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Flashback to Ch3. List the 4 types of keystone species

modifier of physical environment
continuous food providers


Where are the two most diverse ecosystems one earth (that the book picked)

tropical rain forest
coral reefs


What two variation styles are theorized to result in diversity patterns on earth?

variation in climate/environment

variation in topography, geological age, and habitat size.


Describe the rain forests

occupy 7% of land area

contain over half of the world's species
based mainly on samping of arthropods
reasonable estimates range from 5-10 million species
maybe up to 30 million

40% of plants are found in rainforests (275k sp total)
30% of birds are found here. (of about 2600 species)


What physical aspect of the rainforest lends itself to diversity?

the layering of foliage and communities within the canopy


Trends in rainforest availability

around the equator is the most dense, but in general we just have been killing it.


Describe coral reefs

marine equivalent to tropical rain forests in species richness and complexity

high productivity
-sunlight penetrates deeply through the clear water


How do cruise boats and resorts hurt coral reefs?

pollution. Clear water is essential to coral reef functioning/productivity


Facts about the great barrier reef

349000 square km (0.1% of ocean surface)
400 species of coral
1500 species of fishes (8% of world's fish species)
4000 species of mollusks
6 spcies of turtles


What are the differences between tropical rain forests and coral reefs

very few reef species have narrow distributions like rain forests

widely dispersed during juvenile phase.
only isolated islands like Hawaii have endemic species

Most biodiversity is found ONLY in the oceans.
(Diversity is spread over broad range of phyla and classes)


Diversity is spread over broad range of phyla and classes. Give some specific stats.

32 of 34 extant animal phyla are found in marine systems

13 of these exist only in marine environment (not fresh water or land)

1 phylum is found exclusively in terrestrial environments.
0 phyla are found exclusively in freshwater environments.


Patterns of diversity that vary in climate and environment show that species richness increases with what 3 factors mainly?

3 main factors:
-decreasing elevation (mts vs valleys)
-increasing solar radiation (equator)
-increasing precipitation


What factors cause species diversity to increase with variation in topography, geological age, and habitat size? Why?

-complexity of topography (diff habitat types)

-greater geological age
--coral sp. richness is greater in indian and west pacific ocean vs Atlantic which is younger

-habitat size

Why: It allows genetic isolation, local adaptation, and speciation.


What correlations exist among types of organisms in distribution of species richness?

The amount of diversity among these groups is correlated.

Amphibians, birds, mammals, and plants in South America:
-most in western amazon
-secondary concentration in highlands of NE South America.

Birds, amphibians, and mammals in africa.


Hot spots

areas of species diversity that are very important to conserve.


Why are there so many species in the tropics? (5 reasons)

receive more solar energy

have had longer periods of stability

have warm temperatures and high humidities

more predictable environments

larger geographical areas


What groups of organisms have more species diversity toward the tropics?

almost all groups.

birds, trees, mammals, mollusks

exceptions: marine algae (20-40 degrees latitude) and small groups like bees, penguins, salamanders, waterfowl

Marine species also increase toward tropics
-great barrier reef northern end has more sp than southern end
-tunicates (sea squirts) have 6x the sp diversity toward tropics


How many tree species are in a hectare of the amazon compared to a US/European forest?

>>300 spcs, compared to less than 30 in american termpate forest

"maybe not on test"


More solar energy in the tropics results in..

more abundant rainfall

higher rate of productivity

greater resource base can support wider range of species


why have the tropics had longer periods of stability

no glaciation
allowed uninterrupted evolution and speciation
has allowed greater evolutionary specialization and local adaptations in tropical areas


How do warm temps and high humidity help species diversity in the tropics

favorable conditions for growth and survival for most species

do not need to evolve mechanisms to cope with cold/freezing conditions

entire communities can develop in tree canopies


How do predictable environments help with species diversity in the tropics?

species interactions are more intense

leading to greater competition among species

leads to more speciation via niche specialization


How does a large geographic area help develop sp. diversity in the tropics?

leading to greater rates of sp. and lower rates of extinction

tropicsl areas north and south of equator are next to one another

temparate areas are divided by tropics

therefore, more overall connected space.


How many sp. worldwide?

about 1.5 million have been described

300,000 fossil species
mainly insects.

at least 2-3x remain undescribed
(estimated 5-10 million total)

20k sp discovered each year.
(1-2% increase per year for insects, spiders, mites, nematodes, fungi)


Name a few recently discovered communities

tropical tree canopies

earth's crust (bacterial communities 2.8 km deep, 1000 million cells/g rock)

interior of leaves of tropical trees
-1000s of sp of undescribed fungi
-symbioses: exclusion of harmful bacteria/fungi for carbs

deep sea floor
-almost entirely unexplored; unique geothermal vents; deep sediments

human body
-10 mill bacterial cells/cube cm
-182 species on arms of 6 people
-expect similar levels of microbial abundance on other animals


How do we collect/count species?

requires large institutions
team of scientsts

-we collect, sort. classify, and describe them.
(lots of beetles collected in Indonesia, identified about 3000 new species with this one adventure of 1million beetle collection)

ex. flora of N Am project; missouri botanical garden

ex. Flora Malesiana; Netherlands


What is a way to estimate the number of species?

Extrapolation of ratios of organisms

ex. insects in the rainforest
fungi in britain


Recently discovered underrepresented species

rare species like lithophragma maxima

recently evolved on Sam Clemente Island


What is a living fossil?

rare species
-Wollemi pine: genus thought to be extinct for 60 mya
found in a gorge in Wollemi National Park, Australia.
-40 Individuals alive.

-thought to be extinct 65 mya
-possible ancestor of first land vertebrate
-population of 200 found in underwater caves near Grand Comoro Island


Inconspicuous species

insects, fungi

viruses, bacteria, protists, unicellular algae

underdescribed areas (tropics)