Exam 2 Flashcards
(303 cards)
1
Q
Unlike nonvascular plants, seedless vascular plants
1. can live independently as gametophytes 2. can live in drier environments 3. can move resources more efficiently from shoots to roots 4. all of the above
A
c. can move resources more efficiently from shoots to roots
The main transition is vascularization. In order to live in dry environments, there must be access to moist environments and, in nonvascular plants AND seedless vascular plants, the fertilization of gametophytes is difficult. Pollen evolves at seed plants and allows male gametes to move in dry environment.
2
Q
What is biodiversity?
A
the variability among living organisms from all sources and the ecological complexes of which they are part; includes differences within and among species and ecosystems
3
Q
What is the cell wall in bacteria made of?
A
peptidoglycan
4
Q
What makes up the cell wall in archaea?
A
polysaccharides and proteins
5
Q
What do fimbriae and capsule do in prokaryotes?
A
stick to substrates
6
Q
What do pili do?
A
pulls prokaryotic cells together for conjugation
7
Q
What is conjugation?
A
when prokaryotic cells exchange genetic material
8
Q
What function do flagella serve?
A
mobility
9
Q
What kind of membrane do aerobic prokaryotes have?
A
respiratory membrane, like mitochondria
10
Q
What kind of membranes do photosynthetic prokaryotes have?
A
thylakoid membranes
11
Q
Describe the chromosomes in prokaryotes.
A
circular, have less DNA than eukaryotes
12
Q
What are plasmids?
A
small rings of DNA that replicate independently; much smaller than chromosomes
13
Q
Are plasmids more common in prokaryotes or eukaryotes?
A
prokaryotes
14
Q
How did scientists discover there were 3 domains instead of 2?
A
After sequencing DNA in 1977, analysis of ribosomal RNA indicated that several methanogens were not bacterial. Archaea have more in common with eukaryotes.
15
Q
What are extreme halophiles?
A
archaea that survive in high salt levels
16
Q
What are extreme thermophiles?
A
archaea that survive in high heat levels
17
Q
How do bacteria survive in stressful conditions?
A
By forming endospores
18
Q
What is an endospore?
A
tough structure that contains a copy of bacterial chromosome and is released into the environment; remain dormant until conditions improve
19
Q
Does binary fission lead to diversity?
A
No. It’s a process where prokaryotes clone themselves.
20
Q
- Prokaryotes do not have sexual reproduction, a major source of genetic diversity. How do they evolve so quickly compared to many eukaryotes?
- Prokaryotes have higher rates of mutation than eukaryotes.
- Prokaryotes have shorter generation times than eukaryotes.
- Prokaryotes are evolutionarily older than eukaryotes, so they have more experience adapting.
- All of the above.
A
- Prokaryotes have shorter generation times than eukaryotes.
21
Q
How is genetic diversity generated in prokaryotes?
A
Mutation and recombination
22
Q
What mechanisms allow prokaryotes to introduce diversity?
A
Transformation, Transduction, and Conjugation
23
Q
How does transformation work for prokaryotes?
A
Foreign DNA is transported into cells from the environment. Proteins recognize that the DNA is from a closely related species. The integrated DNA can be integrated into the genome or exist as a plasmid.
24
Q
What are the possible fates of integrated DNA in prokaryotic transformations?
A
The integrated DNA can be integrated into the genome or exist as a plasmid.
25
Describe transduction.
Phage infect bacteria and replicates within the host. New phages may gain fragments of donor cell DNA that are carried from donor to recipient cell. That fragment is inserted into the recipient and recombined into a new genome.
26
How does conjugation in prokaryotes work?
Occurs between 2 different bacterial cells. F plasmid from F+ cell is passed and signals to the other cell to create a mating bridge. During DNA replication, DNA strand breaks off the F plasmid and moves across the mating bridge to the mating cell. Synthesis of DNA replaces the plasmid in the donor cell and the recipient cell synthesizes aa complementary DNA strand. The recipient cell transitions from an F- cell to a recombinant F+ cell.
27
What is an F- cell?
one that lacks an F plasmid
28
- You collect a sample of bacteria from a nearby stream and streak it onto an agar plate. You notice the tone population on the plate is growing very vigorously. A day later, an adjacent population is also growing quickly. You suspect a new gene fro rapid growth has appeared in the second population. If the population lacks an F plasmid and the plate has been treated with an antiviral compound, what mechanism is being used?
1. mutation
2. transformation
3. transduction
4. conjugation
transformation
29
How do the short generation times of prokaryotes contribute to fast evolution?
Allows the accumulation of mutations, leading to opportunities for selection
30
What is horizontal gene transfer and how does it contribute to fast evolution in prokaryotes?
recombination between different species via mating bridges; leads to novel genes
31
How do plasmids contribute to fast evolution in prokaryotes?
