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Ecology

SCBI 113 Essential Biology

Nuttaphon Onparn, PhD.

7 May 2009

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Outline

• Ecology

– Introduction

• Ecology and ecosystem

– Ecosystem

• Structure

• Function

• Interactions

– Biomes

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Introduction

• Ecology

– Greek oikos + logos (home + study)

• Distribution and abundance of organisms

and their interactions with their

environment.

– Ecosystem

• Unit of nature consists of living organisms

that interact and function together in the

environment.

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Ecology and Human

• Why do we need to know about ecology?

– To find food (hunter gatherers)

– To grow food (cultivation, agriculture)

– To understand nature (biologists, ecologists)

– Values

• Intrinsic values (scientific, pleasure)

• Extrinsic values (food, cloths, shelter, medicine;

money)

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Ecology and Evolution

• Ecology and evolution are closely related.

– Darwin

• Interactions between organisms and environment

lead to evolution.

– Natural selection

– Timeframe

• Ecological timescale (e.g. seasons, years)

• Evolutionary timescale (e.g. 106 years)

– Example of cats and mice

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Ecology and Environment

• Ecology raises public awareness

– Silent Spring

• Rachel Carson (1962)

• Overuse of DDT affected birds (non-target species)

– Public awareness

• Scientific discoveries

• Scientific communication

• Politicians/policy makers

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Ecosystem

• Ecosystem

– Structure and Function of ecosystem

• Structure

– Abiotic factors

– Biotic factors

• Function

– Species interactions

– Nutrient cycles

– Ecosystem services

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Interactions

• Level of interactions in ecosystem– Population level

• A group of individuals of the same species.– Human population

– Community level• A group of populations inhabit a particular area with

potential to interact.– Community on grassland

– Ecosystem level• All communities and their surrounding

– Forest ecosystem

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Abiotic Factors

• Abiotic factors

– Temperature

• Thermodynamics; range: 0-45oC;

• Thermophiles

• Ectotherms, endotherms

– Water

• Solvent of life

• Salt and freshwater

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Abiotic Factors

• Sunlight– Drive photosynthesis in green

organisms.

– Main source of energy for the planet.

• Wind– Moving air, amplifies effect of

temperature.

– Increase evaporation.

– Flgged morphology

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11“Flagging” of tree limb due to wind

12Doi Intanont (April 2, 2009)

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Abiotic Factors

• Rock and soil

– Nutrients and pH limit the distribution of plants,

and animals that associate with the plants.

• Climate

– Combination of effects from temperature, water,

sunlight, and wind.

• Global climate vs local climate

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Organisms and Environment

• How organisms respond to the environment?

– Physical factors can trigger responses in living

organisms.

• Organisms that respond well will be fitter.

• Examples

– Hibernation

– Estivation

– Migration

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Biotic Factors

• Structure: biotic factors

– Species diversity

– Species abundance

– Species distribution

– Trophic levels

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Trophic Levels

• Trophic levels

– Producers (plants, algae, cyanobacteria)

– Consumers

• Herbivores (eat plants)

• Carnivores (eat animals)

• Omnivores (eat both)

• Detritivores (eat detritus)

• Scavengers (eat remains)

– Decomposers

• Change organics to inorganics

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http://en.wikipedia.org/wiki/Image:Drosera_capensis_bend.JPG

http://en.wikipedia.org/wiki/Image:VFT_ne1.JPG

Venus flytrap (กาบหอยแครง)

Sundew (หยาดนํ�าคา้ง)

Species Interaction

• Interspecific interactions

– Predation

– Parasitism

– Disease

– Competition

– Mutualism

– Commensalism

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Ecosystem Services

• Ecosystem services

– Fundamental life-support services for all life on

Earth, that human and our technology cannot

replicates.

• Nutrient cycles

• Pollinations

• Detoxify natural substances

• Climate moderation

• Etc.

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Nutrient Cycles

• Nutrient cycles

– Carbon cycle

– Nitrogen cycle

– Phosphate cycle

– Water cycle

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Biomes

• Biomes

– A major biotic community characterized by the

dominant forms of plant life and the prevailing

climate.

• Total of all biomes/ecosystem = Earth (biosphere)

– Types of biomes

• Aquatic biomes

• Terrestrial biomes

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Aquatic Biomes

• Aquatic biomes– World’s major ecosystems

– Fresh or salt water (less than 1% or average 3% of salt)

• Coverage– 75% of Earth’s surface

• Impact– Rainfall

– World climate

– Oxygen and carbondioxide consumption and production

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Lake

Wetland

Stream and River

Estuary

Freshwater biomes

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Intertidal zone

Oceanic pelagic zone

Coral reef

Marine Benthic zone

Marine biomes

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Terrestrial Biomes

• Terrestrial biomes

– Biomes on land

– Climate determines type of terrestrial biomes.

• Climograph (precipitation and temperature)

– Vertical stratification

• Canopy, tree stratum, shrub, ground layer, litters, root

layer

– Various ecological niche

– Horizontal (ecotone)

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Journal

Trends in Ecology and

Evolution

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References

• Textbook

– Campbell, N. A. (2008). Biology. San Francisco, Pearson Benjamin Cummings.

• Internet

– Ecology, http://en.wikipedia.org/wiki/Ecology, retrieved May 2009

– Ecosystem, http://en.wikipedia.org/wiki/Ecosystem, retrieved May 2009

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