Lecture 7 - evolutionary patterns from the fossil record

Question 1

what are the 2 important things we get from fossils?

Answer 1

1. snapshot of organisms that lived in the past and the environment they lived in - view of past life
2. put together the snapshots and see how evolution has occurred through time - mechanisms of evolution

Question 2

what is phyletic gradualism?

Answer 2

successive organisms through random mutation develop slight differences in variation: natural selection acts on that = survival of the fittest

Question 3

what are the 7 evolutionary patterns from the fossil record?

Answer 3

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

Question 4

what is morphological disparity?

Answer 4

the measurement of morphological diversity

Question 5

what are the big 5 mass extinctions?

Answer 5

1. end ordovician - short glaciation event
2. end Devonian - pulses due to aquatic anoxia] - 90% marine organisms extinct
3. end permian - atmosphere pollution and heating due tp emplacement of siberian traps LIP)
4. end triassic - ditto but due to emplacement of the central atlantic LIP)
5. KT - wiped out dinosaurs

Question 6

what is the signor lipps effect?

Answer 6

since the fossil record of organisms is never complete, neither the first nor last organism in a given taxon will be recorded as a fossil

Question 7

What is taxonomic duration?

Answer 7

survivorship curves; look at cohorts of taxa and see with time, how many survive

Question 8

what is punctuated equilibrium?

Answer 8

long periods of stasis and short periods of rapid speciation

Question 9

what is the red queen?

Answer 9

an evolutionary hypothesis which proposes that organisms must constantly adapt, evolve, and proliferate to survive while pitted against ever-evolving opposing organisms in an ever-changing environment
*biotic interactions e.g. competition drive evolution

Question 10

what is the court jester?

Answer 10

hypothesis that the environment is more important than biotic interactions to drive evolution

e. g. flip from greenhouse world to an ice house world
- occurs in a wider paleogeographic setting
- occurs at shorter periods of time

Question 11

what is species sorting?

Answer 11

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

Question 12

what is species selection?

Answer 12

the different rates of appearance and extinction of species within lineages

Question 13

what is habitat tracking?

Answer 13

ecological communities follow habitats as they move during environmental change

Question 14

what is the evolution hierarchy?

Answer 14

1. first tier - microevolution processes e.g. competition
2. second tier - punctuated events - trends with lineages over geological time
3. third tier - mass extinctions

Question 15

Key characteristics of birds:

Answer 15

• feathers
• structure of the hand is reduced
• foot is a clasping foot rather than a walking one
• tail lost to form a pygostyle - feathers attach
• bones hollow and light
• keele - allows large chest muscles for flight

Question 16

Archeoptryx

Answer 16

first bird - mid jurassic

had teeth, claws, tail but hollow bones and feathers