Mobile DNA with high genetic variation is useful for adapting to new environments.
32
What are phototrophs?
organisms that receive energy from light
33
What are chemotrophs?
organisms that receive energy from chemicals
34
What are autotrophs?
organisms that use inorganic carbon (CO2)
35
What are heterotrophs?
organisms that use organic carbon (like glucose)
36
What is a mixotroph?
organisms that can use different sources of energy and carbon, depends on environmental conditions
37
- We can combine these terms to describe the nutritional modes of different organisms. For example, a cyanobacteria would be a
1. photoautotroph
2. chemoautotroph
3. photoheterotroph
4. mixotroph
photoautotroph
38
What are decomposers?
heterotrophs that break down dead organic material
The ensuing molecules can be used by other organisms in the environment.
39
List 2 ways prokaryotes are responsible for oxygen production.
Autotrophic cyanobacteria and photosynthesis
40
What is nitrogen fixation?
When cyanobacteria and methanogens (archaea) convert atmospheric nitrogen (N2) to useable nitrogen (NH3)
41
What were the initial divisions of protists?
-
- Protozoa - animal like
- Protophyta - plant like
- Molds - fungus-like
42
Why did scientists change the way protists were initially described?
Because protists are paraphyletic. All protists share common ancestor, but other non-protist organisms also have the ancestor and are excluded.
43
What are some key innovations of eukaryotes?
Diverse protection and support structures, Nuclear envelope, Endosymbiosis, Multicellularity
44
What is the difference between mitochondria and chloroplasts’ history?
Organisms with mitochondria are monophyletic, with a single origin. Not all lineages of protists with chloroplasts are monophyletic
45
What did primary endosymbiosis yield?
red and green algaae
46
What did secondary endosymbiosis yield?
photosynthetic protists
47
The evolution of plastids through secondary endosymbiosis differs from plastids produced through primary endosymbiosis because in secondary endosymbiosis
1. a eukaryote engulfs a prokaryote, leading to a single plastid
2. a eukaryote engulfs a prokaryote
3. a eukaryote engulfs a eukaryote with a plastid, leading to a single plastid
4. a eukaryote with a plastid experiences a mutation that leads to physical changes in the existing plastid
3. a eukaryote engulfs a eukaryote with a plastid, leading to a single plastid
48
What is the evidence for endosymbiosis?
Chloroplasts have 3-4 membranes. Photosynthetic pigments shared by land plants and distantly related protists. Nucleus is now vestigial
49
Why are the majority of eukaryotes unicellular?
because most protists are unicellular
50
Describe plasmodium. How do they protect themselves?
Highly adaptable protist that causes malaria. They mainly live inside host cells. When the body attempts to target it, it causes autoimmune issues.
51
Describe trypanosomes. How do they prevent host immunity?
Highly adaptive protist responsible for Chagas' disease. When immune system begins recognizing foreign protein and starts targeting it, the trypanosomes switch the surface protein so they have to find it again.
52
What are the primary producers?
Green algae and diatoms
53
Describe green algae.
Unicellular or multicellular protists; filamentous. primary producers. Freshwater and marine environments.
54
What is unique about diatoms?
Have a fragile cell wall with silicon dioxide.
55
Explain the global carbon cycle and how protists are involved.
After diatoms bloom and proliferate, their glass bodies sink to the ocean floor. Their carbon is preserved at the ocean floor instead of being released into the atmosphere. Promoting blooms may reduce CO2 emissions.
56
What are dinoflagellates?
Algal bloom protist that can live in freshwater or marine environments. Cause toxic red tides.
57
Describe plants’ phylogeny.
A monophyletic clade of multicellular taxa.
58
What are plants' closest relative? List 5 pieces of evidence.
Charophytes (green algae - protists). Both are photosynthetic, possess chloroplasts with chlorophyll a and b, have protein rings that synthesize cellulose, unique flagellated sperm structure, and formation of phragmoplasts during cell division.
59
When did land plants originate?
470 MYA
60
What are 5 reasons that plants moved from water to land?
- More atmospheric carbon dioxide in the air than in the water; needed for photosynthesis
- More light on land than water
- Lots of nutrients in soil
- Lots of habitat
- Low competition
61
List 6 adaptations plants faced in moving from water to land.
```
Prevention of water loss
UV protection
Access nutrients efficiently
Multicellular organ for gamete production
Embryos with parental resources
Alternation of generations
```
62
How do different plants prevent water loss?
Waxy cuticle that keeps water in leaf surface.
Stomata for gas exchange; prevents water loss when closed.
Desiccation-resistant spores
63
How do plants protect themselves from the sun?
