‘ENRICH YOUR RESUME’…

OUR Ecological Footprint - 13 1. Recycle; pay tax for it.2. Live near work; ride bike; minimize car use.3. Buy energy-efficient furnace.4. Programmable thermostat: winter/summer5. Turn off lights when leave room; unplug appliance6. Eat lower on food chain.7. Buy foods locally; avoid transport/energy costs.8. Use energy-efficient light bulbs.9. Reduce paper/plastic (and ALL) consumption.10. Reduce garbage + consumption of paper/plastic.11. Be a selective fish eater.12. Lengthen cycle of resource use; wear it out!13. Change lifestyle of greater consumption towards a lifestyle based on voluntary simplicity…

‘ENRICH YOUR RESUME’…

• THIS THURSDAY 4-5

• 217 NOYES LAB

• IB students describe ‘out-of-class’

opportunities

• Obtain info on how to find out about

these, when/how to apply

Last lab… 3rd Annual Ecology Symposium

Lab/TA evaluation

Chapter 25: Extinction + Conservation

Chapter 23Biodiversity

Chapter 24History andBiogeography

Objectives• Species diversity: different geographical scales• Factors at local vs. regional scales• Equilibrium theories of species diversity• Island Biogeography Theory• Regional-scale species diversity• Patterns and causes• Effect on local diversity• Latitudinal-scale species diversity• Continental/global scale and role of history Equilibrium in s.d. over time? Continental drift:

separation, joining, and biotic exchange Role of climatic change

Multiple scales of species diversity

• Local• Regional• Latitudinal• Continental• Global

• Ecological vs. Evolutionary Time…• Role of history

Many factors influence local and regional species diversity

Multiple scales of species diversity

• Local

• Regional

• Latitudinal

• Continental

• Global

Equilibrium theories: diversity reflects a balance between processes that add vs. remove species.• ***What processes add species?• speciation• immigration

• What processes subtract species?• extinction• emigration

• Differences in diversity between communities reflect differences in relative rates of these processes.

Equilibrium theory in continental communities: balance between speciation and extinction on regional scale

Equilibrium theory of island biogeography:# species = balance of immigration on a regional scale vs. extinction on local scale.

Islands closer to the mainland support more species because of higher immigration rates.

Larger islands support more species because of lower extinction rates.

*** What is the pattern? What explains it?

***Why do smaller islands have fewer species?

*** Do experimental results support ETIB?

Applications of Island Biogeography Theory (IBT) to:

• Terrestrial systems

e.g. mountain tops as islands

fragmented remnants as islands

• Design of nature reserves

Regional-scale patterns of diversity reflect:

• Habitat heterogeneity

• Suitability of physical conditions

• Isolation from centers of diversity

***What are three patterns in species diversity? What factor accounts for each pattern?

Comparing diversities of communities in similar habitats in different regions can reveal regional effects.

Saturation of local communities: test how local and regional diversity relate.

Variation in local species diversity depends on regional diversity.

***Are local communities saturated?

***What are major changes among regions from Tertiary to present? What accounts for them?

Mangrove vegetation is less diverse in the New World than the Old World tropics.

• Mangrove vegetation occupies a greater ecological range where it is most diverse.

Multiple scales of species diversity

• Local

• Regional

• Latitudinal

• Continenta

• Global

***What is latitudinal gradient in woody species diversity? What explains it?

Hypotheses to explain latitudinal gradient in species diversity

• Time• Energy• Productivity• Heterogeneity in space and time• (Vegetation and food complexity)• Predation• Competition/niches• Disturbance• Equilibrium models

Time hypothesis

• Tropics are older (and less disturbed??) --->more time to accumulate species.

• What happened to climate in the tropics during

glaciation?• What happened to species in the tropics during

glaciation? • Increased speciation from fragmentation?• Did extinction increase?

Many factors influence regional and localspecies diversity

Multiple scales of species diversity

• Local

• Regional

• Latitudinal

• Continental

• Global

Equilibrium theories: diversity reflects a balance between processes that add vs. remove species.

• Add species:• speciation• immigration

• Subtract species:• extinction• emigration

• Has regional species diversity been constant (in equilibrium) over long periods of time?

How do history + biogeography influence local communities and sp. diversity?

History of life is gauged by geologic time scale.

***Has diversity been constant?

Catastrophes --> major changes in direction of evolution

Asteroidimpact-->extinctions

Continental drift --> positions of continents change over geologic time.

Continental drift changed routes of dispersal via separation + joining.

Exchanges of biotas after joining of continents: e.g. The Panama land bridge

Lineages of ratite birds separated by fragmentation of Gondwana.

Organisms are not distributed uniformly over earth.

Phylogenetic effects

• traits shared by lineage irrespective of

environment

• e.g. marsupial model of reproduction

due to lineage of evolution

not due to environment in Australia

Wallace: Major zoogeographic regionsreflect long-term evolutionary isolation.

In contrast, similar environments among regions leads to convergent evolution.

Similar solutions to common problems…

How climatichistorydeterminesspeciesdistributions

Climate change shifts species diversity.

Local diversity as f(continental diversity).

Objectives• Species diversity: different geographical scales• Factors at local vs. regional scales• Equilibrium theories of species diversity• Island Biogeography Theory• Regional-scale species diversity• Patterns and causes• Effect on local diversity• Latitudinal-scale species diversity• Continental/global scale and role of history Equilibrium in s.d. over time? Continental drift:

separation, joining, and biotic exchange Role of climatic change

VocabularyChapter 24 History and Biogeography phylogenetic effects continental drift Pangaea Laurasia Gondwana vicariance Nearctic Palearctic Ethiopian Australian Oriental Neotropical mass extinctions land bridges convergence

Chapter 23 Biodiversity equilbrium theory Island biogeography theory regional diversity local diversity habitat selection environmental filters species sorting species pool ecological release alpha diversity beta diversity gamma diversity delta diversity niche space niche axis niche breadth niche overlap fundamental niche realized niche potential evapotranspiration pest pressure intermediate disturbance recruitment limitation