Topic 8 - Orgin of Eukarya/Protists Flashcards
1
Q
What are ecological relationships?
A
- pairs of species can be grouped on their ecological interactions
2
Q
what is mutualism (+ +)?
A
- both species A and B benefit from the other’s presence.
-both species benefit
example: coral and algae
3
Q
what is competition ( - - )?
A
- both species A and B suffer from each other’s presence.
- both species feed on similar prey, they are negatively impacted by the presence of the other because they will have less food
- example: cheetah and lions
4
Q
what is predation (- +)?
A
- when species A easts species B
example:
wolves hunting moose
owls hunting mouse
5
Q
what is parasitism (- +)?
A
- species A steals nutrition or other resources from species B
- one in which one organism, the parasite, lives off of another organism, the host, harming it and possibly causing death.
- example: humans and mosquitoes.
6
Q
what is commensalism (0 +)?
A
- Speices A lives on or with Species B, but neither harms nor benefits species B.
- example
bird making a nest in a tree
whales and barnacles.
7
Q
what is amensalism (- 0)?
A
- Species A harms species B. Species B does nothing for species A
-only one organism is hurt.
- example:
cattle trample on grass
penicillin kills bacteria
8
Q
what does + mean?
A
- beneficial
9
Q
what does - mean?
A
- negative
10
Q
what does 0 mean?
A
- neutral
11
Q
what is a symbiotic relationship?
A
- when members of two species live in close, often obligatory, contact with each other.
12
Q
what does syn mean?
A
together
13
Q
what does bio mean?
A
life
14
Q
what relationships does symbiosis involve?
A
- mutualism, commensalism or parasitism.
15
Q
what is called the host?
A
- if one species is much larger than the other.
16
Q
what is a species called that is smaller than the other?
A
- symbiont
17
Q
what is a endosymbiotant?
A
- if the prokaryote is inside the host organism
18
Q
what does endo mean?
A
- within
19
Q
when did eukaryotes arise?
A
- The first eukaryotic cell arose more than a billion years after prokaryotes appeared.
- The oldest fossil eukaryote is 1.8 billion years
20
Q
Eukaryotic vs Prokaryotic
A
- eukaryotes have DNA in linear chromosomes in membrane-bound nuclei.
- eukaryotes have other membrane-bound organelles such as
mitochondria and plastids (e.g. chloroplasts) - eukaryotes are often much larger than prokyotes.
- eukaryotes have a cytoskeleton that allows them to change change shape, for example being able to engulf particles
21
Q
what is the orgin?
A
- originally hypothesized that
eukaryotic cells arose
gradually from a prokaryotic
ancestor
a. ancestral pre-eukaryotic cell very likely to have been a
member of the Archaea
22
Q
how did the ancestral host cell develop some structures?
A
- gradually by
infoldings of cell membrane
– endoplasmic reticulum
– nuclear envelope - endosymbiosis also played an important role.
23
Q
what did the ancestral nucleated host cell take on?
A
- endosymbiotic aerobic
heterotrophic prokaryote, which was probably a proteobacterium* that
used oxygen and organic matter to
make energy - this eventually led to the formation of mitochondria.
24
Q
what did members of other lineages engulf?
A
- photosynthetic prokaryotes.
- they were most likely cyanobacteria that used
light and CO2 to make organic
compounds - then they became photosynthetic protists and plants.
a. the endosymbionts became plastids
(e.g., chloroplasts)
25
what is serial endosymbiosis?
- first mitochondria
and then plastids were
endosymbiotically acquired by the
ancestors of photosynthetic
eukaryotes
26
What’s the evidence for endosymbiosis in
evolution of eukaryotes?
1. mitochondria and chloroplasts have their
own DNA, which they replicate independently
of nuclear DNA
2. this DNA is circular, as is prokaryotic DNA
3. plastids (e.g., chloroplasts) have 2 or more
cell membrane layers
* 2 membranes if engulfed a free cyanobacteria
*2 or more if engulfed other eukaryote.
27
what is primary endosymbiosis?
- refers to a free-living
prokaryote being taken on by a eukaryotic cell
- The eukaryote is englfed a prokaryote, which led to the creation of mitochondria.
28
what is secondary endosymbiosis?
