Chapter 32: Animal Diversity and the Evolution of Body Plans Flashcards
1
Q
What are the 9 general features of Animals?
A
- Heterotrophy
- Multicellularity
- No cell walls
- Active movement
- Diversity of form
- Diversity of habitat
- Sexual reproduction
- Embryonic development
- Tissues
2
Q
Define Heterotrophy
A
Heterotrophy: Obtain energy and organic molecules by ingesting other organisms
3
Q
Define embryonic development
A
Zygote first undergoes a series of mitotic divisions called cleavage, which produces a ball of cells called a blastula.
4
Q
What are the types of heterotrophs?
A
- Herbivores
- Carnivores
- Omnivores
- Detritivores
5
Q
The herbivores consume _______
A
Autotrophs
6
Q
The carnivores consume _______
A
Heterotrophs
7
Q
The omnivores consume _______
A
Both Autotrophs & Heterotrophs
8
Q
The detritivores consume _______
A
Decomposing organisms
9
Q
DNA data has been used to build _______
A
Phylogenies (history tree)
10
Q
Phylogenies confirm that animals are _______
A
monophyletic (closely related)
11
Q
What are the two types and their definition of animal movement?
A
- Sessile: Animals that cannot move from place to place
- Sedentary: Animals that move slowly or rarely
12
Q
Define phyla
A
Phyla: Primary grouping consisting of animals constructed on a similar general plan and thought to be evolutionary related
12
Q
Define phyla
A
Phyla: Primary grouping consisting of animals constructed on a similar general plan and thought to be evolutionary related
13
Q
What are the five key innovations of animal evolution?
A
- Symmetry
- Tissues
- Body cavity
- Patterns of development
- Segmentation
14
Q
Cells of most animals are organized into _______ and _______ units called _______.
A
structural, functional, tissues
15
Q
What is the cycle of the blastula?
A
Blastula folds inward => form a hollow sac with an opening at one end called BLASTOPORE
16
Q
Evolution of symmetry
A
◾Sponges lack any definite symmetry.
◾Virtually all other animals have a symmetry defined along an imaginary axis drawn through the animal’s body.
17
Q
What are the two types of symmetry?
A
- Radial symmetry
- Bilateral symmetry
18
Q
What is radial symmetry?
A
Body parts arranged around central axis
Can be divided into two equal halves by any plane that passes through the center
19
Q
What is bilateral symmetry?
A
A body has right and left halves that are mirror image
Only SAGITTAL plane bisects the animal into 2 equal halves
20
Q
What are the advantages of a BILATERAL symmetry?
A
Cephalization and Directional movement
21
Q
Define CEPHALIZATION
A
Evolution of a definite brain area
22
Q
Zygotes are _______
A
Totipotent
23
Q
Define TOTIPOTENT
A
Can give rise to all other body cells
24
With embryo development comes ...
Cells specialization
25
The process of _______ _______ is _______ except in _______
Cell specialization, irreversible, sponges
26
What are the simplest animals?
Sponges
27
What is NOT present in the simplest animals?
Defined tissues and organs are not present in sponges
28
Sponges have the ability to ...
disaggregate and aggregate their cells
29
All animals other than sponges have ...
Distinct and well-defined tissues
Irreversible differentiation for most cell types
30
Define triploblastic
Animals that have embryos produce 3 germ layers
31
What are the 3 germ layers from the inside to the outside in a triploblastic?
a) Inner endoderm (digestive organs and intestines)
b) Middle mesoderm (skeleton and muscles)
c) Outer ectoderm (body coverings and nervous system)
32
What is the mesoderm?
Skeleton and muscles
33
What is the endoderm?
digestive organs and intestines
34
What is the ectoderm?
body coverings and nervous system
35
What type of symmetry do triploblastic animals have?
Bilateral symmetry
36
What type of cavities are the cnidarians? and what does it mean?
They are diploblastic <=> Have an endoderm and an ectoderm
37
Do sponges have germ layers?
NO
38
Define: Body cavity
Body cavity: space surrounded by mesoderm tissue that is formed during development
39
What are the 3 basic kinds of body plans?