They form flavonoids to provide “sunscreen” to protect their surfaces from sun damage.
64
What allows plants to access land nutrients efficiently?
Mycorrhizae
65
What are mycorrhizae?
symbiotic relationships between fungi and plants
66
How does the gametangia structure benefit plant organs?
Prevents desiccation in land plants
67
Is alternation of generations unique to plants?
No. It's found in some protists and fungi. It evolved independently in plants.
68
- Many adaptations were required for early plants to survive on land. These adaptations
1. are relatively restrictive and have limited the habitats where plants can grow
2. were facilitated by the formation of plastids through secondary endosymbiosis
3. allowed early plants to colonize any available terrestrial habitat
4. are also found in most extant plants, meaning these traits are highly conserved
d. are also found in most extant plants, meaning these traits are highly conserved
69
How are gametes different between plants and animals?
In plants, gametes are formed via mitosis instead of meiosis.
70
What process creates a sporophyte?
mitosis
71
What is a sporophyte, what does it form, and how?
a mature diploid plant individual. Forms spores through meiosis.
72
What process do spores undergo and what do they create?
Mitosis to create gametophyte
73
How does the gametophyte produce gametes?
Through mitosis on the gametangia.
74
- Which life stage(s) is/are haploid?
I. Spores
II. Gametes
III. Zygotes
1. I
2. II
3. I and II
4. II and III
3. I and II
75
- Which life stage(s) is/are formed by meiosis?
```
I. Spores
II. Gametes
III. Zygotes
1. I
2. II
3. I and II
4. II and III
```
1. I
76
- Which life stage(s) is/are formed by mitosis?
I. Spores
II. Gametes
III. Zygotes
1. I
2. II
3. I and II
4. II and III
2. II
77
What process forms zygotes in plants?
fertilization
78
What are bryophytes?
nonvascular plants
79
What are nonvascular plants?
Plants that lack specialized cells that transport water and nutrients. This limits height and size. They lack roots and leaves.
80
Lacking roots, what do bryophytes use as anchors?
rhizoids
81
What is the dominant life stage for bryophytes?
Gametophyte
82
Why do nonvascular plants have to be near water during reproduction?
Sperm travel through water.
83
Sporophytes in nonvascular plants cannot live independently. How does it cope?
Attached to gametophyte, which supplies water and nutrients (although it can be photosynthetic)
84
How are spores dispersed?
via wind
85
- In bryophytes, the gametophyte
1. produces gametes through meiosis
2. is the dominant life stage
3. cannot live independently
4. all of the above
is the dominant life stage
86
- In bryophytes, the sporophyte
1. produces spores through meiosis
2. is a reduced/infrequent life stage
3. cannot live independently
4. all of the above
all of the above
87
When did vascular plants originate?
425 MYA
88
How is the vascular life stage different from the nonvascular life stage?
In nonvascular plants, the gametophyte is dominant and the sporophyte is dependent on it for nutrition. In vascular plants, the sporophyte is dominant life stage. The gametophyte is an independent reduced stage.
89
How do seedless vascular plants differ from bryophytes?
- Larger, independent sporophyte
- Vascular system
- Roots and leaves
90
What did vascularization lead to?
Increased size of plants
91
What is xylem?
water conducting cells with lignin in the cell walls; part of the vascular system of plants
92
What is in the cell walls of xylem?
lignin
93
What is phloem?
distributes sugars, amino acids, and products synthesized by the plant; part of the vascularization system
94
What is lignin?
polymer found in xylem cell walls; provides structural support; helps plants grow tall
95
Derived traits of vascular plants?
Roots
Leaves
Spores
96
What are the benefits of roots for vascular plants?
absorb water and nutrients from soil
97
What are the benefits of leaves for vascular plants?
increased photosynthesis
98
How are seedless vascular plant spores different from seed plants?
Seedless vascular plants are homosporous.
| Seed plants are heterosporous.
99
What does homosporous mean?
They make the same kind of spore. Bisexual gametophytes have organs to make sperm and eggs.
100
What does heterosporous mean?
Male gametophytes make sperm and female gametophytes make eggs.
101
What are the 2 categories of seedless vascular plants?
Lycophytes and Monilophytes
102
What are lycophytes?
club mosses and spike mosses; most ancient rooted lineage of seedless vascular plants
103
What is the Carboniferous?
Period where giant seedless vascular plants converted CO2 to organic carbon, then died.
The microbes that break down cellulose and lignin had not evolved yet. Trees didn’t fully decay, they turned into coal (90% of the coal we use today).
104
When was the Carboniferous?
360-300 MYA
105
What did lycophytes look like during the Carboniferous?
tree-sized
106
- Club mosses are not true mosses, but share this name with some bryophytes due to their similar phenotypes. Without disturbing, dissecting or sequencing these plants, what visual cues would allow you to distinguish a club moss from a true moss?
