Penn BIO 417 – Why are pollutants particularly dangerous

12 Jun Penn BIO 417 – Why are pollutants particularly dangerous

Question
Short Answer Questions

Why are pollutants particularly dangerous to aquatic/marine life? (again, this could also go in the short essay section)

What is the difference between a tiny crustacean (copepod) moving through water versus a large animal such as a fish or human?

There are several types of cells found in sponges. In the space below, name and describe the function of four (4) of these cell types.

What limits the size of sponges with asconoid or syconoid morphologies? Explain.

List 3 examples of “skeletons” and indicate how they are made and what they are made off. (Not all skeletal structures are “rigid”, explain why)

What adaptations do cnidarians have for capturing prey?

How are arthropod muscles different than vertebrate muscles?

What are the four stages of Arthropod growth (MOLTING)? What does the animal do during these stages? What can trigger molting? Why is the trigger usually different in marine vs freshwater (aquatic) animals (Arthropods)? With “time” on the x-axis, graph on the the y-axes) the increase in 1) size and 2) biomass for a typical Arthropod.

What is significance to insect populations whose larval stage differs significantly from their adult stage? (this requires some thought!)

Tagmatization pertains to the regionalization of segments through specialization. Identify three major groups of Arthropod that exhibit broad differences in tagmatization. Explain.

What evidence indicates that hexapods are derived from crustaceans and likely from lineages that are common to freshwater environments?

Why do Arthropods lack external functional cilia?

How are the eyes of spiders different from the eyes of crustaceans and Insects?

EVOLUTIONARY RELATIONSHIPS:

Evolutionary reconstruction. In this example, tach numbered hash mark corresponds to a trait that unifies all the organisms corresponding to the branches drawn after the mark. These traits therefore distinguish each group, or groups, from all other animals and often dictate their biological success.

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example questions:

What is the trait (or traits) designated by #1 that unifies all of the Mandibulata?

Circle those groups that comprise the Acracnida and indicate a trait that unifies this animal clade.

What internal structures independently evolved in Hexapods and Myriapods?

Interpret hypothetical data

You are given the job to determine the evolutionary relationships among an important and endangered group of coral reef snail. 5 species and an out-group are presented to you (see below).

.jpg” alt=”:A.jpg”>.jpg” alt=”:B.jpg”>.jpg” alt=”:C.jpg”>

.jpg” alt=”:D.jpg”>.jpg” alt=”:E.jpg”>.jpg” alt=”:outgroup.jpg”>

1a) Establish a numeric scoring system for each of 4 traits (4pts): (Plesiomorphic traits should always be scored as 0) (4 pts)

1 2 3

1) # of shell whorls:

present absent

2) shell spines:

smooth scalloped frilled

3) Foot margin:

short tall

4) Eye stalk length:

1b) For each species, score each trait: (3 pts)

TAXON (ingroup)

1) # of whorls

2) Spines

3) Foot margin

4) Eye stalk

A

B

C

D

E

1c) From this comparison, reconstruct the most parsimonious phylogeny. (be sure to label character state changes on the branches and do not forget to include the outgroup!) hint you can also use additional features not officially listed above to help you (5 pts.)

1d) Which structure seems to have evolved/changed independently in two separate lineages (homoplasy) (2 pts)?

1e) Additional to this morphological data you obtain DNA sequence from a hyper-variable region that is approximately 11 nucleotides long. Assuming that the rate of change in this gene is one base change per million years, how long ago did Taxon A share a common ancestor with Taxon B? (2 pts) Hint you need to compare state changes with the outgroup to be able to score a base substitution as an actual change Which species, A or B, has evolved faster? (1 pt)

NUCLEOTIDE SITE

TAXON 12345678901

sp. A GT-ATCTGTAC

sp. B GGGAGCTATGC

sp. C GT-CTCTGTGA

sp. D GCGAGCTATGG

sp. E GT-CTCTGTAC

Outgroup GCGAGGTGAGC

Short Essays:

Once believed to be a primitive animal, modern research on Placozoa shows that this is not the case. Moreover (conversely) the study of Ctenophores has shown that this relatively complex animal may be as primitive as sponges. What does this indicate about the process of evolution?

How does ammonia negatively affect the physiology of an animal cell? How do animals avoid the build-up of high (NH3) concentrations?

Why are almost half of the animal phyla exclusively marine?

What attributes do jellyfish have that give them an edge over fish in environments stressed by climate change, eutrophication, and overfishing? What are the consequences of a pelagic ecosystem that has undergone a transition to being dominated by jellyfish? (This is from your reading)

How do the life histories of Anthozoans and Scyphozoans different? How has this led to differences in their ecological distribution and dominance?

What is chitin? How is it similar to cellulose? (you may draw a portion of the molecule if you wish). Why is this an important material?

List 2 adaptations that evolved in the ancestors of modern insects that helped them overcome physiological challenges (e.g. fluid balance, reproduction, food acquisition) associated with terrestrial life. Note! Having an exoskeleton was a pre-existing condition and, while it was obviously was an important attribute in the success of Arthropods colonizing land, you may not use this as one of your examples.

What is the morphological and gene expression (molecular) evidence for wings evolving from existing arthropod appendages and not outgrowths of the thoracic body wall as was originally thought?

Why was the production of silk an important evolutionary innovation for the spiders? (hint: what are the functions of spider silk?)

Why do insects dominate most terrestrial landscapes?