1. Acoelomates
2. Pseudocoelomates
3. Coelomates
40
In Acoelomates:
No body cavity
41
In pseudocoelomates:
Body cavity between mesoderm and endoderm called PSEUDOCOELOM
42
In coelomates:
Body cavity entirely within the mesoderm called COELOM
43
What made the development of advanced organ systems possible?
The body cavity
44
What did coelomates develop? and what is it's function?
Coelomates developed a circulatory system : to flow nutrients and remove waste
45
How many types of circulatory systems exist?
2 - Open and closed
46
Define Open circulatory system
Blood passes from vessels into sinuses, mixes with body fluids and reenters the vessels.
47
Define Closed circulatory system
Blood moves continuously through vessels that are separated from body fluids
48
What is the difference between Open and closed circulatory system?
Open: blood mixes with body fluids, Closed: blood DO NOT mix with body fluids
49
What is the basic pattern of development?
Bilaterian
50
Bilaterian pattern of development steps
Cleavage of the egg forms a hollow ball of cells called the blastula
(that indents to form a two-layer-thick ball with blastopore and archenteron)
51
Blastopore
Opening to outside
52
Archenteron
Primitive body cavity
53
How many groups of Bilaterians exist?
2 - Protostomes and Deuterostomes
54
Define PROTOSTOMES
Protostomes are bilaterians that develop the mouth from or near the blastopore ( Anus if present develops either from blastopore or another region of embryo)
55
Define DEUTEROSTOMES
Deuterostomes are bilaterians that develop the anus first from the blastopore (Mouth develops later from another region of the embryo)
56
Difference between protostomes and deuterostomes:
1) Cleavage pattern of embryonic cells
a) Protostomes => Spiral cleavage (right or left)
b) Deuterostomes => Radial cleavage (top)
57
Spiral cleavage
New cells form to the right or left of previous cells.
58
Radial cleavage
New cells form on top of previous cells.
59
Difference between protostomes and deuterostomes:
2) Development fate of cells
a) Protostomes => Determinate development (cell fate is determined early)
b) Deuterostomes => Indeterminate development (cell fate is not determined until after several divisions)
60
Difference between protostomes and deuterostomes:
3) Formation of the coelom
a) Protostomes => Cells move apart to form the coelom
b) Deuterostomes => Group of cells punch off to form the coelom
61
What are the two advantages of segmentation?
1) Allows redundant organ systems in adults such as occurs in the annelids.
2) Allow for more efficient and flexible movement because each segment can move independently.
62
Multicellular animals are divided into distinct _______
Phyla
63
How many branches are the metazoans (Kingdom Animalia) divided into? and what are they?
2 main branches - Parazoa and Eumetazoa
64
Parazoa
no true tissues - sponges - lack a definite symmetry - monophyletic (most recent common ancestor and all its descendants)
65
Eumetazoa
True tissues - Animals other than sponges - have a definite symmetry - cnidaria and Bilateria
66
Cnidaria
Branch off evolutionary tree BEFORE Bilateria.
They have radial symmetry.
67
Going to Bilateria, how did protostomes and deuterostomes change ?
Phylogeny of protostomes has changed due to molecular data
Phylogeny of deuterostomes has not changed much
68
What previous phylogenies were based on?
The evolution of coelom
69
T/F: All protostomes have coeloms
False - Protostomes are variable
70
T/F: All deuterostomes have coeloms
True
71
Complex bodies are _______ _______
Well defined
72
Define sexual reproduction
fusion of 2 haploid gametes
73
When we are going from zygote to differentiated cells we have a decrease in _______ and an increase in _______
Potency (totipotent => pluripotent => multipotent => differentiated )
cells (tissue => organ => system)
74
T/F: All animals have segmentation
False - some of them have it, some of them not
75
How many groups are protostomes divided into? And what are they?
2 groups - Lophotrochozoans and Ecdysozoans
76
What are the 2 characteristics of lophotrochozoans?
1) Grow by gradual addition to the body mass
2) Have spiral cleavage
77
What is the characteristic of Ecdysozoans?
They molt (undergo ecdysis) (shedding their skin)
NB: Ecdysozoans include the arthropods
78
What groups do deuterostomes include?