- refers to the taking on of a
photosynthetic (plastid-containing) eukaryotic cell by
a heterotrophic eukaryotic cell
- the resulted organelles will be very complex and will be surrounded by serval additional cell memebranes.
- occurs when a eukaryotic cell engulfs a cell that has already undergone primary endosymbiosis.
29
what is the difference between primary and secondary endosymbiosis?
- Primary endosymbiosis occurs when a eukaryotic cell engulfs and absorbs a prokaryotic cell, such as a smaller cell that undergoes photosynthesis (eg. cyanobacteria).
- Secondary endosymbiosis occurs when a eukaryotic cell engulfs and absorbs another eukaryotic cell. it produces green and brown algae.
30
what is horizontal gene transfer
through endosymbiosis?
- occurs through genome fusion between different species when two symbiotic organisms become endosymbiotic.
- This occurs when one species is taken inside the cytoplasm of another species, which ultimately results in a genome consisting of genes from both the endosymbiont and the host.
31
what is metabolic diversification?
- it sets the stage for a second wave of diversity.
-the different metabolic strategies that organisms have evolved to obtain energy.
31
what is the second wave catalyzed by?
- structural diversity of eukaryotic cells.
32
what is structural diversity?
- the range of different physical landscapes within a habitat; the more diversity, the more opportunities for different organisms to thrive.
33
what was the third wave of diversification?
- the origin of multicellular bodies in several eukaryotic cells evolved new ways of reproduction.
34
what are multicellular bodies?
- composed of more than one cell, with groups of cells differentiating to take on specialized functions.
35
what is Mitosis?
- in mitosis,
one diploid
cell divides
once to form
two diploid
(2n) cells
- so there is an original cell with 2n=4
- then chromosomes replicate.
then one diploid cell divides into two diploid cells. (2x (2n=4)
36
What is meiosis?
- in meiosis,
one diploid
cell divides
twice to form
four haploid
(1n) cells
(reduction
division)
- so there is an original cell with 2n=4
- then chromosomes replicate.
then one diploid cell divides into two diploid cells. (2x (2n=4)
- then the two diploid cells divide again to form 4 gamete cells which are halpoid (1n)
37
what is syngamy?
occurs when two haploid (1n) gametes fuse
38
what does syn mean
together
39
what does gam mean?
gamete
40
what does syngamy form?
- forms diploid (2n) zygote (fertilized egg)
– zygo = twinned/joined
41
In multicellular eukaryotes, which cellular division doe sit use to form a multicellular embryo?
- uses mitotic cell divison
42
What does the further growth of the embryo lead to?
- it leads to morphological different level stages.
**only some taxa have larvae
43
what does larvae lead to?
- it leads to a reproductively mature adult
44
when does sexual reproduction occur?
- occurs when two parents
produce offspring with novel combinations of genes
from both parents
45
what are examples that ARE NOT sex?
- binary fission and duplication via mitosis
46
what does sex require?
- meiosis* (meiosis* and subsequent fusion of
haploid nuclei from different parents) and subsequent fusion of
haploid nuclei from different parents
47
what is the most common for a non-monophyletic group?
- protists
- they are mostly unicellular eukaryotes that are not
plants, fungi or animals
- animals, fungi and plants area each closely related to a different
protist group
- the old
Kingdom Protista
was paraphyletic (as there are many different clades of protists)
48
Can protsist species bephotoautotrophic,
heterotrophic and
mixotrophic?
yes
49
what is a mixotrophic?
- are both photoautotrophic and
heterotrophic
50
what do single-celled protists have to exist as?
- have to exist as
complete organisms unto
themselves
– internal cellular structure much
more complex than for cells from
multicellular organisms
51
what are selected groups?
groups of protists?
52
Do some protists lack mitochindria?
yes
53
what are diplomonads?
- originally thought to be
ancient eukaryotic lineages that evolved before the acquisition of
endosymbiotic bacteria that evolved into mitochondria
54
Are there still mitochindairal genes present in diplomonads?
- yes
- in some species in these groups, very
tiny nonfunctional mitochondrial remnants
(mitosomes) are present in the cell
- suggests that these protists ancestrally had
regular mitochondria but lost them during
subsequent evolution
– these taxa are all found in anaerobic (oxygenfree) habitats, including guts of animals
– mitochondria are aerobic, and hence they
would not function in these habitats
55
Define the structure of a diplomonad?
