PLATE TECTONICSMrs. Page

ESS 2015-2016

Influence on Evolution & Biodiversity

ASSESSMENT STATEMENT:Explain how plate activity has influenced evolution and biodiversity. Speciation through physical barriers Consequences of isolation for evolution Role of activity in generating new and diverse habitats (increasing biodiversity)

EARTH’S INTERIOR• Earth’s Crust sits on top of a convecting mantle

• The upper mantle (asthenosphere) is moving do to convection currents.

• This movement of the mantle causes Earth’s crust to move over time resulting in many of the landforms and geographic events that occur on Earth.

THEORY OF PLATE TECTONICS

Earth’s crust is broken into large pieces called plates

Plates move over time creating many landforms & geologic events such as earthquakes and volcanoes

EARTH THROUGH HISTORY Because Earth’s plates are moving, the

continents have not always been in their present location.

Pangaea – large supercontinent

As continents move apart – physical isolation may occur

Geologic events – volcanoes & earthquakes can bring about loss of habitat and potential loss of species

HISTORY OF MASS EXTINCTIONS Throughout history

there has been several periods of mass extinctions

One theory: Possible large volcanic eruptions blocking sunlight & destroying habitats.

TYPES OF PLATE MOVEMENTSConvergent: pushed togetherDivergent: moving apartTransform: sliding pastWhat happens at plate boundaries can be constructive: building new land (ie: habitats) or destructive; destroying land

CONVERGENT BOUNDARIES (COLLIDING)3 Scenarios:

2 Continents Collide = folded mountains

Could lead to isolation – mountain range separates a population

Creates new habitatBoth constructive (building mountain) and destructive (one plate subducting)

Himalayas

Rocky Mountains

CONVERGENT BOUNDARIES (COLLIDING) 2 Oceanic Plates

Collide More dense plate subducts

Deep sea trench Oceanic Islands New Land formation = new habitat

Aleutian Island Arc: Possibility of future land bridge?? Affect on evolution & biodiversity?

CONVERGENT BOUNDARIES (COLLIDING)1 Continental & 1

Oceanic Plate Collide Oceanic trench off coastline (oceanic plate subducts)

Coastal Volcanic Mountain Range

Cascade Mountain Range – west coast USA Pictured: Mt. St. Helens

Potential mass extinction caused by large volcanic eruptions

DIVERGENT BOUNDARIES (MOVE APART)

Oceanic-oceanicSea floor spreading

Mid Ocean Ridge

DIVERGENT BOUNDARIES (MOVE APART)

Continental-continental

Rift ValleyGeographic Isolation?

African Rift Valley

TRANSFORM BOUNDARIESPlates slide past with friction

EARTHQUAKE ZONES

APPLYExplain how plate tectonics has influenced evolution and biodiversity. Give specific examples.