Ecology and Evolution

Introduction (cont.)

• Ecological Revolution

Darwin 1859Origin of Species

Haeckel 1870sBroaden’s “Ecology”

IndustrialRevolution

Human Population Explosion ↑Materialism ↑Resource exploitation ↓Habitat (Environmental) Quality

↑Need for understanding human impact on planetincluding studying organisms and their surroundings

N

timei.r.

Biological Hierarchies

Ecological Revolution at all scales of ecological hierarchy.

Habitat – place or physical setting in which and organism lives

… and at all levels ofspecies diversity whenecologists take into accountthe evolutionary relationshipsamong organisms.

Evolutionary hierarchy

How does the physical (abiotic) environment affect life on earth?

• Concept behind the idea of the habitat:– The abiotic environment tends to place

constraints on life.– example:

• blood and tissues of vertebrates tend to freeze above temperatures found in antarctic waters.

Notothenoid fish-1.9° Cglycopeptide and peptide antifreeze compoundsOuter-tissues have ice on them and the spleen

Biology = solutions

Other constraints• Gravity

– solutions:– Flight: wings, metabolic level– Gliding: mammals, frogs, snakes– Bones

• Arid Environments (no water for photosynthesis)

– solutions:– Cactus: waxy outer covering, – stomata, ↑storage capacity, – suberized roots etc.

Main points

• Live exists in constant tension with its abiotic, physical surroundings (habitat)

• Tolerance for extremes for chance to reproduce.Reproduction

Growth and repair

Survive and maintainEnergy available

Life and Ecosystems are in a state of non-equilibrium

Consideration of some abiotic elements important for life

A. Water1. Abundant on Earth2. Excellent solvent3. Facilitates the movement of many organisms4. Main ingredient in photosynthesis5. Remains in liquid state over a large range of

temperatures6. Resists change in state

1. to freeze: remove 80cal/g2. to evaporate: add 500cal/g

7. Thermal inertia8. Density and Temperature

Density and temperature of water

• Substance X– cools becomes more

dense

• Water– cools becomes more

dense to about 4°– then expands! (ice

floats)

dens

ity

temp4°

Why important?Bottoms of bodies of water do not freezefloating layer of ice + layer of snow = insulation

dormant plants and reproductive bodies

Excellent solvent

• Natural waters contain dissolved substances that are building blocks of life

B. SolutesNa, Cl, Mg, SO4

N – nucleic acids, proteinP – na, phospholipids, boneS – proteinsK – solute in animal cellsCa – bone, plant structuresFe – Proteins (hemeglobin)

C. Carbon and Oxygen

• solutes that receive special mention– Immediately tied to life via:

• acidity• respiration and photosynthetic reactions

D. Light and Heat• Sources of heat:

– Sun– Geothermal– Metabolic