Biol. 261 F00 - Unit One Review

(If you have older 10th Edition, add one to each chapter, so Ch. 9 is Ch. 10)

Ch. 9: 180-183; 189-194; RQ-9: 1, 2, 4, 10-13

Ch. 10: All; RQ-10: 2-7, 9

Ch. 11: All; RQ-11: 1, 6, 8-11

Ch. 12: 240-241, 243-252; RQ-12: 3-5, 8-11

(Porifera only, not Mesozoa, Placozoa)

Ch. 13: 253-266, 277-280; RQ-13: 2-5, 11

(Cnidaria only, not Ctenophora)

Also, see p. 110 (Burgess Shale)

Ch. 14: 281-296, 300-302; RQ-14: 1-3, 8-10, 13

(Platyhelminthes only, not Nemertea, etc.)

Cladograms on pp.: 278, 301

Web Cladogram Exercise, Quiz, Terms
 

Lecture notes on systematics

(see Web cladogram practice assignment)

Cladistics

clade vs. grade

snip rule

swivel node rule

sister taxon

types of similarity

homology vs. homoplasy

synapomorphy vs. plesiomorphy

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"protist" lecture (Note: There is more here than I covered in lecture

or will cover in exam!)

 

Protists: dinoflagellates,Euglena, Volvox, Codosiga, Amoeba, forams, radiolarians, Toxoplasma, Plasmodium, Paramecium

Topics

"Protista" is a grade, not a clade

- it is a paraphyletic taxon

- avoid these in Biol. 261

Diversity of single-celled eukaryotes ("protists")

Note: Much of the following information on protists was not covered in as much detail in lecture.

In intro biology, you probably learned about:

5 Kingdoms

prokaryotes

protists

plants

fungi

metazoans

but these are functional/nutritional groupings.

Some are not clades and hence not acceptable taxa:

1) Paraphyletic groupings:

prokaryotes = All life except eukaryotes

protists = All eukaryotes except plants,

fungi, animals

2) Inconsistent as functional/nutritional

categories - example "plants"

a) What about brown, red and green algae?

b) What about single-celled plants such as

diatoms, dinoflagellates, cyanobacteria

3) Grouping "prokaryotes" includes vastly

different subgroups, Archaea and

Bacteria, that last shared a common

ancestor about 3.5 billion years ago

An alternative phylogenetic approach:

Recognize three basic "superkingdoms"

Archaea, Bacteria, Eucarya

(Archaebacteria, Eubacteria, Eukaryota)

Generally, refer to:

"eukaryotes" (monophyletic)

not:

"protists" (paraphyletic)

 

Most current evidence suggests our nucleus

more closely resembles some Archaea,

but this is still controversial

Within Eukaryota, basal groups lack

mitochondria (but have nucleus,

mitosis) - example: Giardia

Mitochondria known to have arisen by

endosymbiosis between early eukaryote

and alpha-purple bacterium

Plastids have arisen multiple times from

cyanobacteria or eukaryote endosymbionts - examples: chloroplasts, euglenoplasts

Endosymbiosis between 2 eukaryotes

is known –> combined organism

- example:

Mesodinium is a ciliate + cyptomonad

with plastids of two separate origins

Main eukaryotic diversity (based on rDNA sequence similarity):

"Stem" groups - example: Giardia

(have nucleus but lack mitochondria)

Eukaryotes with mitochondria

"Middle" groups - example: Euglena

"Crown" Group

cryptomonads

heterokonts: diatoms, brown algae

alveolates: ciliates, dinoflagellates, apicomplexans (sporozoans)

red algae

green algae (plus land plants)

fungi + choanoflagellates + metazoans

Older "protozoa" categories

(based on locomotory, nutritional

similarities):

• Sarcomastigophora

(flagella/pseudopodia)

examples:

Euglena, Volvox, Amoeba

forams, heliozoans,

radiolarians

• Apicomplexa (Toxoplasma,

Plasmodium)

• Myxozoa (now considered cnidarians)

• Microspora

• Ciliophora (ciliates)

This system of organization has been mostly abandoned but most of these groups are still valid

