Chapter 25 Flashcards
Origin & Diversification of Eukaryotes
1
Q
What are the 3 fundamental elements of Eukaryotes?
A
- Nucleus
- Organelles
- Structurally complex cytoskeleton
2
Q
Protist
A
informal name for a diverse group of mostly unicellular eukaryotes
3
Q
What does a structurally complex cytoskeleton allow a eukaryote to do?
A
- have asymmetrical form
- move, feed, grow
4
Q
List the 3 stages of eukaryotes.(early records)
A
- initial diversification
- multicellular & appearance of novel features
- Rise of large eukaryotes
5
Q
List the characteristics of initial diversification
A
- single celled
- all had a nucleus, flexible membrane, and cytoskeleton
- varied in size and shape
6
Q
List the novel (new) features in the second stage
A
- complex multicellularity - organisms had differentiated cell types
- sexual life cycles
- photosynthesis
7
Q
List the characteristics in that gave rise to large eukaryotes.
A
- body sized maximized
- increased taxonomic diversity
- increase types of morphological differences
- soft bodied
8
Q
Endosymbiosis
A
symbiotic relationship where one organisms lives in the body or cell of another
9
Q
Plastids
A
general term for chloroplasts and related organelles
10
Q
Endosymbiont Theory
A
that mitochondria & plastids were formerly small bacteria that began living within larger cells.
11
Q
Primary endosymbiosis
A
engulfment of a prokaryote by another living cell and incorporation of that prokaryote as on organelle
12
Q
What stage of endosymbiosis is responsible for the initial eukaryotes mitochondria and chloroplast?
A
Primary endosymbiosis
13
Q
Serial endosymbiosis hypothesis
A
suggesting that mitochondria evolved before plastids through a sequence of endosymbiotic events.
14
Q
Secondary endosymbiosis
A
a eukaryotic cell engulfs a cell that has already undergone primary endosymbiosis.
15
Q
How did secondary endosymbiosis occur?
A
when photosynthetic eukaryotic algal cells were ingested by heterotrophic eukaryotes.
16
Q
Multicellularity in different eukaryotes arose ___.
A
independently
17
Q
Multicellular colonies
A
complex of connected cells with little to no cellular differentiation
18
Q
Complex mutlicellularity
A
complex of connected cells that are differentiated
19
Q
Co-opting
A
changes in how existing genes are used rather than addition of new genes
20
Q
List the 4 “Supergroups” of Eukaryotes
A
- Excavata
- SAR
- Archaeplastida
- Unikonta
21
Q
List the 3 clades Excavata has
A
- Diplomonads
- Parabasalids
- Euglenozoans
22
Q
List the characteristics of Dipolomonads
A
- Most in anaerobic environments
- Highly reduced mitochondria called mitosomes
- Many are parasites
23
Q
Give an example of Dipolomonads
A
giardia intestinalis - lives in mammals intestines and is found in creek water
24
Q
List the characteristics of Parabasalids
A
- most in anaerobic environments
- highly reduced mitochondria called hydrogenosomes
- many are animal symbionts or parasites
25
Give an example of parabasalids symbiont and parasite.
Its a gut mutualist in termites
human parasite called trichomonas vaginalis
26
List the characteristics of Euglenozoans
1. highly diverse (hetetrophs, autotrophs, parasites)
2. flagella with spiral or crystalline structure
27
What kind of "troph" is euglenozoans?
Mixotroph - meaning it can switch how it obtains energy
28
Give examples of Euglenozoans
1. euglenid - african sleeping sickness from being bitten by flies
2. kinetoplastid
29
List the 3 groups of SAR
1. Stramenopiles
2. Alveolates
3. Rhizarians
30
List the characteristics of Stramenopiles
1. evolved via secondary endosymbiosis
2. vital photosynthetic organisms
31
List the two groups under stramenopiles
1. diatoms
2. brown algae "sea weed"
32
What do diatoms form ?
the bases of the food web
33
List the characteristics of Diatoms
1. unicellular algae with glass like (silicon dioxide) cell wall
2. most abundant photosynthetic organism in aquatic & marine systems
3. Has significant effects on global CO2
34
List the characteristics of Brown Algae or Sea Weed
1. largest, most complex of all algae
2. all are multicellular
3. most are marine
4. Plant like structures but are NOT plants
5. Pneumotocsys - gas filled floats
35
List the characteristics of Alevolates
1. likely evolved via secondary endosymbiosis
2. have membrane - enclosed sacs called alveoli
36
what is alveoli?
membrane enclosed sacs
37
List the two groups under Alveolates.
1. dinoflagellates
2. ciliates
38
list the characteristics of Dinoflagellates
1. habitat is in aquatic & marine systems
2. cells are armored with cellulose plates
3. have 2 flagella
4. some are mixotrophs - photosynthetic + heterothrophic
39
What is caused by dinoflagellates?
Red tide due to extreme population growth
can make the ocean light (blue colored)
40
List the characteristics of ciliates.