1. A club moss will have leaves and true moss will not
2. A club moss will be taller than a true moss
3. A club moss will have 2 distinct and independent structures during its life cycle, while a true moss will have only a single structure.
4. all of the above
4. all of the above
107
What are monilophytes?
ferns, horsetail, and whisk ferns; seedless vascular plants common in moist, humid environments
108
What are the 2 categories of seed plants?
Gymnosperms and Angiosperms
109
What happens to alternations of generations in gymnosperms?
Gametophyte occurs within the sporophyte, completely dependent.
110
What are seeds?
embryos with food supplies in a protective coat
111
How do seeds benefit plants?
reproductive structure that can disperse long distances and survive harsh conditions, unlike spores
112
What is pollen?
male gametophyte that will produce the sperm, surrounded by a pollen wall
113
How does the sperm in seed plants differ from bryophytes based on pollen?
does not require water to travel to female gametophyte (unlike mosses and ferns)
114
What does the megasporangia make?
1 megaspore (female gametophyte)
115
What does the microsporangia make?
lots of microspores (male gametophytes)
116
- What is the proximate source of food found in seeds?
1. megasporangium
2. megaspore
3. female gametophyte
4. egg nucleus
3. female gametophyte
Food is haploid, cannot be the megasporangium (which is diploid).
Megaspore undergoes mitosis to become the female gametophyte.
117
What do all gymnosperms have in common?
All are woody.
Have vascular cambium inside.
Have cork cambium outside.
Grow in circumference as they increase in size.
118
What kind of plants are gymnosperms?
conifers, evergreen with small and needlelike leaves
119
Which cambium is inside and which is outside in gymnosperms?
Vascular cambium - inside
| Cork cambium - outside
120
What does the vascular cambium do for gymnosperms?
produces secondary xylem, forming wood
121
What does the cork cambium do?
As cork cells mature and die, they protect the stem.
122
Unlike seedless vascular plants, seed plants
1. can live independently as gametophytes
2. can live in drier environments
3. can move resources more efficiently from shoots to roots
4. all of the above
b. can live in drier environments
The major innovation is seeds and seeds come with pollen, allowing plants to live in drier environments. Seed plants cannot live independently as gametophytes. Both are vascular plants.
123
When did extant seed plants emerge?
360 MYA
124
When did seedless vascular plants become dominant?
During the Carboniferous (360-300 MYA)
125
Why did gymnosperms replace seedless vascular plants for dominance during the Permian?
Drier conditions (creation of pollen)
126
Describe the differences in the gametophyte between nonvascular plants, seedless vascular plants, and seed plants?
Nonvascular plants - dominant
Seedless vascular plants - Reduced, independent; photosynthetic and free living
Seed plants - Reduced (microscopic), depending on surrounding sporophyte tissue for nutrition
127
Describe the sporophyte in nonvascular plants, seedless vascular plants, and seed plants
Nonvascular - Reduced, dependent on the gametophyte for nutrition
Seedless vascular plants - Dominant
Seed plants - Dominants
128
What are the two major innovations of angiosperms?
fruits and flowers
129
What are flowers' benefit to angiosperms?
They provide a more species-specific breeding system.
130
What do sections of the flower all consist of?
modified leaves
131
What are sepals?
base of the flower
132
What are stamens?
male reproductive structures in flowers
133
What are carpals?
female reproductive structures in flowers
134
What are fruits?
Ovules housed within the ovary. As seeds develop, ovary walls thicken and the ovary matures into fruit.
135
What are the two functions of fruit?
aid in seed dispersal and protect seeds
136
What are the 3 derived traits in angiosperm life cycle?
Microspores, Megaspore, and Double Fertilization
137
What are microspores and how many cells are in them?
male gametophytes with 2 cells in angiosperms
138
How do microspores work?
The generative cell forms 2 sperm. The tube cell forms a pollen tube that facilitated movement of sperm to female nucleus.
139
What is the megaspore and how many cells are in it?
female gametophyte with 7 cells in angiosperms
140
How do megaspores work?
1 cell forms the egg. Most other cells become food for the embryo and other cells guide the pollen tube to the egg.
141
How does double fertilization work?
2 sperm are released into the ovule. 1 sperm fertilizes the egg and the other sperm fuses with 2 nuclei in the embryo sac to create an endosperm
in angiosperms
142
How are endosperm created?
during double fertilization, when the 2nd sperm cell fuses with 2 nuclei in the embryo sac
143
What is the ploidy of endosperms?
triploid
144
What is the function of endosperms in angiosperms?
to feed the embryo; also helps signal that fertilization has occurred so seeds and fruits can develop
145
- Differences in life cycles between gymnosperms and angiosperms include
1. Microspores forming male gametophytes and megaspores forming female gametophytes
2. Nutritional provisioning of seeds
3. Sperm fusing with additional nuclei in female gametophyte to form endosperm
4. The formation of a pollen tube to deliver sperm
3. Sperm fusing with additional nuclei in female gametophyte to form endosperm
146
How are animals more efficient than wind at pollination?