(but not Sarcomastigophora)

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"protist" Examples Emphasized:

Euglena

– widely studied as typical flagellate

– freshwater habitat

– plastid came from green alga

 

Amoeba

– widely studied "naked" amoeboid

– uses pseudopodial locomotion

with lobopodia

– other "sarcodina" have test

and axopodia

forams, radiolarians

"ooze" on sea floors

 

"flagellates" or "amoeboids" are each polyphyletic

 

Heterokonts

diatoms – unicellular phytoplankton

kelp - multicellular

 

Alveolates

dinoflagellates

– important "phytoflagellates"

– free-living or symbiotic inside corals, anemones (zooxanthellae)

– includes "plants" & "predators"

ciliates (Paramecium)

– highly diverse group

– usually large (10 µm to 3 mm)

– macro- and micronucleus

– conjugation – adults exchange

haploid micronuclei, come away different (Fig. 11-27)

apicomplexans

– endoparasites lacking motility

– have "apical complex"

– Toxoplasma is cat parasite

that also infects AIDS patients

– Plasmodium causes malaria

transmitted by mosquitoes

(see Fig. 11-20)

 

"Crown" eukaryotes

Chlorophytes

– one or more cells

– green algae and land plants

– (+ red algae?)

– Volvox example of colony of cells

 

Fungi

 

Choanoflagellates (Codosiga)

– often colonial

– "collar" cells resemble feeding

cells of sponges

 

Metazoa (multicellular animals)

 

 

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Notes from sponge lecture:

Terms: ostia, spicules, spongin, collagen

Taxa: Metazoa, Porifera, Eumetazoa

Topics

Metazoan - derived features

Sponges

first large fossil animals

origin from colonial eukaryotes

sponge anatomy

 

Metazoa (multicellular animals)

Metazoan synapomorphies:

Multicellularity (but certain other eukaryotes

are also multicellular)

Intercellular cytoplasmic communication

Septate and desmosomal "gap" junctions

between cells

Extracellular production of cross-linked

collagen

Blastula larval stage

 

Phylogeny (simplified)

Metazoa

Porifera (Sponges)

Eumetazoa (tissues, expanded gut)

Cnidaria (radial symmetry)

Bilateria (bilateral symmetry)

 

Porifera (Sponges)

Aquatic animals

Can be soft-bodied but most firm to woody

– internal skelton of many tiny calcareous or siliceous spicules

– many also have tough sponge fibers

Sponges are perforated by a nework of canals

– water moves to chambers

– moves to chambers lined with "collar" cells

(Choanocytes)

– exits through a corridor to one or more

large oscula

Sponges are highly specialized to filter feed.

– One sponge can filter multiple liters of water

Sponges have tissues (despite what text says):

Complex array of cell types

No organs or nervous system

Only two "systems"

canals/chambers

skeleton

 

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Notes from cnidarian lecture:

 

Cnidarian Terms

 

Describe a typical hydrozoan life cycle

Compare life cycle of:

Hydrozoa, Anthozoa, Scyphozoa

What is a nematocyst and how does it relate to a cnidocyte?

How does Hydra compare with a sponge?

How does an anemone compare with a sponge?

What specializations are related to coloniality?

 

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Notes from flatworm lecture:

symbiosis -

commensalism, mutualism, parasitism

complex life histories: intermediate/definitive hosts

Trematoda (flukes) life cycles

Types of interspecific interactions

 

Parasite adaptations

Platyhelminthes (flatworms):

planuloid hypothesis

Types of interspecific interactions:

symbiosis -

commensalism, mutualism, parasitism

complex life histories:

intermediate/definitive hosts

Trematoda (flukes) and Tapeworm life cycles

Parasite adaptations

Platyhelminthes Terms

epithelium (ectoderm)

parenchyma (mesoderm)

acoelomate

ocelli

rhabdite

tegument

syncytial

complex life histories

intermediate/definitive hosts

Trematoda (flukes):

miracidium, sporocyst, rediae, cercariae,

metacercariae

opisthaptor (Monogenea) scolex (Cestoda)

proglottid