Lecture 23: Hawaii

Question 1

What is significant about the location of hawaii?

Answer 1

unconnected to any continents or existing fault lines (tectonic plate edges)

Question 2

How are islands typically formed?

Answer 2

In convergent plate boundaries, subduction zones cause magma upwelling and in oceans this creates islands (this can also happen at diverging boundaries)

Question 3

How were hawaiian islands formed?

Answer 3

The plate moves over a hotspot meaning an island is formed then the plate scooches over and another forms next to it

Question 4

How is an atoll formed?

Answer 4

As sediment erodes, it creates shallow sea shelves for coral growth –> Coral reef surrounding the island grows and terrestrial land erodes –> all that remains is the coral ring

Question 5

How did life travel to hawaii (3 ways)?

Answer 5

Ocean dispersal (ex: coconuts landed in the water and floated to hawaii)
aerial dispersal (ex: seeds and insects were carried by the wind)
Avian dispersal (ex: snails were brought over by birds)

Question 6

Why are so many founder species from asia?

Answer 6

Jet stream transports spores, seeds, insects, and flying mammals across the ocean

Question 7

What is the rain shadow effect?

Answer 7

Hot moist air comes off from the ocean and hits a mountain where it is forced upwards –> cold temps upwards cause rainfall on one side of the mountain and the dry air continues to the other side

Question 8

Why are islands prone to invaders?

Answer 8

Loss of defense: animals without predators dont need defense mechanism so invaders have an easy target

Question 9

Why do plants grow/increase in biomass at the intermediate substrate age?

Answer 9

At first, growth is slow, then it ramps up, but then once nutrient supply is exhausted, it declines.

Question 10

T or F: Volcanic activity is always destructive.

Answer 10

False! Destructive in short term but not in long term: provides new land area and minerals from plant growth and erosion brings minerals to marine environments