Transcript Geologic Processes, Climate Change and Evolution

Geologic Processes, Climate
Change and Evolution
Location of continents and oceanic basins influence
the earths climate, determining where plants and
animals can live.
The movement of continents has allowed species to
move, adapt to new environments and form new
species through natural selection. Continental
movement, earthquakes and volcanoes can isolate,
join together or destroy populations.
pANGAEA
In 1915, the German geologist and meteorologist Alfred Wegener
(1880-1930) first proposed the theory of continental drift, which
states that parts of the Earth's crust slowly drift atop a liquid core.
The fossil record supports and gives credence to the theories of
continental drift and plate tectonics. Wegener hypothesized that
there was an original, gigantic supercontinent 200 million years ago,
which he named Pangaea, meaning "All-earth". Pangaea was a
supercontinent
consisting of all of Earth's
land masses. It existed
from the Permian through
Jurassic. It began
breaking up during the
late Triassic period.
 Changing climates- species can’t adapt fast enough
 Asteroids colliding wit
h the earth
Changes in Ice Cover
How do speciation, extinction, and
human activities affect
biodiversity?
 Under certain circumstances, natural selection can
lead to an entirely new species.
 This process is called speciation and is when 2 species
arise from 1.
 A new species has formed when some members of the
population can no longer breed with other members to
produce fertile offspring.
 (refer to speciation webquest for details)
How Do New Species Evolve?
 Geographic isolation (allopatric)
 Migration, separation by a physical barrier, carried away
by wind or water
 Reproductive isolation- geographic separation
prevents reproduction, mutations in one population
occur, and a new species forms.
Geographic Isolation Can Lead to
Reproductive Isolation
Extinction is Forever
 Extinction
 Endemic species – species found in only one area
 Particularly vulnerable
 (Golden toad in Costa Rica is
extinct- 1989 lived in a
small area in the cloud rain
forest)
 Background extinction- normal rate of extinctions
 Mass extinction- a significant rise in extinction rates
where 25-95% of species may be wiped out.
 5 mass extinctions have occurred
 Mass extinctions give opportunity for the evolution of
new species to fill unoccupied niches or to create new
ones.
 Many believe we are headed toward the 6th mass
extinction.
 Background extinction- normal rate of extinctions
 Mass extinction- a significant rise in extinction rates
where 25-95% of species may be wiped out.
 5 mass extinctions have occurred
 Mass extinctions give opportunity for the evolution of
new species to fill unoccupied niches or to create new
ones.
 Many believe we are headed toward the 6th mass
extinction.
What Roles Do Species Play in Ecosystems?
 Ecological niche, niche
 Pattern of living
 Generalist species
 Broad niche
 Specialist species
 Narrow niche
Specialized Feeding Niches of Various Bird
Species in a Coastal Wetland
Niches Can Be Occupied by Native and
Nonnative Species
 Native species
 Nonnative species; invasive, alien, or exotic species
 May spread rapidly
 Do not have natural predators
 Compete with native species
 Not all are villains
Keystone, Foundation Species Determine Structure,
Function of Their Ecosystems
 Keystone species – important for the entire
community/ecosystem
 Pollinators- bees and bats
 Top predators – alligator, wolf, lion
 Ex: krill, sea star, gopher tortoise, sea otter, beaver
 Foundation species
 Create or enhance their habitats, which benefit others
 Ex: elephants, beavers
 Some species can be both a keystone and foundation
species
Most of what we know of Earth’s
life history comes from fossils
 Mineralized or petrified replicas of skeletons, bones,
teeth, shells, leaves and seeds
 Core samples from glacial ice
 The fossil record- an uneven and incomplete record
 Fossils found probably represent only 1% of all species
that have ever lived!
 Paleontologists study fossils.
Fig. 4-3, p. 81
 A more common time limit defines fossils as
being prehistoric thus; fossils preserve remains or
activities of ancient organisms older than 10,000
years
 The majority of fossils are found in sedimentary
rocks. Organisms become trapped within
sediment layers due to the action of water, wind
or gravity.
 Fossilization often occurs as a result of rapid
burial, usually by water-borne sediment, followed
by chemical alteration. Rapid burial and specific
chemical environments help to reduce
decomposition from bacteria and fungi.
 There are six ways that organisms can turn into fossils, including:





unaltered preservation (like insects or plant parts trapped in
amber, a hardened form of tree sap)
permineralization=petrification (in which rock-like minerals
seep in slowly and replace the original organic tissues with silica,
calcite or pyrite, forming a rock-like fossil - can preserve hard and
soft parts - most bone and wood fossils are permineralized)
replacement (An organism's hard parts dissolve and are replaced
by other minerals, like calcite, silica, pyrite, or iron)
carbonization=coalification (in which only the carbon remains
in the specimen - other elements, like hydrogen, oxygen, and
nitrogen are removed)
recrystallization (hard parts either revert to more stable
minerals or small crystals turn into larger crystals- mostly in
oceans)
authigenic preservation (molds and casts of organisms that
have been destroyed or dissolved).
“All we have yet discovered is but a
trifle in comparison with what lies hid
in the great treasury of nature.”
Antoine Van Leeuwenhoek