1. 98. Sections 3 & 4:
Biogeography – the study of where organisms live and their methods of dispersal to those places
The Earth’s biogeography has been affected by continental drift – the slow movement of land masses riding atop the hot, liquid core of the Earth.

2. 99. Changing Earth:
225 million years ago only one large land mass called Pangaea existed; over time the continents we know today separated and took up their present locations

3. 100. Dispersal – the movement of organisms from one place to another
Large organisms may be able to walk, swim or fly to new locations
Methods of dispersal for small organisms:
1) Wind – blows bacteria, fungi spores, seeds and tiny insects or spiders
2) Water – moves floating objects like coconuts, leaves or branches that serve as rafts for insects and small animals
3) Animals – eat seeds and carry them elsewhere
4) Humans travel all over the globe and may carry parasites, insect pests, rodents, etc.

4. 101. Limits to Dispersal
Three things can stop the spread of new species:
1) physical barriers – water, mountains and deserts are hard to cross
2) competition – if one species uses all of the resources, new species will be kept out of the area; especially true among plants
3) climate – each organism requires a certain climate

5. 102. Species Types:
Native Species – those organisms that evolved naturally in an area; raccoons are native to N. America
Endemic Species – native species that are different from those found anywhere else in the world; kangaroos are endemic to Australia (no other continent has them)
Invasive Species – organisms that have been transported to new locations where they create problems as they compete with native species

6. Let’s see some native species…
This link shows a unique museum that includes many species native to the Arizona desert:

7. Let’s see some endemic species…
These clips features species found only in the Galapagos Islands (off the coast of S. America):

8. Let’s look at some invasive species…
America faces a growing problem with thousands of organisms invading our country:

9. Do Not Copy Biomes – a group of ecosystems with similar climate & organisms (handout #103)
Six major land biomes:
1) Desert – very hot, dry climate; cacti are specially adapted for low rainfall
2) Grassland - not enough rain for large trees; mostly grass; kinds exist  a) prairie (hot summers & cold winters); central U.S. b) savanna (warm all year; some small trees); Africa
3) Deciduous Forest – hot summers; cold winters cause trees to shed their leaves and animals to hibernate; trees include maples, oaks, elms, etc. this is our biome
4) Rain Forests – plentiful rainfall kinds exista) Tropical Rain Forest (hot all year); near equator b) Temperate Rain Forest (cooler climate); Northwest U.S.
5) Boreal Forest (also called Taiga) – winters are long & very cold; trees are coniferous w/ needles to conserve water since snow has no chance to soak down into soil during cold months
6) Tundra – extremely cold & dry; permafrost is soil that stays frozen all year; mostly small plants; north of Arctic Circle

10. Major Land Biomes: Cold Hot Dry Wet Boreal Forest Prairie Grassland
TUNDRA
Boreal Forest
Prairie Grassland
Deciduous Forest
Temperate Rain Forest
Savanna Grassland
Desert
Tropical Rain Forest

11. 104. Miscellaneous Geographic Regions (some areas do not fit any biome description):
1) Mountain Ranges – the conditions of temperature and moisture change from the base of a mountain to the peak so that a single biome doesn’t apply;
2) Polar Regions – Most of Greenland (near North Pole) and all of Antarctica (South Pole) are covered by thick sheets of ice so there are no plants there

12. 105. Freshwater Biomes
1) Still water: holds less dissolved oxygen; inhabited by bass, sunfish, carp, catfish, etc a) ponds – small, shallow and warmer b) lakes – larger, deeper and colder
2) Moving water: holds more dissolved oxygen (due to mixing of air with the water); inhabited by trout, salmon, etc a) streams – small, swift, cold b) rivers – larger, slower, warmer

13. Do Not Copy Marine Biomes (handout #106):
1) Estuary – where a river meets the ocean; lots of nutrients and sediments are dumped here creating a habitat suitable for many organisms to live
2) Intertidal Zone – the shallows between the high tide mark and the low tide mark; only covered by water some of the time
3) Neritic Zone – shallow water from the low tide mark out to the edge of the continental shelf (where deep water begins)
4) Photic Zone – water near the surface extending down only a few hundred meters; this is where light is able to penetrate; all the producers (algae and plankton) here & the most animal life
5) Benthic Zone – all along the ocean floor from shallow water to the deepest parts; can be total darkness

14. Photic Zone (Just Beneath the Surface)
High Low Shelf
Tide Tide Edge

15. 107. Succession: changes in the environment over time
Two types: 1) Primary Succession- These changes occur in an area that starts with no soil (just bare rock) and no organisms; example could be a volcanic island where eventually soil forms and organisms move in.
2) Secondary Succession – These changes occur after a disturbance in an ecosystem wipes out all the organisms, but soil remains; examples could be a forest fire or a hurricane followed by slow recovery during which plants and animals return.

16. Animation of Primary Succession:

17. Explanation of Secondary Succession:
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18. Image Credits:
Pangaea: m=isch&prmd=imvnsb&tbnid=5hrJFjFO1pvJ2M:&imgrefurl= tline/activezone/slides/pangea- slide.html&docid=rqFgtIUIIFxqQM&imgurl= es/pangea_lrg.gif&w=530&h=661&ei=DV0dT9KnIqPz0gHoh9ylCg&zoom=1&iact=rc&dur=498 &sig= &page=1&tbnh=143&tbnw=115&start=0&ndsp=11&ved=1t:42 9,r:2,s:0&tx=69&ty=64
Continental Drift:
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19. Image Credits: Galapagos:
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