1. use cilia (hair like) to move + feed
2. most are predators of bacteria + other protists
3. their structure varies among organisms
41
List the characteristics of Rhizarians
1. many are amoebas but not all amoebas are rhizarians
2. amoebas move and feed by pseudopodia, extensions that bulge from the cell surface.
42
List the 2 groups under Rhizarians
1. Forams
2. Cercozoans
43
List the characteristics of Forams
1. have porous shells called tests
2. found in aquatic + marine systems
3. the hair like extensions called pseudopodia extend through holes in tests that help it swim, feed, and formation
4. many are in symbiosis with photosynthetic algae
44
List the characteristics of Cerozoans
1. group consisting of ameboid + flagellated protists that feed with threadlike pseudopodia
2. found in marine, freshwater, and soil
3. most are heterotrophic but some are autotrophs and mixotrophs
4. parasitic symbiosis - predators
45
what group is the most abundant in moist soil?
cercozoans
46
List the 3 groups under Archaeplastida
1. Red Algae
2. Green algae
3. Plants
47
List the characteristics of Red Algae
1. coloration due to accessory pigment in phycoerythrin (varies with depth)
2. Most are multicellular
3. Largest are seaweed
4. sexual reproduction
48
Give an example of red algae
nori (sea weed thats wrapped in sushi)
49
List the two groups under Green algae
1. charophytes -closely related to plants
2. Chlorophytes
50
List the characteristics of Chlorophytes
1. more than 7,000 species
2. most are in freshwater but some are found in marine or terrestrial
3. most reproduce sexually with bi-flagellated gametes
4. mix of unicellular and multicellular
51
List the 2 major groups (or clades) under Unikonts
1. Opisthokonts
2. Amoebozoans
52
What is included in Opisthokonts?
1. animals
2. fungi
3. some protists
53
List the characteristics of Amoebozoans
1. lobe shaped or tube shaped pseudopodia
2. most are hetetrotrophs but some are detritives
54
what are detritives?
under the clade of amoebozoans and feed on dead organic organisms or a bi-product of organisms
55
What are the two major groups under Amoebozoans?
1. Tubulinids
2. Slime molds
56
List the characteristics of Tubulinids.
1. unicellular
2. common in soil, freshwater, marine
3. nickelodeon shaped
57
List the characteristics of Slime molds
1. multicellular
2. produce spores
3. once believed to be fungi
58
Where are protists found?
freshwater and marine systems and also on moist terrestrial habitats
59
Protists exhibit what types of ways of obtaining energy
1. photoautotrophy
2. hetetrotrophy
3. mixotrophy
60
The chloroplasts of all of the following are thought to be derived from ancestral red algae, except those of
green algae
61
In a sample of pond water, a new organism is identified with the following characteristics: It consists of 70 cells surrounded by rigid cell walls that join the cells together. Inside each of these identical cells are mitochondria and chloroplasts. Such an organism would most likely be classified as a
colonial photosynthetic eukaryote.
62
Healthy individuals of Paramecium bursaria contain photosynthetic algal endosymbionts of the genus Chlorella. When within their hosts, the algae are referred to as zoochlorellae. In aquaria with light coming from only one side, P. bursaria gathers at the well-lit side, whereas other species of Paramecium gather at the opposite side. The zoochlorellae provide their hosts with glucose and oxygen, and P. bursaria provides its zoochlorellae with protection and motility. P. bursaria can lose its zoochlorellae in two ways: (1) if kept in darkness, the algae will die; and (2) if prey items (mostly bacteria) are absent from its habitat, P. bursaria will digest its zoochlorellae.
Which term best describes the symbiotic relationship of well-fed P. bursaria with their zoochlorellae?
mutualistic (each species benefits from the other)
63
Rhizarians that feed using threadlike pseudopodia include which of the following group(s)?
I. forams
II. red algae
III. cercozoans
IV. green algae
forams and cercozoans
64
In a synthetic biology experiment, you are given a task to design a new species of aquatic protist. Your design should account for the following characteristics:
1. The protist functions as a primary producer.
2. It cannot swim on its own.
3. It must stay in well-lit surface waters.
4. It must be resistant to physical damage from wave action.
Based on these criteria, you decide to model your creation after a(n)
Diatom
65
An individual mixotroph loses its plastids yet continues to survive. Which of the following most likely accounts for its continued survival?
It engulfs organic material by phagocytosis or by absorption.
66
What does scientific evidence indicate to be the correct sequence of these events, from earliest to most recent, in the evolution of life on Earth?
1. origin of mitochondria
2. origin of multicellular eukaryotes
3. origin of chloroplasts
4. origin of cyanobacteria
5. origin of fungal-plant symbioses
4, 1, 3, 2, 5
67
According to the endosymbiotic theory of the origin of eukaryotic cells, how did mitochondria originate?
from engulfed, originally free-living proteobacteria
68
