BIS 2C Lecture Notes - Lecture 26: Blastula, Calcareous Sponge, Mesohyl

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redwombat135

7 Mar 2018

School

UC-Davis

Department

Biological Sciences

Course

BIS 2C

Professor

Clare Casteel, Neelima Sinha, Phil Ward

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Document Summary

Choanoflagellates: small group of aquatic heterotrophic eukaryotes (protists, some unicellular, others colonial, collar cell: ovoid in shape, with a collar of microvilli (tentacles that capture food particles) surroundng the single agellum. Unique: trait that arose only in the group (nowhere else in the tree of life) multicellularity is a synapomorphy of animals but is not unique opisthokonts: Fungi: multicellular (separate synapamorphy) all opisthokonts are heterotrophs, probably an ancestral condition from long before. Autotrophy is a derived condition in other euks. Separates from sponges and placozoans, so now we arent sure if it is a synapomorphy. > blastula, hollow ball with liquid filled cavity called the blastocoel inbetween. > gastrulation, cells on outisde migrating inside the blastula inpocketing . > production of two layers: endoderm and ectoderm with blastocoel diploplastic: only endoderm and ectoderm (ambiguity) went through futher modifications) Diploblasty evolved where the gut evolved (they are essentially the same thing)

Related Questions

QUESTION 1

The âCambrian Explosionâ describes the relatively sudden appearance of __________ in the fossil record in the Cambrian.

		Metazoans
		Eukaryotes
		Algae
		Cephalopods
		Chocolate

0.5 points

QUESTION 2

Poriferans lack:

		Extracellular matrix
		Organs
		Choanocytes
		Nuclei

0.5 points

QUESTION 3

Which of the following has no terrestrial species?

		Brachiopoda
		Nematoda
		Mollusca
		Arthropoda

0.5 points

QUESTION 4

The metazoan phylum with the greatest diversity (i.e., number of species) today is:

		Arthropoda.
		Annelida.
		Cnidaria.
		Mollusca.

0.5 points

QUESTION 5

Segmentation is a feature of:

		Cnidarians
		Platyhelminthes
		Nematodes
		Annelids

0.5 points

QUESTION 6

A coelom is:

		Fun for the whole family.
		A fluid-filled body cavity forming within the mesoderm.
		A stinging cell found in cnidarians.
		A characteristic of flatworms.
		A fluid-filled body cavity between the mesoderm and endoderm.

0.5 points

QUESTION 7

How old is the earliest fossil evidence of life?

		3.8 Ma
		3.8 Ga
		1.8 Ga
		543 Ma

0.5 points

QUESTION 8

Which of the following is found only in bilaterians?

		Mesoderm
		Choanocytes
		Radial symmetry
		Gastrulation
		Nougat

0.5 points

QUESTION 9

Which of the following is not an explanation put forward for the Cambrian Explosion?

		Oxygen increase
		Revolution in substrate use
		Predation
		Global warming

0.5 points

QUESTION 10

Cnidarians are distinct from other animals in having:

		A can-do attitude
		Nematocysts
		Chitin
		Collagen
		Bilateral symmetry

0.5 points

QUESTION 11

Which of the following is a group within Platyhelminthes?

		Insecta
		Velveeta
		Bivalvia
		Cestoda
		Hydrozoa

0.5 points

QUESTION 12

Of Fungi, Metazoa, and Plantae, which two are thought to be more closely related to each other than they are to the third?

		Metazoa and Plantae
		Fungi and Plantae
		Fungi and Metazoa

0.5 points

QUESTION 13

The Cryogenian is a period of the Proterozoic characterized by:

		Low self esteem
		Earliest fossils of life
		Cooling and glaciation
		Sudden appearance of fossils with hard parts
		Increase in oxygen

0.5 points

QUESTION 14

Which of the following is thought not to have been abundant in the environment of the early Earth when life originated?

		Oxygen
		Nitrogen
		Methane
		Water

0.5 points

QUESTION 15

Of Archaea, Bacteria, and Eukarya, which two are thought to be more closely related to each other than they are to the third?

		Bacteria and Eukarya
		Archaea and Bacteria
		Archaea and Eukarya

0.5 points

QUESTION 16

The increase in oxygen that occurred around 2.3 Ga is referred to as:

		The Snowball Earth
		The Permian Extinction
		The Cambrian Explosion
		The Great Oxidation Event
		Friday

0.5 points

QUESTION 17

A lophophore is:

		A feeding structure found in brachiopods and bryozoans.
		A reproductive structure found in annelids and molluscs.
		A photoautotroph.
		Available at Targetâ¢.
		Absent in all lophotrochozoans.

0.5 points

QUESTION 18

One of the main divisions of protostomes is:

		Electronica
		Cnidaria
		Eukarya
		Lophotrochozoa
		Deuterostomia

0.5 points

QUESTION 19

If, as some studies have suggested, Ctenophora is the sister-taxon to other metazoans, this would imply that:

		Poriferans are not animals.
		Cnidarians are not monophyletic.
		We are all hosed.
		Nervous systems evolved more than once, or were lost by Porifera.
		Ctenophorans are cnidarians.

0.5 points

QUESTION 20

The chambered shells of fossil cephalopods contribute to:

		Feeding.
		The Red Cross.
		Respiration.
		Control of buoyancy.
		Propulsion.

BIS 2C Lecture Notes - Lecture 26: Blastula, Calcareous Sponge, Mesohyl

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