PALAEOBIODIVERSITY

Question 1

What is palaeobiodiversity?

Answer 1

• Biodiversity from the past
• The world have been biodiverse throughout time

Question 2

How do se measure biodiversity?

Answer 2

Look at extant organims using the taxic approach

1. Examine rate of discovery curves
2. Extrapolate from intensive local sampling

Question 3

Why is it hard to estimate past biodiversity?

Answer 3

• Vagrancies in the fossil record
• Soft bodied organims won’t be preserved etc

Question 4

Why is it difficult to interpret biodiversity from the fossil record?

Answer 4

• Ontogentic stages: Carapace shedding (is it different stages or different species?)
• Sexual dimorphism: Amonites (male and female first thought to be sepereate species)
• Diseased individuals
• Ecophenotypes: Different morphology in different niches

Question 5

Are Linnean hierarchies equivalent for different groups of organisms?

Answer 5

How accurate are the families
E.g. is a family of ammonites the same as a family of dinos?

Question 6

Not all species are conserved

Answer 6

Count number of genera or families to get a more accurate idea

Question 7

Estimate the sum total of species that have ever existed

Answer 7

• Based on average species durations and various bifurcating models of evolution. This suggests that extant species represent 2-4% of those that have ever lived.
• E.g. 250,000 fossil marine animals described; 200,000 extant marine animals described; allowing for non-preservable soft-bodied animals this suggest 25-75 million past species (only 2-4% of fossil marine animals described).

Question 8

Who looked at biodiversity patterns?

Answer 8

• Sepkoski curve
• Improved by Alroy using palaeo-database (computer database: PDB)

Question 9

Examples of biodiversity patterns?

Answer 9

• Marine inverts: Massive rise in the cambrian, drops during extinction events then continues to track up.
• Plants: Changes in reproductive strategies e.g. change to flowering plants etc
• Tetrapods: Move out of water, continue to diversify

Question 10

Theoretical consideration of biodiversity increase

Answer 10

• Linear model
• Exponential curve
• Logistic curve

Question 11

why is life is more diverse on land than the oceans

Answer 11

• Mainly due to insects & soil microbes
• Oceans are relatively steady environments
• Many more habitat types on the land than the oceans
• 95% of fossils described are marine

Question 12

Pull of the recent

Answer 12

• Rock closer to the present is less likely to be destroyed
• Measure of biodiversity gets better the closer we get to the present

Question 13

Equilibrium models

Answer 13

• Biodiversity ceiling due to diversity damping factors or limiting/equilibrium factors
• Competitive exclusion, carrying capacity etc
• Expansion models (no biodiversity ceiling)

Question 14

Fastovsky et al 2004

Answer 14

• Conclusion: Dinosaurs continued to diversify until their extinction (exponential)
• Dinosaurs kept evolving new strategies

Question 15

Wang and Dodson 2006

Answer 15

• Predicted that dinosaur diversification was slowing down by the end of cretaceous
• Took into account rock volume

Question 16

Lloyd et al 2008

Answer 16

• Cladistic study
• Worked out ghost lineages
• Predicted the pattern seen is due to sampling bias
• Concluded that there was no decline at the end of the cretaceous

Question 17

Barret et al 2010

Answer 17

• Focused on 3 clades
• Also looked at volume of rock
• Massive rock megabias
• Concluded there was a decline in dinosaurs at the end of the cretaceous