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Flashcards in Adaptive radiation Deck (35)
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1
Q

What does the difference in size and beak shape reflect?

A

Different foraging strategies - ecological niche.

2
Q

What was surprising about the birds darwin collected?

A

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

3
Q

What are the closest relatives to the finches?

A

The tanagers from South America.

4
Q

When do generalists compete well?

A

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

5
Q

When do specialists compete well?

A

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

6
Q

What are the three features of adaptive radiation?

A

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.

7
Q

Honeycreeper finches?

A

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

8
Q

What do honeycreeper finches evolve from?

A

Rosefinches.

9
Q

SIlversword alliance?

A

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

10
Q

Why are islands focused on within studies?

A

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.

11
Q

Kangaroo?

A

Product of adaptive radiation.

12
Q

What are colonization radiations?

A

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

13
Q

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

A

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

14
Q

Why do adaptive radiations arise?

A

Due to opportunities - little or no competition for resources.

15
Q

What is the creaceous-tertiary boundary?

A

When the dinosaurs and everything else went extinct.

16
Q

What was found in the K-T boundary clay?

A

Iridium.

17
Q

How does mass extinction have events similar to adaptive radiation?

A

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

18
Q

What happens to birds at the K-T boundary?

A

They disappear and never show up again.

19
Q

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

A

New kinds of birds appeared - massive radiation.

20
Q

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

A

Lizards and snakes,

21
Q

How have modern lizards formed?

A

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

22
Q

What is creative destruction?

A

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

23
Q

K-T extinction effects ?

A

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

24
Q

What are the 5 big mass extinctions?

A

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

25
Q

Cambrian explosion significance?

A

Biggest adaptive radiation of all time.

26
Q

What were the features of the Cambrian explosion?

A

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

27
Q

What drives radiations in the Cambrian explosion?

A

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

28
Q

How else can adaptive radiations occur?

A

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

29
Q

What is terrestriality?

A

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.

30
Q

What does the evolution of flight allow?

A

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

31
Q

What did evolution of flowers lead to?

A

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

32
Q

What is punctuated equilibrium?

A

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

33
Q

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?

A

They can all be seen as adaptive radiations.

34
Q

-summary- What are adaptive radiations?

A

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.

35
Q

-summary- When do adaptive radiations occur?

A

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