Lecture 5

Question 1

Distinguishing features of a prokaryote

Answer 1

No nuclear membrane
No membrane-enclosed organelles
No separate cellular compartments for genetic material, proteins and metabolites

Question 2

Age of prokaryotes

Answer 2

Appear ~3.6 Ga

Question 3

Dimension of prokaryotes

Answer 3

< 10 um

Question 4

Distinguishing features of a eukaryote

Answer 4

True nucleus with nuclear membrane
Membrane-enclosed organelles
Genetic material (chromosomes) enclosed in nucleus

Question 5

Age of eukaryotes

Answer 5

Oldest fossils 1.6-2 Ga

Question 6

Shared features of protists

Answer 6

Most species are single-celled; eukaryotic cell organization
Sexual or asexual reproduction
Many bear plastids and/or well-developed flagella

Question 7

Generalities of protists

Answer 7

Small
Many secrete protective shell/test
Various types of nutrition
Highly sensitive to environmental stimuli
Large range of reproductive strategies
Single-celled but some form colonies

Question 8

Pelagic

Answer 8

Live in the water column

Question 9

Benthic

Answer 9

Live in or on the sediment floor

Question 10

Plankton

Answer 10

Drifters: Organisms that move with the currents (as opposed to the free-swimming Nekton)

Question 11

Give examples of the size range of protists

Answer 11

Variable size
Bacteria-giant jellyfish

Question 12

Phytoplankton

Answer 12

Those that photosynthesize

Question 13

Zooplankton

Answer 13

Those that eat other organisms

Question 14

Name the 5 types of photosynthetic protists

Answer 14

Acritarchs
Coccolithopores
Diatoms
Dinoflagellates
Silicoflagellates

Question 15

Morphology of acritarchs

Answer 15

Cyst or phycoma
With or without ornamentation (e.g., spines)

Question 16

Acritarch composition

Answer 16

Composed of refractory original material

Question 17

Ecology of acritarchs

Answer 17

Likely the remains of different kinds of organisms, marine or terrestrial aquatic environments
Likely algal affinities

Question 18

Acritarch stratigraphy

Answer 18

Precambrian-present

Question 19

Acritarch acme

Answer 19

Paleozoic

Question 20

Acritarch importance in rock record

Answer 20

Useful biostratigraphic tracers

Question 21

Coccolithophores protist morphology

Answer 21

Spherical coccolithophore
Cell protected by CaCO3 plates (coccoliths)

Question 22

Coccolithophores fossil morphology

Answer 22

Coccoliths - small rounded plates

Question 23

Coccolithophores ecology

Answer 23

Photoautotrophs
Planktic
Marine

Question 24

Coccolithophore stratigraphy

Answer 24

Jurassic-present

Question 25

Coccolithophore acme

Answer 25

Late Cretaceous

Question 26

Possible roles of the coccoliths

Answer 26

Decrease predation Decrease penetration by bacteria Increase buoyancy

Question 27

2 types of diatoms

Answer 27

Pennate Centric

Question 28

Diatom morphology

Answer 28

Cell protected by a transparent SiO2 frustule Colony or solitary

Question 29

Diatoms ecology

Answer 29

Planktonic, benthic (moist or submerged surfaces) and sympagic (sea-ice) Photoautotrophs All aquatic environments (lakes, rivers, oceans, etc.) Complex life cycle, has sexual and asexual phases

Question 30

Diatoms stratigraphy

Answer 30

Mesozoic-present

Question 31

Diatoms acme

Answer 31

During Cenozoic

Question 32

Frustule structure

Answer 32

Porous SiO2 matrix Composed of 2 valves and multiple ring-shaped girdle bands

Question 33

Centric diatoms

Answer 33

Radial symmetry Solitary cells or colonies Large diversity in size

Question 34

Pennate diatoms

Answer 34

Bilateral symmetry Solitary cells or colonies Large diversity of size

Question 35

What does dinoflagellate signify?

Answer 35

Whirling whip Characteristic movement: 2 perpendicular flagella

Question 36

Zooxanthellae example

Answer 36

Dinoflagellates are taken as residents in soft tissues of coral

Question 37

Pro of zooxanthellae

Answer 37

Allows the organism to grow very quickly

Question 38

Morphology of dinoflagellate protist

Answer 38

Theca composed of cellulosic plates

Question 39

Dinoflagellate morphology of fossil

Answer 39

Cyst composed of refractory organic material, a few taxa are composed of CaCO3

Question 40

Dinoflagellate ecology

Answer 40

Mostly epipelagic, a few are benthic Phototrophs, mixotrophs or heterotrophs Aquatic: lacustrine (some species) to oceanic (many species)

Question 41

Dinoflagellate stratigraphy

Answer 41

Triassic-present

Question 42

Dinoflagellate acme

Answer 42

During Cretaceous

Question 43

Dinoflagellate cysts

Answer 43

Envelope that protects the cell Is fossilizable