainable development

Sustainability

• Major components:

– Environmental

– Economic

– Social

– Political

Asserts there is a 'premium' on a cautious andconservative approach to human interventions in thenatural environment where our understanding of thelikely consequences is limited and there are threats ofserious or irreversible damage to natural systems andprocesses

(As noted by Myers 1993 in Barbier, Burgess and Folke1994, 172).

Why Precautionary Principle in Natural Resources management?

Why ecology?

What is Ecology?

Ecology is a branch of science that systematically studies the relationships between living organisms (biotic component) and the physical and chemical environment (abiotict component) in which they live.

An ecosystem includes living organisms in a specified physical environment, the multitude of interactions between the organisms, and the non-biological factors in the physical environment that limit their growth and reproduction, such as air, water, minerals, and temperature.

The study of interactions between:Organisms and organismsOrganisms and environment

Why Study Ecology?

to provide a broader and deeper understanding of the natural process by which natural resources are created and maintained;

to understand some of the natural laws that impose limitations on the interaction of organisms (including humans) with their living and nonliving environment;

• to show the specific ways in which human interaction with nature has been incompatible, and

to identify some of the important links between ecology and economics, two disciplines which are imperative for a holistic view of natural resource problems and issues.

Why Study Ecology?

Ecological studies give us the scientific foundations for our understanding of natural resources (agriculture, forestry, fisheries etc.);

Ecology also gives us the basis for predicting, preventing and remedying ecological problems, pollution etc.

Ecology also help us to understand the likely consequences of environmental interventions and provide the rationale underpinning biological conservation.

Ecology?

• Ecology is an integrated and dynamic study of the environment.

To study Ecology involves…

• For non-living (abiotic)– Climatology

– Hydrology

– Oceanography

– Physics

– Chemistry

– Geology

– soil analysis, etc.

For living (biotic) animal behavior

Taxonomy

Physiology

mathematics (population studies)

etc.

• Biosphere

• Ecosystems

• Communities

• Populations

• Organisms

• Organs

• Tissues

• Cells

• Genes

ECOSYSTEM LEVELSingharaja forest

COMMUNITY LEVELAll organisms inSingharaja forest

POPULATION LEVELGroup of flying foxes

ORGANISM LEVELFlying fox

ORGAN SYSTEM LEVELNervous system

ORGAN LEVELBrain

BrainSpinal cord

Nerve

TISSUE LEVELNervous tissue

CELLULAR LEVELNerve cell

MOLECULAR LEVELMolecule of DNA

Genes

Levels of organization from genes to

ecosystems

ECOLOGY

Levels of Organization

Individual- one organism (living)

Ex a sambar

Population- groups of individuals that belong to the species and live in the same area (defined area) (living-living same species) and usually isolated to some degree from other similar groups

Ex many sambar

Levels of Organization

Community- groups of different populations (more than one population or different groups of species) and coexist in the same habitat or area and interact through trophicand spatial relationships

Ex many groups of sambar, trees, grass, tigers (all living)

Ecosystem- a community of organisms and their physical environment interacting as an ecological unit. All organisms in a particular area along with the nonliving (living and nonliving)

Ex many groups of sambar, trees, grass, tigers, rocks, water, mountains

Levels of Organization

Biome- group of ecosystems that have the same climate and similar dominant communities

Biomes: tropical rain forest, tropical dry forest, tropical savannah, temperate grassland, desert, temperate woodland and shrubland, temperate forest, northwestern coniferous forest, boreal forest (taiga), tundra, mountains and ice caps

Biosphere- all of the planet where life exists, includes land, water, and, air

Life extends 8 km up and 11 km below the surface

Levels of Organization

In an ecosystem, organisms live in a habitat and organisms fit into a Niche of the environment.

Habitat vs Niche

Habitat - an area where an organism lives

Niche - an organisms role in its environmentThe long version full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditions. Includes where in the food chain it is, where an organism feeds

Habitat is like an address in an ecosystem and a nicheis like an occupation in an ecosystem.

Niche

• Niche: The role or job that each species performs within an ecosystem. This role could be as a decomposer, a consumer, a producer, or a combination of these.

Habitat

• Habitat: An area that supports a particular species by providing survival essentials such as food, water,nutrients and shelter. Polar bear habitat and jack pine habitat are two examples.

Population, communities and ecosystems are terms which have precise meanings in ecology.

Did you understand the terms?

Take home quiz No 1:

Explain what do you understand by the terms population, community, ecosystem, niche, habitat and email to me (ngpkumara@gmail.com)

Terms

Geological history

Continental drift theory

Tea, 3.4% Rubber,

1.8%Coconut,

6.0%Other

perennial

crops,

11.0%

Paddy,

8.8%

Other non

perennial

crops, 1.5%

Closed

canopy

natural

forests,

22.4%

Sparse

forests,

7.2%

Forest

plantations,

1.4%

Homegarde

ns, 14.8%

Other land

uses, 21.5%

Sub Class

Magnoliidae 8 8 100 38 18 47.4

Hamamelidae 11 2 18.2 24 4 16.7

Caryophyllidae 3 3 100 14 12 85.7

Dilleniidae 13 10 76.9 78 34 43.6

Rosidae 18 17 94.4 112 57 50.9

Asteridae 11 10 90.9 47 30 63.8

Alismatidae 4 4 100 16 7 43.8

Arecidae 4 3 75 5 4 80

Commelinidae 7 6 85.7 16 8 50

Zingiberidae 2 2 100 8 5 62.5

Liliidae 2 2 100 19 10 52.6

83 67 80.7 377 189 50.1

No of

Families in

Sri Lanka

%No of

Orders in

the world

No of

Orders in

Sri Lanka

% No of

Families in

the world

Source: DSA Wijesundara

Approaches in Ecology?

Holistic approach (simultaneous considerations of all aspects)

Ecosystem approach – focus on exchange of energy and matters between living and non living components (functional relationships between organisms)

Community approach (synecology) (concept of succession and climax –biotic components)

Population approach (autecology) growth, maintenance and behavior of populations. Habitat, distribution, and evolution history.

Habitat approach

Evolutionary and historical approach (evolutionary ecology, palaeoecology, historical ecology)

Introduction to diversity and biodiversity

THE RULES OF ECOLOGY

• 1. Everything is connected to everything else.

• 2. Everything must go somewhere.

• 3. There is no such thing as a free lunch.

• To understand any system you must understand the next larger system.

“Nothing in biology makes sense except in the light of evolution” Theodosius Dobzhansky 1973

“The ecological theater and the evolutionary play”

“evolutionary events occur because of the relationships between an organismic unit and their environment”

tie between ecology and evolution

natural selection

1. The theory of natural selection is a truly fundamental unifying theory of life

2. A thorough appreciation of it is essential background for understanding evolutionary ecology

3. Natural Selection comes as close to being a “fact” as anything in biology

Natural Selection is synonymous with Evolution

- Evolution refers to temporal changes, whereas natural selection specifies one particular way in which these changes are brought about

- Evolution more specifically refers to a change in gene frequencies or descent with modification

SOCIETY

ENVIRONMENT

ECONOMY

ECONOMY

ENV’T

SOCIETY

TRADITIONALDECISION MAKING

ECOSYSTEM-BASEDDECISION MAKING

‘ECO-

SYSTEM

HEALTH’

References

Rebecca R. Sharitz, Lindsay R. Boring, David H. Van Lear and John E. Pinder (1992) Integrating Ecological Concepts with Natural Resource Management of Southern Forests. Ecological Applications Vol. 2, No. 3 (Aug., 1992), pp. 226-237.