L4: Taxonomy and phylogeny Flashcards Preview

APS 269 Palaeobiology > L4: Taxonomy and phylogeny > Flashcards

Flashcards in L4: Taxonomy and phylogeny Deck (36)
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1
Q

What is taxonomy?

A

The classificationof a species.

2
Q

What is phylogeny?

A

The study of evolutionary history and relationships among individuals or groups of individuals

3
Q

What is the general definition of what a species is?

A

Species reproduce to create viable offspring. Species may transform into another new species.

4
Q

What form does evolution take?

A

bifurcated tree

5
Q

What are the problems faced with phylogenetic analysis of the past?

A

Too much consideration of the presence and absence of characters
The lines of descent assumed we could identify ancestors by way of one species giving rise to another
Too much reliance on stratigraphic distribution of fossils

6
Q

What is the cladistics revolution?

A

Scientists working on insects realised the techniques used to determine evolution were flawed - from this, they generated cladistics

7
Q

What is cladistics?

A

an approach to biological classification in which organisms are categorized in groups based on the most recent common ancestor

8
Q

What is the parsimony method for analysing character distribution?

A

Look at the simplest way to acquire characters

9
Q

What is the bayesian method for analysing character distribution?

A

Uses a likelihood function

10
Q

What are synapomorphies?

A

Characteristics present in ancestral species and shared exclusively by evolutionary descendants

11
Q

What are synplesiomorphies?

A

Ancestral traits shared by two or more taxa, but also with other taxa in early line

12
Q

What are autopomorphies?

A

Distinct features, they are derived traits that are unique to a given taxa

13
Q

What is homology?

A

A character shared by a set of species but not present in their common ancestor

14
Q

What are the 5 steps for constructing a cladogram?

A
Create a character matrix
Analyse character distribution 
Identify where characters arise - homologus or analogous 
Establish sister group relationships 
Illustrate using a cladogram
15
Q

What is a monophyletic group?

A

a group of organisms that are classified in the same taxon and share a most common recent ancestor

16
Q

What is a paraphyletic group?

A

descended from a common evolutionary ancestor or ancestral group, but not including all the descendant groups

17
Q

What is a polyphyletic group?

A

derived from more than one common evolutionary ancestor or ancestral group and therefore not suitable for placing in the same taxon

18
Q

What is the crown group?

A

Includes all living animals

19
Q

What is the stem group?

A

No living representatives

20
Q

What is the total group?

A

Everything from the common ancestors ,alive members and fossils

21
Q

What are the tetrapods?

A

A monophyletic group of vertebrates primitively bearing four limbs

22
Q

From what did tetrapods evolve?

A

From a fish species that crawled out of the water at the end Devonian, Evolved only once

23
Q

What are the four classes of tetrapods?

A

Amphibia
Reptilia
Aves
Mammalia

24
Q

What two groups do the tetrapods divide into?

A

The Anamniotes and the amniotes

25
Q

What are the anamniotes?

A

A whole host of extinct non amniotes and lissamphibia, which are the modern amphibians

26
Q

What are the amniotes?

A

Possess a membrane like amnion around the foetus, either retaining it in the womb or laying an egg

27
Q

What is the role of the amnion membrane?

A

Retains the moisture and allows the embryo to be continuously bathed in liquid

28
Q

What are the two lineages of the amniote tetrapods?

A

Synapsids and Reptilia

29
Q

What are the synapsids

A

Have a single temporal fenestra behind each eye. Made up of all mammals and some extinct early reptiles

30
Q

When did the synapsids diverge?

A

Between 310 and 320 MA

31
Q

What are the two important clades within reptile?

A

Anapsids and Diapsids

32
Q

What are the anapsids?

A

Skull roof is fully roofed, no wholes in the temporal region. Consists of Chelonia

33
Q

What are the diapsids?

A

Have two temporal openings in the skull roof as well as temporal fenestra

34
Q

What are the two major clades of the diapsids?

A

Lepidosauromorphs and Archosauromorphs

35
Q

What animals are in Lepidosauromorpha?

A

Lizards, snakes tuatara etc

36
Q

What clades lead from the archosoromorphs to the dinosaurs?

A

Archosauria, Ornithodia, Dinosauria