View
218
Download
0
Category
Tags:
Preview:
Citation preview
I. BIODIVERSITY (CH2, CH10, CH3 plus 3 “big articles”)
Intro to terms -Levels of biodiversity
A. History of biodiversity (and extinction) on earth
B. Where is biodiversity on earth and why?
C. How many species do we have? (Fri)
D. Extinction today
E. Relationships between ecosystem functioning, ecosystem services and biodiversity.
I. BIODIVERSITY
Intro to terms -Levels of biodiversity
Species diversity
II. Biodiversity
A. Species diversity
Genetic diversity
biomes, landscapes, ecosystems, habitats, niches, population
Community diversity
Your text…has table below
Despite all this we really focus on organism level.
Some more details…
In ecology… diversity is also more technically referred to as richness
What is the richness of each of these communities?
Is richness a great way of describing these two communities?
Species richness vs evenness
evenness=relative abundance of each species
A little more terminology…
Other ways of thinking about measuring diversity…
Alpha diversity is the within-habitat diversity
number of species per habitat
Beta diversity is the between-habitat diversity
number of different habitats
Gamma diversity= # species in a given large area like continent
A. History of biodiversity (and extinction) on earth
1. Precambrian before about 500mya
Ends with Cambrian explosion2. Paleozoic
Ends with the “End Permian” Extinction3. Mesozoic
Ends with the Cretaceous Extinction (K/T) 4. Cenozoic
5. Anthropocene
PRECAMBRIAN
PRECAMBRIAN
Oldest fossils are Prokaryotes-
What are Prokaryotes?Stromatolites (3.5bya)
Precambrian Ends with..Cambrian explosion about 500mya
Paleozoic Period about 500-250myaClimate-Moist SwampyPlants-ferns, mosses, horsetailGiant insects
Many diverse amphibians were large! 9ft
Science DailyTiktaalik roseae, an early tetrapodomorph (late Devonian period, ~380 M. y. ago) (Credit: Arthur Weasley, GNU Free Documentation licence)
And scary fish
nationalgeographic.com
Many Diverse Synapsids
A dicynodont
Thrinaxodon-cynodont
More Synapsids
Figure 23.4a
OTHERTETRAPODS
Reptiles(includingdinosaurs and birds)
Mammals
†Very late (non-mammalian)cynodonts
†Dimetrodon
Cyn
od
on
ts
Th
erapsid
s
Syn
apsid
s
Paleozoic Ends with the “End Permian Extinction” 250mya
Effect 90-96% of all species
Why?Huge amounts of lava oozing out of the earth Siberia- lasting millions of years…heat CO2 and sulfur dioxide
http://www.nationalgeographic.com/ngm/0009/feature4/
Mesozoic about 250-65mya•Dinos super diverse! •Mammals around..•Flying and pollinating insects begin to diversify with flowering plants
Mesozoic about 250-65mya•Dinos and diverse other reptiles! Mammals around..•Flying and pollinating insects begin to diversify with flowering plants
Mesozoic Ends with…Cretaceous Extinction event (K/T)! 65mya
Figure 23.10
Time (mya)
Paleozoic Mesozoic Cenozoic
542 488 444 416 359 299 251 200 145 65.5 0
E O S D C P Tr J PC N Q
0
100
200
300
400
500
600
700
800
900
1,000
1,100
EraPeriod
T
ota
l ex
tin
ctio
n r
ate
(fam
ilie
s p
er m
illi
on
yea
rs):
Nu
mb
er o
f fa
mil
ies:
0
5
10
15
20
25
Average species lives 1-10my
One Bryzoan has been on the planet for 85 my! (p34)
All Invertebrates Raup (1978) 11Marine Invertebrates Valentine (1970) 5–10Marine Animals Raup (1991) 4Marine Animals Sepkoski (1992) 5All Fossil Groups Simpson (1952) .5–5Mammals Martin (1993) 1Cenozoic Mammals Raup and Stanley (1978) 1–2Diatoms Van Valen 8Dinoflagellates Van Valen (1973) 13Planktonic Foraminifera Van Valen (1973) 7Cenozoic Bivalves Raup and Stanley (1978) 10Echinoderms Durham (1970) 6Silurian Graptolites Rickards (1977) 2Adapted from the book “extinction rates”, edited by Lawton, J, and May, R.[8] Wikipedia!!
http://www.planetunderpressure2012.net/images/anthropocene_cartoon.jpg
http://www.igbp.net/news/opinion/opinion/haveweenteredtheanthropocene.5.d8b4c3c12bf3be638a800
https://www.youtube.com/watch?v=fvgG-pxlobk
I. BIODIVERSITY
A. History of biodiversity (and extinction) on earth
B. Where is biodiversity on earth and why?
C. How many species do we have? (last Fri)
D. Extinction today (Today and Wed)
E. Relationships between ecosystem functioning, ecosystem services and biodiversity.
Biodiversity and where it is found..(Text 2.3)
•Land and water-do look at!