Plants that use the wind must produce lots of pollen and hope it ends up where it must. In contrast, animals visit the same plant species.
147
What attracts animal pollinators?
color and scent
148
- Many flowering plant traits are in response to selection by pollinators. Which of the following mechanisms have contributed to the great diversity in flowering plants?
1. Disruptive selection by pollinators leading to speciation of flowering plants
2. Directional selection by pollinators leading to the evolution of many different floral forms
3. Stabilizing selection by pollinators to maintain highly adaptive floral traits
4. All of the above
all of the above
149
Angiosperms are the most diverse and common plants. List the 2 kinds of magnolids.
Monocots and Eudicots
150
What are the differences between monocots and eudicots?
Monocots have 1 leaf as it germinates, as developing embryos.
Eudicots make 2 leaves as developing embryos.
151
What is the basal angiosperm?
water lillies
152
What is unique about eudicots' pollen grains?
Pollen grains have 3 openings.
153
- Which of the following statements about interactions between angiosperms and animals
is correct?
1. Prior to the evolution of flowering plants, there were no interactions between plants
and animals
2. The diversity of flower shape, color and scent is in response to selection by pollinating animals.
3. Interactions
with animals can increase fitness and genetic diversity, but plants must rely on wind to move to new habitats.
4. Fruits
evolved to protect seeds and fruits consumed by animals represent an incidental interaction with negative effects on plants.
b. The diversity of flower shape, color and scent is in response to selection by pollinating animals.
154
Why are fungi complicated with biological species theory?
All can reproduce sexually or asexually, but asexual reproduction makes it complicated to define.
155
Do fungi reproduce sexually or asexually?
can do both
156
Are fungi unicellular or multicellular?
both
157
How are fungi different from protists?
not motile
158
How do fungi acquire nutrients? What is their trophic level?
Heterotrophs that absorb food from their environments.
159
Describe the process of fungi food absorption.
Secrete hydrolytic enzymes that break down food into smaller components. Digestion occurs outside of bodies.
160
How do multicellular fungi use hyphae?
to grow, acquire nutrients, and reproduce
161
What strengthens fungal hyphae's cell walls?
chitin
162
What do hyphae form?
mycelium
163
What are the belowground mycelium functions?
grow and acquire nutrients
164
What do the aboveground mycelium do?
They are structure for reproduction that spread spores, like mushrooms.
165
When fungi reproduce sexually, how do they find each other?
Pheromones help them discover if the other fungus is compatible for mating.
166
What do fungi form when they reproduce sexually?
multi-nucleated haploid cell
167
What is the ploidy of the zygote when the fungi engage in sexual reproduction?
diploid
168
How do fungi reproduce asexually?
Clonal reproduction through budding and spores.
169
Spores are produced sexually and asexually. How are they different?
Asexual reproduction is a product of mitosis.
| Sexual reproduction is a product of meiosis.
170
What do spores do for fungi?
contribute to fungal dispersal
171
- The filamentous structure of fungal mycelia is adaptive because it:
1. keeps individual fungal size relatively small, reducing their overall energy requirements.
2. provides a large surface area that increases nutrient absorption.
3. helps with self-fertilization of fungi, the most common form of sexual reproduction.
4. All of the above
b. provides a large surface area that increases nutrient absorption.
Fungi are some of the largest organisms on the planet. Mycelia help them grow.
Asexual reproduction is through budding or spores, not self-fertilization.
172
Why did we used to believe fungi are more closely related to plants?
because both are nonmotile
173
Fungi are sister taxa to animals. What are the 4 pieces of evidence?
- All animals and fungi are heterotrophs (plants are autotrophs).
- Chitin is used in fungal cell walls and invertebrates (plants use lignin).
- Carbohydrates are stored as glycogen (not starch, like plants).
- DNA evidence
174
When did fungi and animals diverge?
1-1.5 BYA
175
What is surprising about multicellularity in fungi?
It evolved independently in fungi and animals via convergence not homology.
176
Why is Saccaromyces (Baker’s yeast) a model eukaryotic system?
- Shares basic cellular structures with all eukaryotes.
- Many genes and protein functions are conserved across eukaryotes or have known homologues.
- Easy to study in lab (small genome, short generation size, easily manipulated)
177
What are Mycorrhizae?
symbiotic relationship between fungi and 90% plant species
178
What are 2 ways mycorrhizae benefit plants?
