Geologic Time

1
Geologic Time
1st birds - 145
1st Reptiles - 338
1st Amphibians - 370
1st gnathostomes - 440
1st fishes 500 conodonts
2
Zoogeography
Continental Drift -Theory of Plate Tectonics
http//www.scotese.com/pangeanim.htm
3
Zoogeography
Continental Drift from 600 to 420, 6
continents drifted around, many of these land
masses were composed of parts of current day
fragments (Laurentia, Gondwana).
565 MYA 500 MYA - http//www.jamestown-ri.info/
avalonia.htm
About 400MYA Lauentia and Baltica collide forming
Laurasia About 300 MYA Laurasia collides with
Gondwana forming Pangea
4
Zoogeography
225 MYA - Pangea
200 MYA Laurasia begins to separate from
Gondwanaland
206-144 MYA (Jurassic) NA moves west, separates
from Europe (only connected in north)
144-65 MYA (Cretaceous) sea levels rise
flooding central NA
Gondwanaland breaks up Africa splits off India
breaks off SA and Australia still connected for
a while until they break off
Present day 3 MYA SA and NA reconnect, 10 MYA
India hits Asia, 40,000 YA - Bering land bridge
http//www.scotese.com/pangeanim.htm
5
Continental Drift -Theory of Plate
Tectonics Evidence fossils (similarity and
dissimilarity), geology, age of expanding sea
floor in Atlantic genetics of biota
6
Biogeographic regions (Wallace 1876)
Nearctic (holarctic) NA and some of Mexico
Palaearctic (Holarctic) Europe and Asia (North
of Himalayas)
Neotropical SA and Central America
Africa (Etheopian) African continent below the
Sahara Desert
Asian (Oriental) India, SE Asia, and Indonesia
Australia - depauperate
7
Annual migration of 19 Sooty shearwaters http//ne
ws.nationalgeographic.com/news/2006/08/060808-bird
-migration.html
Continental drift and the history of vertebrate
evolution over geologic time determine the
distribution of vertebrates (including fishes,
but not so much for birds)
8
Changes to the climate also affect current animal
distributions Glaciation
3 in last 100,000 years (Wisconsin
Glaciation) Glaciers reduce sea level bering
land bridge
Effect on fauna dependent on aquatic
fauna orientation/position of drainage
genetic evidence
Effects on Europe species richness relics endem
ics
9
Animal distributions
Geographic Range area in which an animal is
found
Endemic species is only found in a certain
region
Cosmopolitan species widespread species
Notropis photogenis
Disjunct population a population of a species
that is isolated from the main population of the
species
Barriers to dispersal Physical Mountains,
oceans Climatic Sahara, Biological
Placentals in NA
10
Animal distributions
Teminology Native a species indigenous to an
area
Introduced a species put into an area by humans
Naturalized an introduced species reproducing
on its own
Invasive a species (usually introduced) that is
expanding its range
Exotic reserved for introduced species that are
not native to the biogeographic region they have
been put in.