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Lecture 3

Lecture 3 - Diversity of Life and Prokaryotes

Biology (Sci)
Course Code
BIOL 111
Irene Gregory- Eaves

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Lecture 3
Diversity of Life and Prokaryotes
Prokaryotes first arose in the Precambrian Era.
Diversity – what is it, how it is measured and which group is most diverse
What is diversity?
1. Genetic Variation (differences within a species)
2. Species composition
3. Interactions within and between ecosystems
Species diversity – Reserved for indices that measure both the number of species in
a habitat as well as their relative abundances
Diverse environments are on the whole better than non-diverse environments.
1.5 million species are NAMED. About 13,000 new species found a year, 3000 of
these are synonyms (described already but not confirmed).
50,000 tree species*160 species of insects unique to a tree (screw it there could not
be an exact value or one that’s even close)
According to May in 2002, taxonomists estimate 3-100 million eukaryotic species
(extant = living today) (only 10,000 species of bacteria are found, but could range
up to 100s of millions)
99% of all species that existed on Earth are dead.
Warmer, wetter = higher diversity
Area and Diversity
Doubling the living area increases number of species by 10-25%.
Arthropods are by far the most diverse, followed by plants.
Only 4% of life has spines and fishes are the most diverse of animals with spine.
Other measure of divsersity
Genetic diversity = measure of genetic distance (evolutionary separation)
Functional diversity = shape, ways of getting energy, etc
Likely 7-10 million extant species. We like vertebrates and plants (hate bugs).
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