Helps increase nutrient uptake
Have hyphae that can find nutrients better, can access nutrients plants can’t access themselves and break them down
179
How do mycorrhizae receive benefits from plants?
Plants provide carbohydrates.
180
- Plants colonized land about 470 million years ago and evidence suggests that
mycorrhizal associations date back to about the same time. In fact, it seems likely that mycorrhizae helped early plants live on land because:
1. early
plants were very large and required high volumes of nutrients
2. early
plants had limited photosynthetic capacity and therefore required additional
nutrients from fungi
3. early plants lacked roots, making it difficult to extract nutrients from the soil
4. All of the above
3. early plants lacked roots, making it difficult to extract nutrients from the soil
181
What are the 2 kinds of mycorrhizal species?
Arbuscular mycorrhizal fungus and ectomycorrhizal fungus
182
Where do the hyphae go in arbuscular mycorrhizal fungi?
penetrate plant root cells
183
Where do hyphae go in ectomycorrhizal fungi?
surround roots
184
What are endophytes and what benefit do they provide?
fungi that live inside of plants to increase defense or stress tolerance
185
Why are fungi necessary for life?
They are key decomposers. They can break down cellulose and lignin.
186
What are the 4 general traits of all animals?
- Multicellular eukaryotes without cell walls
- Heterotrophs that ingest food
- Mobile at some life stage
- Nerves and muscles (except sponges)
187
What are the only animals that don't have nerves and cells? Why?
Sponges because they are basal.
188
- Animals and ALL fungi share the following traits:
I. Nutritional mode (autotroph, heterotroph)
II. Energy storage product
III. Ingest nutrients from the environment
1. I and II
2. I and III
3. II and III
4. I, II, and III
I and II
189
What are general development patterns for animals?
2 haploid gametes are produced by meiosis. They form a diploid zygote that undergoes mitotic division. Then a blastula is created and gastrulation occurs.
190
What is a blastula?
a single layer of cells with a hollow ball inside; a multicellular stage in animal development
191
Describe the gastrulation process.
One end of the embryo folds inward, creating layers. The layers fill the blastocel, producing layers of embryonic tissue that develop into different structures later.
192
List the structures formed during gastrulation.
Ectoderm - outer layer
Endoderm - inner layer
Archentern - pouch
Blastopore - opening
193
What kind of symmetry do the majority of animals have?
bilateral
194
What does bilateral symmetry mean?
Only one plane where they can be cut in half and have mirror images
195
Are bilateral adults mobile or nonmotile?
mobile
196
What controls the development along anterior-posterior axis in bilateral animals?
Hox genes control segmentation, limbs, and sensory organs.
197
What does radially symmetric mean?
Animals that can be divided in many sections and still form mirror images.
198
Are the radially symmetric adults mobile or nonmotile?
They are sessile, or nonmotile. They are fixed in place.
199
What do asymmetric animals look like?
They cannot be divided to produce mirror images.
200
Are asymmetric adults mobile or nonmobile?
They are sessile and nonmobile.
201
When do germ layers form?
during gastrulation
202
What does the ectoderm form?
skin and nervous system
203
What does the endoderm form?
digestive tract
204
What does the mesoderm form?
circulatory system, muscle, bone, and organs in bilaterians
205
Which symmetrical group are the only ones to have mesoderm?
bilaterians
206
Describe coelomate animals.
body cavity is lined on both sides by mesoderm
207
Describe acoelomate animals.
no cavity, just mesoderm inside
208
Describe pseudocoelomate animals.
Cavities are only lined by mesoderm on one side
209
- Mesoderm is only found in bilaterians, a group that appears more recently. What does this suggest?
1. Animals are moving towards increasing physical complexity, one of the goals of evolution.
2. Asymmetric and radially symmetric animals do not require oxygen for cellular respiration
3. Asymmetric and radially symmetric animals rely on diffusion for basic metabolic processes
4. Animals with bilateral symmetry are more evolved than more ancestral animals.
c. Asymmetric and radially symmetric animals rely on diffusion for basic metabolic processes
Animals with body cavities have mesoderm lining them. Body cavities contain organs, allowing cellular respiration to diffuse. Asymmetric and radially symmetric animals don’t have organs.
210
How do protostomes develop?
spiral, determinate cleavage, 8 cell stage
Bilateral, some lack a head.
Mesoderm splits to form coelom and blastopore becomes the mouth.
211
What is the fate of the blastopore in protostomes?
Mouth
212
How do deuterostomes develop?
radial, indeterminate cleavage
Coelom formed from pouches pinched off the endoderm.
Blastopore becomes the anus.
213
How do coeloms form in protostomes?
Mesoderm splits to become coelom.
