Adaptive radiation

Question 1

What does the difference in size and beak shape reflect?

Answer 1

Different foraging strategies - ecological niche.

Question 2

What was surprising about the birds darwin collected?

Answer 2

He thought they were all different species, but they were from the same lineage.

Question 3

What are the closest relatives to the finches?

Answer 3

The tanagers from South America.

Question 4

When do generalists compete well?

Answer 4

If resources are highly unpredictable year to year or season to season as it can rapidly shift to what is available.

Question 5

When do specialists compete well?

Answer 5

When resources are stable year-to-ear and season to season.

Question 6

What are the three features of adaptive radiation?

Answer 6

High diversity, wide range of niches occupied (diets, feeding adaptations, behaviours, body sizes etc) and occurs over a geologically short period - diversification of organisms into filling different ecological niches.

Question 7

Honeycreeper finches?

Answer 7

SImilar to darwin finches but are more specialised for their lifestyles and more diverse.

Question 8

What do honeycreeper finches evolve from?

Answer 8

Rosefinches.

Question 9

SIlversword alliance?

Answer 9

Adaptive radiation of 50 species of plant in the Hawaiian islands. Grow everywhere - arid volcano craters to rainforest bogs.

Question 10

Why are islands focused on within studies?

Answer 10

THey behave like continents but on a smaller scale and are easier to study. They show the same evolutionary processes but on a smaller scale - models.

Question 11

Kangaroo?

Answer 11

Product of adaptive radiation.

Question 12

What are colonization radiations?

Answer 12

Following a colonization of a vacant habitat, species can rapidly occupy empty niches.

Question 13

What is strange about groups of organisms that have successful adaptive radiations?

Answer 13

They are not successful in the place they come from - niches already filled.

Question 14

Why do adaptive radiations arise?

Answer 14

Due to opportunities - little or no competition for resources.

Question 15

What is the creaceous-tertiary boundary?

Answer 15

When the dinosaurs and everything else went extinct.

Question 16

What was found in the K-T boundary clay?

Answer 16

Iridium.

Question 17

How does mass extinction have events similar to adaptive radiation?

Answer 17

Allows survivors to colonise disturbed environments and radiate. Similar to the galapagos but play out on the scale of continents.

Question 18

What happens to birds at the K-T boundary?

Answer 18

They disappear and never show up again.

Question 19

What happened to birds 10 million years after the K-T extinction?

Answer 19

New kinds of birds appeared - massive radiation.

Question 20

What other organisms went extinct at the K-T boundary?

Answer 20

Lizards and snakes,

Question 21

How have modern lizards formed?

Answer 21

Diversification to take advantage of niches left vacant by extinction of cretaceous lizards.

Question 22

What is creative destruction?

Answer 22

Rise and spread of new tech. is linked to the destruction of old ones - economy is constantly renewing and destroying itself.

Question 23

K-T extinction effects ?

Answer 23

75% of species eliminated but diversity rebounds rapidly and soon surpasses cretaceous diversity levels.

Question 24

What are the 5 big mass extinctions?

Answer 24

Cretaceous-tertiary, triassic-jurassic, permian-jurassic, permian-triassic, late devonian and cambrian ordivician.

Question 25

Cambrian explosion significance?

Answer 25

Biggest adaptive radiation of all time.

Question 26

What were the features of the Cambrian explosion?

Answer 26

Dramatic increase in diversity, new kinds of organisms, happened very quickly - modern annelids, arthropods, chordates, mollusks.

Question 27

What drives radiations in the Cambrian explosion?

Answer 27

Destruction of the old order - creative destruction - origins of new, complex, multicellular life may be in the extinction of the old.

Question 28

How else can adaptive radiations occur?

Answer 28

If organisms hit upon entirely novel ways of making a living - they don’t wait for an opportunity, they create it.

Question 29

What is terrestriality?

Answer 29

The evolution of life on land - migration of plants/arthropods etc. onto land creates a new ecosystem - one that doesn’t directly compete with the old, marine ecosystem.

Question 30

What does the evolution of flight allow?

Answer 30

Opens up new niches - airborne predators, herbivores, fish-eaters etc. Animals can exploit low-density resources or seasonal resources.

Question 31

What did evolution of flowers lead to?

Answer 31

A massive adaptive radiation of flowering plants in the Mid-Cretaceous.

Question 32

What is punctuated equilibrium?

Answer 32

The idea that evolution occurs in fits and starts - bursts of creativity followed by periods where there are little changes.

Question 33

What do the Cambrian explosion, the rise of the mammals and the evolution of flight and success of Darwin;s finches all have in common?

Answer 33

They can all be seen as adaptive radiations.

Question 34

-summary- What are adaptive radiations?

Answer 34

Evolutionary bursts characterized by an increase in diversity, an increase in morphology and a range of niches occupied. They occur over a geologically short period of time.

Question 35

-summary- When do adaptive radiations occur?

Answer 35

When groups exploit previously unavailable niches by colonizing a new environment, occupying niches left vacant by extinction, evolving new adaptations.