•Major biogeographic realms and ecoregions (Neotropics, Afrotropics, Nearctic..Western Indo Pacific etc…)
•Altitude and depth…
We will mostly focus on latitude
10 ha of forest in Brazil might have 300 species
10 ha of forest in US might have 30 species
Ants (Fischer 1960)
Brazil 222
Trinidad 134
Cuba 101
Utah 63
Iowa 73
Alaska 7
Arctic Alaska 3
Snakes
Mexico 293
U.S. 126
Canada 22
Freshwater fish
Lakes Victoria/Tanganyika/ Malawi each have about 1450 species
Amazon more than 1000
Central America has 456
North America 173
Marine inverts-planktonic crustaceans
Great Barrier Reef
50 genera of coral vs. 10 genera
Is the north or south end more diverse?
Marine bivalves
Butterflies
Lizards
Why do we see this pattern? (not so clearly ordered in your text-p38)
Hypotheses……
1.Energy
What does this mean? How might amount of energy reaching the earth affect the number of species?
More solar radiation->>more photosynthetic activity->>more resources->>more species
2. Evolutionary Time
What does this mean? Why might tropical areas be “older”?
All communities diversify over time because they accumulate species
Older communities will have more species than younger communities
tropical biotas ---”mature”
temperate and polar biotas ---”immature communities”
EX. Lake Baikal is one of the oldest lakes in the world
580 species of benthic invertebrates
Great Slave Lake Canada
4 species in (comparable area, latitude)
3. Spatial heterogeneity (i.e., topography)
Why might areas that vary lots in topography have more species?
The more complex the physical structure of the environment
1. Many different kinds of habitats.
But also..
2. Speciation is encouraged-populations are easily isolated from one another….
4. Climatic stability Why might a more stabile climate increase diversity?
means lower levels of extinction (museum of diversity)
Another factor that directly affects number of species is…
5. Size of area (Island Biogeography)
Note: may or may not relate to why tropics is hi in diversity…
Plants on small islands in Bahamas
Birds on lakes
Bats and caves Springs in Australia
Fig 10.3
I. BIODIVERSITY
A. History of biodiversity (and extinction) on earth
B. Where is biodiversity on earth and why?
C. How many species do we have?
E. O. Wilson-Mr. Biodiversity
The Ants
The Diversity of Life
http://www.youtube.com/watch?v=knLdKcx6VXk
History of our attempts to count species
• Linnaeus-1758-described about 12,000 species
• Number of described species today 2 million extant (your text p30)
• In Mora paper…Used database of 1.2 million• “catalogued 1.5 million”
• Much of the uncertainty revolves around number of insects… (and what other major group/s?)
Extrapolating actual number#1 (May)
•Assume all mammals have been identified.
•Found ratio of 1/3 Temperate to 2/3 Tropical mammals
•Assume all the Temperate insects have been identified (1 million)
•Then if this ratio is maintained we can extrapolate -----numbers of tropical insects should be .. ? 2 million (total insects should be?)
Extrapolating actual number#2 (May)https://canvas.sfu.ca/courses/.
10 8=100 million total
67/22,000
The guy that wrote your chapter!
Extrapolating actual number#3 (Gaston)
67/22,000 = 15,000/N
The guy that wrote your chapter!
Extrapolating actual number#4 (Erwin)
•Insecticidal fog
•Estimated number of species in a specific tree
•Then extrapolated given the number of tree species (a better known taxon)
•Argues for 30 million insects alone
2 million described +
May said add 2 million more for insectsMay said add 100 million based on sizeGaston said add 5-6 million more for insectsErwin said add 30 million more for insectsPimm a well respected ecologist said 100 million
(Some of these estimates are referred to in Table 1 of article for Friday…)
What organisms are NOT included in these estimates???
1. Why bother with the hopeless task of counting species? 2. Review the nested nature of taxonomy!
3. What did they do with the “1.2 million currently valid from several publicly accessible sources”? What do they mean temporal accumulation curves of different taxa? Why would they be interested in when we discover species over time?
4. What do the graphs in Figure 1A-F show?
What about graph 1G, what does it show?
5. What does Figure 2 show? What do they mean they are validating their approach?
6. What are at least two of the limitations of this approach that they describe?
7. What do you notice about Table 2? (FYI the Chromista are the non Protozoan Protists)
How do these numbers compare with the estimates we went over? From the table, what groups have we done a good job with in terms of finding/identifying species and which have we done a poor job?
7. What were the main points of the critics of the paper? (Zimmer article and Eisen’s blog)
There is a good analogy concerning a pyramid-did you notice?
Recommended