214
How do coeloms form in deuterostomes?
Endoderm-derived pouches pinch off.
215
What is the fate of the blastopore in deuterostomes?
Anus
216
- In humans, indeterminate cleavage can result in identical twins if cells are separated within the first 12 days of development. If the human embryo splits in two after 12 days, you might predict
I. survival of one half of hte embryo, depending on the plane of division and how developing tissues are split
II. survival of both halves fo the embryo, depending on the plane of division and how developing tissues are split
III. further division of the embryo, leading to more than two identical siblings
1. I
2. III
3. I and II
4. II and III
c. I and II
I. Unequal conjoined twin, one doesn’t survive.
II. Conjoined twin situation.
C would have to happen before 12 days.
217
- Which of the following traits is true for all animals?
1. multicellular heterotrophic eukaryotes
2. 3 tissue layers
3. nerves and muscles
4. all of the above
1. multicellular heterotrophic eukaryotes
218
- Which traits are found in nearly all animals with bilateral symmetry?
1. mobile adults
2. cephalization
3. distinct organ systems
4. all of the above
all of the above
219
When did animals appear in the fossil record?
710 MYA
220
What are animals' closest living relative?
choanoflagellates (protists)
221
What was the first radiation for animals?
Ediacaran biota
222
What was the second radiation for animals?
Cambrian explosion
223
When did animals move to land?
450 MYA
224
When did terrestrial vertebrates evolve?
365 MYA (tetrapods)
225
When did the diversification of mammals occur?
66 MYA - present
226
When was the age of the dinosaurs?
252-66 MYA
227
List the 2 basal invertebrates.
sponges and jellies
228
How many germ layers do most animals have?
3
229
What is the Porifera's symmetry?
asymmetric
230
Describe sponges' mobility.
Mobile as larvae, sessile as adults
231
Do sponges have true tissue?
no
232
How do sponges undergo gas exchange and waste removal?
diffusion
233
How do sponges eat if they're sessile?
They are filter feeders.
234
Describe the symmetry of Cnidarians.
radially symmetric
235
How many germ layers do Cnidarians have?
2
236
Describe the body plan of Cnidarians
Sac with central digestive compartment
237
What are the 2 phenotypes of Cnidarians?
polyps and medusas
238
Are Cnidarians sexual or asexual?
Can have alternate life stages
239
What group do anemones, jellies, and corals belong to?
Cnidarians
240
What 2 traits do all lophotrochozoans share?
protostomes and 3 germ layers
241
How are lophotrochozoans different from other animals?
Some have lophophores and some have trocophore larvae.
242
What are lophophores?
ciliated tentacles for feeding
243
What are platyhelminthes?
flatworms
244
Describe the bodies of platyhelminthes. Do them have coelom?
Dorosoventrally flattened bodies; acoelomate
245
What's unique about the gastrovascular cavities of platyhelminthes?
Only one opening, not complete
246
Do platyhelminthes have circulatory systems?
no
247
What are annelida?
segmented worms
248
Describe the coelom level of annelida.
Coelomates
249
Why are annelida mostly aquatic or in moist terrestrial habitats?
need water for gas exchange
250
Describe mollusca.
Soft bodies, often with calcium carbonate shells; most have separate sexes, some hermaphrodites
251
What kind of shells do mollusca often have?
calcium carbonate
252
Describe the general mollusca body plan.
Mantle that secretes the shell
Viscerala mass containing internal organs.
Some have radula for feeding.
Feet for locomotion
253
What do mantles do for molluscs?
Secrete their shells
254
What do radula do for some molluscs?
They are teeth-like structures for feeding.
255
Describe gastropods. What are their habitats? Do they have radula? Describe their shells. What are their gas exchange mechanisms?
Terrestrial and aquatic habitat; radula present; single spiral shells
Aquatic - Use gills
Terrestrial - Lung like structure with folds of mantle cavity lining
256
What is the gas exchange method for aquatic gastropods (mollusca)?
gills
257
What is the gas exchange method for terrestrial gastropods (mollusca)?
Lung like structure; folds of mantle cavity lining
258
Describe bivalves. What's their symmetry? Do they have radula? Sensory organs? What is the mantle cavity for? Are they motile?
Mollusca with 2 shells for protection
No distinct head
Bilateral
No radula
Some have eyes, but most have no sensory organs
Mantle cavity has gills for feeding and gas exchange
Mostly sedentary
259
How are cephalopods’ body plans organized?
Trunk on top, head in middle, legs underneath
260
Cephalopods are one of the only mollusc marine hunters. List 4 adaptations they have for predation.
Well developed sensory organs
Jet propulsion by water expelled from mantle cavity
Reduced and internal shell
Closed circulatory system
261
- What traits do flatworms share with segmented worms?
