Lecture 16

Question 1

what percentage of the oxygen do protists produce?

Answer 1

Protists produce at least half of the oxygen in the Earth’s atmosphere

Question 2

from which protist do we get oil for cars?

Answer 2

We get oil for cars from pressure-cooked diatoms (a photosynthetic protist)

Question 3

characteristics of protists?

Answer 3

Range in size: microscopic to 75 meters long (giant kelps)

LIVING ARRANGEMENTS: moist environments
Most are unicellular organisms
Some live in colonies: loosely connected groups of cells
Some are multicellular
Some in symbiotic relationships

MOTILITY
cytoplasmic extensions called: Pseudopodia
multiple cilia, 1-2 flagella
a few are nonmotile (don’t move)

Question 4

where do protists live?

Answer 4

Most live in the water: fresh & marine water
Make up most of the plankton: floating, small organisms that are the base of the food chain in aquatic ecosystems

Terrestrial protists: damp places like soil

Parasites live in host’s bodily fluids

Question 5

what is the nutrition of the protists?

Answer 5

Photoautotrophs: perform photosynthesis using the light

Chemoheterotrophs: take in organic material from their surroundings to be used as both a source of energy and as a source of carbon.

Mixotrophs: alternate between photoautrophic & chemoheterotrophic. Ex Euglenids

Question 6

absorptive nutrition?

Answer 6

absorb monomers from surroundings.

Ex. fungus-like slime molds, parasitic Trypanosomes

Question 7

ingestive nutrition?

Answer 7

take in (ingest) food, then digest it.
Animal-like protists: amebas, ciliates.

Question 8

how do protists move?

Answer 8

• pseudopodia
• cilia
• flagella

Question 9

3 main groups of protists?

Answer 9

Plant-like: photosynthetic
Animal-like: ingest/digest
Fungus-like: decompose

Question 10

cell wall of seaweeds/ green algae is made up of?

Answer 10

cellulose

Question 11

characteristics of Diatoms?

Answer 11

Unicellular algae
Major component of phytoplankton
Photosynthetic: By themselves thought to make 20-50% of O2 on Earth
Organic product of photosynthesis mostly oil (fats) but do make carbs as well.

Question 12

nutrition of euglena?

Answer 12

Euglena: mixotroph: Photosynthesis & heterotrophy

Question 13

plant like protists?

Answer 13

seaweeds, green algae, diatoms, volvox, euglena

Question 14

animal like protists?

Answer 14

amoeba, paramecium, stentor,

Question 15

examples of protist decomposers?

Answer 15

water mold, slime mold

Question 16

role of protists in the ecosystem?

Answer 16

• release oxygen (50% of earth’s o2)
• Basis of Aquatic Food Webs (Algae are responsible for most of the primary production in aquatic habitats, are eaten by the others, multi and unicellular)
• Symbiosis:
  Mutualism, Lichen
  Parasitism Trypanosma
  Parasitism Plasmodium

Question 17

characteristics of Symbiosis: Parasitism Plasmodium

Answer 17

2 hosts: mosquitos & humans

Causes MALARIA
200-500 million people get sick every year
2 million people (mostly children under 5) die every year: 1 every 30 seconds
Antimalarial drugs (parasite) & pesticides (kill mosquitos) loosing effectiveness: resistance to drugs by parasite & mosquito
Mosquito nets effective