L7

Question 1

Darwin on the fossil record

Answer 1

• Rock record has to be incomplete
  • Despite having an incomplete and biased fossil record, we know this perspective was incorrect
  • In recent years there has been a concerted effort by palaeontologists to analyse the quality of the rock and fossil records

Question 2

7 Evolutionary patterns from the fossil record

Answer 2

1 Biodiversity
2 Morphological disparity
3 Origination patterns
4 Extinction patterns
5 Taxonomic duration
6 Rates of evolution
7 Fossils and biogeographic patterns

Question 3

Morphological disparity

Answer 3

• Can change across in time across groups
  
  • Modern area of palaeontology

Land form analysis
- Less disparity early on

Question 4

Origination patterns

Answer 4

• Always begin with a cladogram
  • Do species originate at the same rate constantly - if not why?

Question 5

Extinction patterns

Answer 5

• Do they cluster at certain times?
  • Little extinction events cluster
  • Other groups don’t follow mass extinction pattern

Question 6

Mass extinction

Answer 6

• There is a need to differentiate between background extinction, pulses of extinction (extinction events) and mass extinctions

Question 7

The Five big mass extinctions

Answer 7

End ordovician
Short glaciation event

End devonian
Pulses due to aquatic anoxia, related to spread of forests

End permian
Atmosphere pollution and heating due to emplacement of siberian LIP

End triassic
Emplacement of central atlantic LIP, low oxygen levels

KT (bolide impact)

Question 8

Why is it tricky to study mass extinction?

Answer 8

• Tricky to study mass extinction as need rock record in a variety of habitats, the signor lipps effect can muddy the waters

Mass extinctions vary in magnitude

Gould’s contingency

Recovery can be rapid (adaptive radiation into the created vacuum) or protracted (cf. Lazarus Taxa and Elvis Taxa and the Lilliput Effect)

Question 9

Gould’s contingency

Answer 9

What is affected varies due to the nature of the causal mechanism (but may be stochastic)

Question 10

Signor- lipps effect

Answer 10

• Mass extinctions vary in magnitude
  • What is affected varies due to the nature of the causal mechanism (but may be stochastic - gould’s contingency)
  • Recovery can be rapid (adaptive radiation into the created vacuum) or protracted

Question 11

Lazarus taxa

Answer 11

• Dissapear for while and come back
  • Seperated into small populations

Question 12

Elvis taxa

Answer 12

• Evolved independently to

Question 13

Lilliput effect

Answer 13

• Small taxa

Question 14

Taxonomic duration

Answer 14

• Chances of going extinct is independent to age

Question 15

Rates of evolution (morphological, genomic, taxic)

Answer 15

• Create phylogeny and plot against rock
  • Plot where characters occur
  • Do characters bunch up early on / randomly?

Question 16

Fossils and biogeographic patterns

Answer 16

• Time slice was a previous method
  • Rub out species name and plot location of occurrence
  • Natural groupings of locations
  • Can plot occurrences and work out spread over time

Question 17

What pattern of evolution did Darwin predict?

Answer 17

Phyletic gradualism

Question 18

Punctuated equilibrium

Answer 18

• Fossil record shows no change in some species for millions of years, then a new
  • Stasis
  • Most species spent most evolutionary history in morphologically identical stasis
  • Most species identical through time
  • Rapid speciation does occur

Question 19

Species sorting

Answer 19

• Fledgling species are more likely to survive if they are ecologically different from their parent species

Question 20

Species selection

Answer 20

• The differential rates of appearance and extinction of species within lineages

Question 21

Habitat tracking

Answer 21

• Ecological communities follow habitats as they move during environmental change

Question 22

The red queen

Answer 22

• Species compete and counter adapt

Question 23

Court jester

Answer 23

• Environmental factor against competition

Question 24

Evolution is a pattern of both…?

Answer 24

The red queen and court jester

Question 25

What are the three tiers of evolution?

Answer 25

Tier 1. Microevolutionary processes eg competition Tier 2. Punctuated events Tier 3. Mass extinctions

Question 26

Is macroevolution microevolution scaled up or something different?

Answer 26

Who knows

Question 27

What defines a bird?

Answer 27

- Feathers used in flight - Carpometacarpus - Unique foot structure - Pygostyle - Hollow bones with pneumatic foramen (air sacs) - Sternum and keel - Furcula (wish bone) - High EQ with advanced vision (3D plane)

Question 28

Any evidence of bird in the fossil record?

Answer 28

- Archaeopteryx - A bird with flight feathers and furcular - But note the teeth, tail, claws on the hand, gastralia (belly ribs) - primitive characters - Half bird / half reptile

Question 29

What does cladistic analysis have to say on the matter?

Answer 29

- Share the diagnostic characters of dinosauria - Feathered dinosaurs come out as a sister group to dinosaurs - Some birds discovered flight independently - Not active flyers but used occasionally for jumping etc - Later evolve for thermal regulation - Feathers and other characters that characterise birds (and enable flight) evolved in dinosaurs over an extended period of time - Macroevolution is a slow process of character acquisition

Question 30

Feathered dinosaurs come out as a sister group to ...?

Answer 30

Dinosaurs

Question 31

Macroevolution is a ...?

Answer 31

Slow process of character acquisition

Question 32

Two hypotheses for flight in Birds?

Answer 32

The arboreal or cursorial hypothesis

Question 33

Which of the two hypotheses are more likely to have led to flight?

Answer 33

Cursorial hypothesis