1. symmetry
2. body cavity
3. digestive tract
4. all of the above
symmetry
262
- What traits do squids share with bivalves?
1. trophic level (ex. predator, herbivore, decomposer)
2. complex sensory systems
3. ability to escape predation
4. all of the above
c. ability to escape predation
263
What 3 traits do all arthropods have in common?
Segmented body
Exoskeleton
Jointed appendages
264
What are arthropod exoskeletons normally made of?
Chitin and protein or calcium carbonate
265
How do arthropods grow?
molting
266
Describe the sensory organs of arthropods.
Generally well developed; include eyes, olfactory receptors, antennae
267
Describe the coeloms (or lack thereof) of arthropods.
Coelomates with reduced coelom
268
What is a hemocoel? What 2 groups have them?
main body cavity, containing circulatory fluids
| arthropods and molluscs
269
Describe the circulatory system of arthropods.
Open
| Hemolymph is pumped through hemocoel, not blood vessels.
270
How does gas exchange work for aquatic arthropods?
gills
271
How does gas exchange work for terrestrial arthropods?
Trachae tubes are directly connected to the environment.
272
What is the function of trachae? Where are they common?
They are tubes directly connected to the environment. They are for terrestrial arthropods.
273
- Insects are coelomates. However, most species have a reduced coelom and instead house their digestive and respiratory organs in the hemocoel, a body cavity filled with blood. What is the significance of having a hemocoel as a primary body cavity?
1. Insects have no closed blood vessels, so they contain blood in their largest body cavity, which also contains organs.
2. Insects have no blood vessels, so blood must directly contact organs that facilitate nutrient acquisition and gas exchange.
3. Insects have no blood vessels and the hemocoel represents a precursor to closed circulation.
4. A mutation led to a second body cavity, which houses the digestive and respiratoy organs because the coelom is full.
b. Insects have no blood vessels, so blood must directly contact organs that facilitate nutrient acquisition and gas exchange.
274
What are the 3 groups of noninsect arthropods?
Chelicerates
Myriapods
Crustaceans
275
What kind of arthropods are spiders and ticks?
chelicerates
276
What are the defining characteristics of chelicerates (non insect arthropods)?
8 legs or more, 6 pairs of appendages
277
What kind of arthropods are millipedes and centipedes?
Myriapods
278
How many pairs of legs do millipedes have?
2 pairs
279
How many pairs of legs do centipedes have?
1 pair
280
What are the 2 differences between millipedes and centipedes?
Centipedes are poisonous and millipedes aren't.
| Centipedes have 1 set of legs and millipedes have 2.
281
What are 2 unique qualities of crustaceans?
They have specialized appendages.
| They have heavy shells made of calcium carbonate.
282
List the 3 defining features of insects.
6 legs
Flight (not in all, but very common)
Metamorphosis
283
Can all insects fly?
No, but it's very common.
284
What is incomplete metamorphosis?
young look like adults, but smaller; gain traits as they mature like wings
285
What is complete metamorphosis?
larvae distinct in phenotype, diet, and habitat from adults
286
What are the reproductive strategies of insects?
Sexual reproduction is common. Many insects have sexual dimorphism.
Asexual reproduction also occurs. Haploid males from unfertilized eggs can reproduce through mitosis. Females can undergo parthenogenesis.
287
How can male insects asexually reproduce? What kind of male insects can?
Haploid males from unfertilized eggs can reproduce via mitosis.
288
What is parthenogenesis?
cloning; when female insects have eggs that develop into other females asexually
289
What are the 3 benefits of flying for insects?
Dispersal - allows them to move to any habitat
Foraging - can access niches others cannot
Mating can be long distance
290
What is the benefit of diverse mouthparts for insects?
leads to increased access to different kinds of food
291
List 3 ways insects benefit us.
Pollination
Decomposing
Pest control
292
What is the ploidy of megaspores?
haploid
293
What is the ploidy of megasporangia?
diploid
294
What are the only protostomes without heads?
bivalves
295
What are the 2 kinds of bilaterians?
Protostomes and Deuterostomes
296
What is the difference between an F+ donor and an Hfr donor?
The Hfr donor has an F factor integrated into its main chromosome, but the F+ donor does not.
297
Suppose conjugation occurs between an Hfr cell and an F- cell. Although not typical, what would have to occur for the recipient cell to become an Hfr cell?
The entire F factor would have to be incorporated into the recipient cell’s chromosome.
298
What produces sperm in moss?
antheridia
299
What do moss sperm try to reach?
archegonium
300
What is the ploidy of gametophytes?
haploid
301
What is the ploidy of sporophytes?
diploid
302
What is the ploidy of embryos?
diploid
303
What is the ploidy of the megaspore?
haploid