- they have multiple flagella and two seperate nuclei.
-diplo= double, two folded.
- has obvious mitosomes (double-membrane bound organelles found in some unicellular eukaryotes,)
56
what is the genus of diplomonad?
- Giardia which infects the human intestine and causes dramatic diarrhea
57
Can non-human mammals be infected by Giardia?
yes,
- it causes beaver fever
is a parasitic infection of the digestive system. Symptoms include severe abdominal discomfort and diarrhea, but some people have no symptoms
58
what are apicomplexans?
- they are parasites of animals
59
what is the structure of Apicomplexans?
- complex of organelles for
penetrating host tissues at apex of cell
- organelles have 4 membranes and
cyanobacterial DNA; this is strong
evidence of secondary
endosymbiosis
60
How many host species do apicomplexans require?
- require 2 or more
host species to complete their life cycles
61
what is plasmodium?
- parasites that
causes malaria, need both
mosquitoes and vertebrates as hosts
(humans are hosts for four
Plasmodium spp.)
- Plasmodium spends part of its life
in blood-feeding flies and part in
vertebrates
62
what are ciliates?
-they have many cilia which names them ciliates
63
what does a cilia do?
- used for locomotion and for capturing food
- many used cilia as their legs to be active and move
64
what do many free-living species feed on bacteria
and smaller protists by?
phagocytosis (cellular eating)
phag = eat and cyto=cell
65
how to ciliates reproduce?
- reproduce asexually by
binary fission, but sometimes engage in a
form of sexual reproduction called
conjugation
66
what is conjugation?
- transfer of plasmids from one ciliate to another
67
what is a paramecium?
- swims in fresh water by beating its thousands of cilia, and feeds on smaller microorganisms such as bacteria and algae
68
what is an amoebas?
- it is a common name for referring to linages of protists that move by extending blunt lobes called pseudopodia.
69
what is a pseudopodia?
- temporary projections of the cytoplasm of the cell.
- they help in feeding the amoeba.
70
what process do amoebas use to eat food?
- they use phagocytosis to eat food and engulf particles.
71
what does pseudo mean?
- false
72
what dos pod mean?
foot
73
what does cyto mean?
cell
74
what is an Amorbozoans?
- it is a clade of amoebas, and maybe is related to fungi and Animalia
75
what are the three different groups of Amoebozoans?
1. solitary amoebas
2. plasmodial slime molds
3. cellular slime molds.
76
what is a solitary amoeba?
- are amorphous single-celled protists with lobe-shaped pseudopodia
- mainly predators of bacteria and smaller
protists
77
what is a plasmodial slime molds?
- start out with a single
nucleus but then undergo repeated mitosis without cell
division
- they become a single giant supercell with free-flowing cytoplasm and nuclei that hunts bacteria on the forest floor.
78
what is cellular slime molds?
- they start as a single-cell body
- when food is limited the adjacent cells get together but maintain separate cell membranes.
- the slug will migrate to. high spot and many cells form a stalk.
- many cells climb up the stalk and develop a
hard coat that allows them to withstand drying
- they disperse in the wind and somewhere wet on land.
79
what are cellular slime molds studied by?
- by those interested in how cooperation
and self-sacrifice can evolve
80
what is algae?
- photoautotrophic eukaryotes that are not
members of the Kingdom Plantae
- they are NOT monophyletic
- many are single celled and others are multicellular and large.
81
what is brown algae?
- it is multicellular and large
82
what is green algae?
- has bright green pigments visible in chloroplasts.
- chloro= green
- more than 7000 species live in freshwater.
- other stay in damp soil, snow or within other eukaryotes.
- they range in size from single-celled to multicellular. which can be qualified as a. seaweed
83
what are the two groups that green algae is divided in?
1. chlorophytes
2. Charophytes (multicellular and morphologically complex)
a. thought to sister taxa to plants
84
what are sedimentary rocks?
- formed from ‘skeletons’ of
marine protists
85
how much is carbon fixation and oxygen production apart of photosyntheisis in algae?
-30% of annual photosynthesis is done by algae
86
what do prostsits cause?
- diseases of plants, wildlife, livestock and
humans (malaria)
- accidental consumption of protists in food can
cause sickness (shellfish poisoning)
-some macroalgae deliberately eaten by humans, like seaweed in sushi.
