IB 105 Lectures 9-10

1. What factors contribute to the low life expectancy in many countries?
Any factor (limiting factor) in the environment influencing carrying capacity.

Four main factors:
Raw material availability
Energy availability
Waste accumulation and disposal
Organism interaction

2. Know the story of Easter Island and the reasons for their population crash.
Without the trees, the rich soil washed into the ocean
now difficult to grow crops; carrying capacity of island decreased
3. What is the difference between local and total carrying capacity? What is the result of using renewable resources way beyond their sustainable limit?
In many parts of the world, food availability is the first limiting factor
– 1 billion people malnourished
– conversion of forests to agriculture OK in short term, but lowers productivity in long term

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Other parts of the world have excess food, but use tremendous amounts of fossil fuels

4. Understand how energy flows through the food web
Food Chain — Passage of energy from one trophic level to the next due to one organism consuming another.
Understand bioaccumulation and how that can affect human populations
Biomagnification – an accumulation of a contaminant in an organism at a higher trophic level
1.Be familiar with the system for classifying living things. Know the biological species concept.
Classification ranked according to
– similarity
– common ancestry
Species are groups of interbreeding organisms.-Biological Species Concept
2.Be able to define biological diversity and scales of diversity.
“the variety and variability among living organisms and the ecological complexes in which they occur”

Ecosystem level diversity – Variation in ecosystems across a
landscape or region.
Community level diversity – Variation in species assemblages
based on variation in habitat within an ecosystem type.
Species diversity – The number of species in a given community.
Genetic diversity – Amount of genetic variation within or among populations of a given species.

3.Know the relative diversity of different animal phyla
34 Animal Phyla
4.Understand historical versus current extinction rates.
slide 32
5.Understand 2 principle ways that nature can advance science
1) Nature provides compounds of immense
importance to science and medicine
2) Nature provides inspiration for a wide
variety of scientific disciplines
6.Understand the tragedy of the commons.
See slide 35
concept of ecosystem engineers
Influence communities by physically modifying an ecosystem

Beaver : Transforms its territory from a stream to a small pond or swamp