Levels of Ecological Studies:

1. Organism ecology – individuals; behavioral (diet of a carnivorous fish; defense mechanisms of a flowering plant)

2. Population ecology – groups of individuals of the same species; growth models; distribution (survey for a fish species in the Tungtong River; effects of a household cleaning agent on growth and devopment of butterflies)

3. Community ecology – interacting populations (competition models between lions and hyenas; survey of invertebrates in river bed)

4. Ecosystem ecology – biome studies (effect of acid rain on forests; effect of cattle grazing on grasslands)

5. Biosphere ecology – world-wide studies (global warming)

Levels of Ecological Studies:

For Asian Elephants, at what age does mortality rate begin to override birth rate?

What is the effect of rising sea levels to coastal communities?

Which natural predators can be used to control populations of crown-of-thorns starfish?

How does a bee communicate the location of a flower patch to the rest of the colony?

How effective is the newly designed catalytic converter for car mufflers in lessening carbon dioxide emissions?

Ecological methods of study take into consideration:

1. Spatial factors

2. Temporal factors

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The techniques used by ecologists to study the microsnail are very different from that of the Philippine Eagle Owl. The differences are determined by the spatial and temporal conditions characterizing the species. These would include capturing methods, documentation and measurement, tagging and tracking, wild observation, and others.

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Why study environmental science?

Some common ecosystem services:

1. Fresh air 2. Clean water3. Stable land4. Food

5. Medicines6. Clothing7. Beauty

Environmental science focuses on preserving the environment because of the benefits it gives human society. Such benefits are known as ecosystem services. These range from the very practical (food, water) to the sublime (the sparkling beauty of a dragonfly’s wings). The most critical of these services (known as key essential services) are necessary for the continuation of life on Earth. Destroy them and life on Earth, as we know it, will not be possible. For more on ecosystem services, refer to Figure 1-3 p. 8.

What is the importance of genetics in the study of the environment?

1. The problem with inbreeding – inbreeding (the reproduction between closely related individuals) brings out rare genetic diseases

2. The concept of critical population size – wild populations must maintain a critical population size in that there should be enough individuals to avoid inbreeding. A population that falls below its critical size is doomed.

Found only in the Russian Far East and North East China, the Amur Leopard (Panthera pardus orientalis) is now at the brink of extinction. The threats of habitat destruction and poaching has taken 2nd place to inbreeding. With less than 40 individuals in the wild, adult leopards are producing cubs prone to rare genetic diseases. (Image at left from www.altaconservation.org)

r-select K-select

Adult size Small Large

Development Fast Slow

Parental care Absent Present

Reproductive strategy Semelparous Iteroparous

Life span Short Long

Survivorship curve Type III Type I

Growth model J-curve S-curve

Mortality rate Death favors the young Death favors the old

What are life history traits?

These are traits which nature has selected as evolutionarily stable strategies for survival (ESS). Using this scheme, an ecologist may classify organisms as r-selected or K-selected.

K-select organisms VS. r-select (Read p 112 of textbook for more info)

Survivorship Curves

Survivorship Curves

Growth models

What do we mean by niche?

1. Diet – trophic strategy

2. Habitat – range vs territory

3. Niche as the functional role of an organism• Rivet vs Redundancy community models• Resistant vs Resilient communities