Animal evolution and invertebrate diversity

Question 1

Two Approaches to Phylogeny:

Answer 1

1. Traditional:
2. Modern:

Question 2

Traditional

Answer 2

Traditional reconstructions are based on key aspects of body architecture and development
* Starts with Linneaus (1700s) and his binomial taxonomy
* Taxonomy is not phylogeny, and does not imply evolutionary
relationships; taxonomy is simply classification.
* Traditional phylogeny classifies together organisms and
phyla that share fundamental aspects of anatomy, body plan, and (later) embryonic development.

Question 3

Moderm

Answer 3

New reconstructions employ molecular comparisons and modern analytical tools (cladistics)
* Focuses on similarities/differences in ribosomal RNA sequences, mitochondrial DNA sequences, and/or other molecular evidence (such as genes controlling body plan- the homeobox, or hox, genes)
* Raises questions about basal animals and origin of animals * Establishes two major clades of protostomes- Protostomia
subdivided into:
* Lophotrochozoa (e.g., Bryozoa, Mollusca, Annelida) and * Ecdysozoa- Nematoda (roundworms), Arthropoda

Question 4

Conclusions of sponges evolution

Answer 4

➢ Ctenophores are the sister group to all other animals&raquo_space; ctenophores (not sponges) are the most basal group of animals.
➢ Neural components are similar in sponges and ctenophores; sponges have the “genetic machinery” for a nervous system, but have lost these cell types&raquo_space; sponges are degenerate (not basal).

Question 5

The first animal to probably appear on earth was

Answer 5

The humble sea sponge

Question 6

Sponges (porifera) are sister-group to all other………

Answer 6

multicellular animals

Question 7

previous findings of tress with………… were due to artifacts

Answer 7

Ctenophora sister

Question 8

Analyses of multigene datasets should employ…….

Answer 8

site-heterogenous evolutionary models

Question 9

Partioned phylogenomics does not support

Answer 9

comb jellies as sister to other animals at the supermatrix or partion specific level