2.5 natural disruptions to ecosystems

natural disturbances

a natural event that disrupts the structure and or function of an ecosystem

ex. tornado, hurricanes, asteroids, forest fires, droughts

diff types of natural disturbances

periodic, episodic, random

periodic

occurs with regular frequency

ex. dry/wet seasons

episodic

occasional events with irregular frequency

ex. droughts, hurricanes, fires

random

no regular frequency

ex. volcanoes, earthquakes, & asteroids

these are more substantial

natural climate change

earth’s climate has varied over geologic time for numerous reasons

ex. slight changes in earth’s orbit & tilt causes mini ice ages & warmer periods as earth shifts slightly closer/further to/from the sun

what does distance from the sun mean?

geological enters mini ice ages/warming cycles

malankuvich cycle

the malakuvich cycle is the fluctuation, the wobbling, and eccentricity. so our orbit isn’t perfectly circular around the sun, so there’s periods here we are further away (ice age) and where we’re closer (warming period).

global mass extinctions

there were 5 global mass extinctions. 5 global mass extinction events have occurred since the evolution of complex life roughly 500 million years ago.

• the mammals were able to take the niches that the dinosaurs occupied and thrive/diversify/adaptive radiation to be successful

plate tectonics

continental shift, forming & reforming continents over & over again. this affects climate. dry places aren't close to the coast, and coastal areas are able to moderate temp and redistribute precipitation.

• as continents shift, organisms have to adapt to the changing conditions. the surface area increased and allows for our climate to be more moderate.

what are ice ages followed by?

warming temp collisions, can lead to new species and extinction

changes in the last 1800s:

we can travel around the northern portion of the world in summer months

melting ice in greenland

largest island, 80% of glaciers, 10% of word’s freshwater, 1996-2007: net loss of ice doubled, effect on sea level

env change =?

habitat disruption

major env disturbances result in?

widespread habitat changes/loss

ex. rising sea levels floods coastal and estuary habitats

migration

wildlife may migrate to new habitats as a result of natural disruptions

ex. wildebeests migrating to follow rain patterns of African savanna

what happens if organisms migrate to a habitat that don’t support them

there will be a redistribution of organisms

• bird migration & breeding shifting earlier as inspect hatching shifts earlier w warming climate

what happens to ocean species as water temp increases in term of migration

they move further north