Smith, 2003 (Patchy fossil record)

Question 1

Until recently, the favoured method of estimating species … through time has been nothing more complex than…

Answer 1

counting the fossils recorded from each time interval, compiling taxonomic and stratigraphic data

Question 2

However, this simple approach is only valid if each time interval…

Answer 2

has been sampled to the same extent and is the same length of time.

Question 3

A study of fossil marine … and fossil localities in … … covering the past … million years showed that fossil sampling is very uneven (far from uniform). It found that sampling effort into rocks from certain time periods correlates with the amount of rock from that time period available at the surface, which is itself very uneven.

Answer 3

molluscs, New Zealand, 60

Question 4

The more thoroughly a rock unit is sampled,….

Answer 4

the more specimens are found, which leads to a higher recorded diversity.

Question 5

So if only a small amount of rock is present at outcrop, then the total … recorded is likely to be much … than if a large area of outcrop is available for sampling.

Answer 5

diversity, lower

Question 6

… is a statistical technique that uses subsampling to reduce populations to the same size and can be used to remove such ….

Answer 6

rarefaction, bias

Question 7

Initial large-scale studies using this approach suggest that global … pattens may indeed be substantially … by unequal ….

Answer 7

biodiversity, biased, sampling

though rarefaction requires more data than are generally available currently

Question 8

Hence, more indirect ways of estimating sampling levels are required. Estimates of how extensively a time interval has been sampled have been based on the number of named … …. The more geological formations that are recorded in a time interval, the greater the range of environments that exist to be sampled, and, presumably, the greater the species diversity.

Answer 8

Geological formations

this holds for the USA but not New Zealand
- may be due to stability of tectonic activity - much more active in NZ

Question 9

Sampling intensity has also been correlated with the area of rock available at outcrop for collecting: the larger the area at outcrop , the greater the opportunity for collecting and the greater the overall diversity. This correlation is strong for the …-… trend but not …-… changes.

Answer 9

long-term, short-term

Question 10

Rock … … is the more reliable predictor of sampling bias in the fossil record

Answer 10

outcrop area

Question 11

Additional complications: not just amount of outcrop available to sample that affects taxonomic diversity but also the…

Answer 11

range of past environments that those deposits preserve

Question 12

The NZ molluscan biodiversity curve is dominated by taxa that lived on the … …, with only relatively low-diversity mollusc faunas from the … ….

Answer 12

continental shelf, deeper ocean

Question 13

There are many reasons why this may be, one being how …-… … cab create a switch from predominantly shallow to deep marine deposits, and that this sampling bias may be the primary reason for the drop in species diversity seen at such times

Answer 13

sea-level rise

Question 14

… setting is an important factor in determining how rock bias and sampled diversity are related

Answer 14

tectonic

Question 15

A correlation between rock area and species diversity does not necessarily imply … and …. Both biodiversity and rock outcrop area could be driven by the same factor

Answer 15

cause, effect