Chordates and echinoderms
79
How do deuterostomes divisions differ from protostomes divisions?
1) Deuterostomes consist of fewer phyla and species
2) They are more uniform in many ways, despite great differences
80
Scientists USED to rely on _______ _______ to classify animals.
Body cavities
81
What phylum is within the branch Parazoa?
Porifera (Sponges (most abundant in the deep ocean) )
82
What are the 3 sponge characteristics?
1) Most lack symmetry
2) Various growth forms
3) Cell types ( Truly multicellular - 3 functional layers in a vase-shaped body )
83
What are the various growth forms of sponges?
1) Larval sponges => free-swimming
2) Sessile => adults remain attached
84
What are the characteristics of metazoans?
a) True tissues
b) Distinct layers (endoderm, ectoderm, mesoderm only in bilateral animals)
c) True body symmetry (Radial - Bilateral)
85
Name 2 types of diploblastic.
Cnidarians & Ctenophores
86
Eumetazoa, Phylum Ctenophora:
What are they known as?
Comb jellies, sea walnuts, sea gooseberries
87
Eumetazoa, Phylum Ctenophora:
What are they formed of?
1) 8 comb-like plates of fused cilia that beat in a coordinated fashion
2) 2 tentacles covered with colloblasts that discharge a strong adhesive used to capture prey
NB: Many bioluminescent
88
Eumetazoa, Phylum Ctenophora:
What is their phylogenetic position?
Unclear
89
Eumetazoa, Phylum Ctenophora:
What do they lack?
Nematocysts (venom)
90
Eumetazoa, Phylum Ctenophora:
T/F: Ctenophores are structurally less complex than cnidarians
False - Ctenophores are structurally MORE complex than cnidarians
91
Eumetazoa, Phylum Cnidaria:
T/F: They have distinct tissues and few organs.
False - They have distinct tissues but NO organs (aka no organ systems)
92
Eumetazoa, Phylum Cnidaria:
T/F: They don't have a concentrated nervous system.
True
93
Eumetazoa, Phylum Cnidaria:
What do they have?
1) Latticework of nerve cells
2) Touch gravity light receptors
94
Eumetazoa, Phylum Cnidaria:
How do they catch their prey?
With their UNIQUE venom called nematocytes
95
Eumetazoa, Phylum Cnidaria:
What are the 2 basic body forms of cnidarians? Mention their characteristics
1) Polyps: Cylindrical and sessile
2) Medusae: umbrella-shaped and free living
NB: Many alternate between these two phases.
96
Eumetazoa, Phylum Cnidaria:
What is the body plan of cnidarians formed of?
1) Single opening leading to gastrovascular cavity
2) 2 layers to body wall
97
Eumetazoa, Phylum Cnidaria:
What are the 5 roles of the cnidarian gastrovascular cavity?
1) Site of digestion
2) Most gas exchange
3) Waste Discharge
4) Formation of gametes in many
5) Hydrostatic skeleton ( Provides a rigid structure against which muscles can operate & Gives the animal shape)
98
Eumetazoa, Phylum Cnidaria:
What are their 3 layers?
-Epidermis
Mesoglea (as a glue)
-Gastrodermis
99
Eumetazoa, Phylum Cnidaria:
T/F: Many polyp species build an exoskeleton of chitin or calcium carbonate around themselves. Some build an internal skeleton.
True
100
The Bilateria:
What are their characteristics?
1) Bilateral symmetry
2) Allowed for high level of specialization.
101
The Bilateria:
Into how many clades they are divided? What are they?
2 clades:
1) Protostomes and deuterostomes
2) Acoel Flatworms
102
Define clades
group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants
103
Phylum Acoela:
What were acoel flatworms once considered?
Basal members of the phylum Platyhelminthes.
104
Phylum Acoela:
What are their characteristics?
- Primitive nervous system
- Lack of digestive cavity
105
Phylum Acoela:
What is the consequence of the absence of a digestive cavity?
The mouth leads to a solid digestive syncytium (a mass of cells that have no cell membranes separating them).
106
Try to explain a few points for yourself
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