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Ecology and diversity > Lecture 9- Animal origins and the evolution of body plans I > Flashcards

Lecture 9- Animal origins and the evolution of body plans I Flashcards

1
Q

What traits distinguish animals?

A
  • All multicellular (undergo development from a single cell)
  • All heterotrophs, use internal digestion processes
  • Most move- specialized muscle tissues
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2
Q

What supports the theory that animals are monophyletic?

A

Gene sequences and morphology:

Similar organization and function of Hox genes

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3
Q

What do hox genes do?

A

Control body plan

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4
Q

Why can’t syanomorphies be used to infer relationships?

A

Because all animals have them

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5
Q

What are two other syanomorphies of animals?

A
  • Unique cell junctions

- Common set of extracellular matrix molecules

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6
Q

What are the unique cell junctions in animals?

A

Tight junctions, desmosomes, gap junctions

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7
Q

What are some of the common extracellular matrix molecules in animals?

A

Collagen, proteoglycans

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8
Q

Why don’t some animals have traits that are syanpomorphies?

A

They were lost during their development

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9
Q

What was the most likely ancestor to the animal clade?

A

Colonial flagellated protist

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10
Q

How did animals first begin to evolve from a colonial flagellated protist?

A

Functional specialization of cells in the colony arose (e.g. movement, nutrition, reproduction), cells continued to differentiate

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11
Q

How was coordination among the original colonial flagellated protists from which the animal clade arose improved?

A

Regulatory molecules to control gene differentiation and migration of cells, leading to larger, more complex animals

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12
Q

How are evolutionary relationships within the animal clade studied?

A

Using differences in derived traits

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13
Q

What are the three main groups that all animals belong to?

A

Sponges, diploblastic animals, bilaterians

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14
Q

What two groups are bilaterians divided into?

A

Protostomes and deuterostomes

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15
Q

How are patterns of embryonic development used to study evolutionary relationships?

A

Cleavage patterns distinguish some animal groups

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16
Q

What are cleavage patterns?

A

The first few divisions of the zygote

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17
Q

How is the division pattern of a zygote influenced?

A

Configuration of the yolk

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18
Q

What does cleavage do?

A

Increases number of cells and nuclear mass

Not cytoplasmic mass

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19
Q

What are the cells derived from cleavage called?

A

Blastomeres

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20
Q

What type of cleavage is seen in sea urchins and other echinoderms?

A

Complete radial cleavage

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21
Q

What is the ancestral condition of cleavage for eumetazoans?

A

Complete radial cleavage

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22
Q

What group of animals have spiral cleavage?

A

Lophotrochozoans

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23
Q

What is spiral cleavage derived from?

A

radial cleavage

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24
Q

Name two organisms in which spiral cleavage can be seen.

A

Clams

Earthworms

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25
Q

Complete cleavage is also called…

A

Hobloblastic cleavage

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26
Q

What is incomplete cleavage called?

A

Meroblastic cleavage

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27
Q

In what animals is meroblastic cleavage seen and why?

A

Reptiles- due to presence of large yolk

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28
Q

What are eumetazoa?

A

All animals except sponges

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29
Q

What are lophotrochozoans with spiral cleavage sometimes referred to as?

A

Spiralians

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30
Q

What happens during early development of most animals?

A

Distinct layers of cells form

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31
Q

What happens to the distinct layers of cell that form during early embryo development?

A

They differentiate into specific organs and organ systems as development continues

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32
Q

What are embryos with two cell layers called?

A

Diploblastic

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33
Q

What two cell layers do diploblastic organisms have?

A

Outer ecoderm

Inner endoderm

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34
Q

What cell layers do triploblastic organisms have?

A

Outer ecoderm
Inner endoderm
Middle mesoderm

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35
Q

What is the ancestral condition of cell layers?

A

Diploblastic

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36
Q

What animals show the ancestral condition of cell layers?

A

Ctenophores and cnidarians (paraphyletic)

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37
Q

What happens during early development in many animals?

A

Gastulation

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38
Q

What is gastrulation?

A

A hollow ball one cell thick indents to form a cup shaped structure

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39
Q

What is the opening of the cavity formed by an indentation of the hollow ball formed during early development called?

A

The blastopore

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40
Q

In what animals does the blastopore develop into a mouth first, with the anus forming later?

A

Protostomes

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41
Q

What is the ancestral condition for blastopore development?

A

Deuterostomes

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42
Q

What are the three major clades of deuterostomes?

A

Chordates
Hemichordates
Echinoderms

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43
Q

What type of cleavage is seen in most deuterostomes?

A

Indeterminate cleavage

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44
Q

What is the body plan of an animal

A

The general structure, arrangement and integrated functioning of an animal

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45
Q

What 4 key features make up an animal body plan?

A

Symmetry of body
Structure of body cavity
Segmentation of body
External appendages

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46
Q

What governs the development of an animals body plan?

A

Regulatory genes

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47
Q

What does symmetry describe?

A

The overall shape of an animal

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48
Q

What animals are asymmetrical?

A

Sponges

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49
Q

What is the simplest form of symmetry?

A

Spherical symmetry- body parts radiate out of a central point

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50
Q

Where is spherical symmetry seen?

A

Many unicellular protists

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51
Q

What is radial symmetry?

A

When there is one main axis around which body parts are arranged

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52
Q

What two animal groups are composed mainly of radially symmetrical animals?

A

Ctenophores

Cnidarians

53
Q

How are most radially symmetrical animals modified?

A

So that fewer planes can divide them into idential halves

54
Q

Give examples of radial symmetry that has been modified.

A

Starfish

Sand dollars

55
Q

How do most radially symmetrical animals move?

A

Either sessile

or move equally well in all directions, slowly.

56
Q

What is bilateral symmetry a characteristic of?

A

Animals that move in one direction

57
Q

What is bilateral symmetry?

A

Animals that can be divided into mirror images by a single plan passing through the midline of its body

58
Q

What two planes does a plane at right angles to the midline divide the body into in bilaterally symmetrical animals?

A 
The dorsal (back)
Ventral (mouth and belly)
59
Q

From what point to what point does the plane that divides bilaterally symmetrical animals run?

A

From the anterior to posterior

60
Q

What is bilaterally symmetry associated with?

A

Cephalization

61
Q

What is cephalization?

A

The concentration of sensory organs and nervous tissues in a head at the anterior end of the animal

62
Q

What has cephalization been evolutionary favoured?

A

The anterior end of a bilaterally symmetrical animal typically encounters new environments first

63
Q

What three types can an animal be divided into based on the structure of its internal, fluid filled body cavity?

A

Acoelomate
psuedocoelomate
coelomate

64
Q

What does the structure of an animals body cavity strongly influence?

A

The way it can move

65
Q

Give an example of an acoelomate animal.

A

Flatworm

66
Q

What are acoelomate animals?

A

Animals which lack an enclosed, fluid-filled body cavity

67
Q

What do acoelomate animals have instead of a body cavity?

A

Space between gut and muscular body wall is filled with masses of cells called mesenchyme

68
Q

What tissue layer is the gut derived from?

A

The endoderm

69
Q

What tissue layer is the muscular body wall derived from?

A

The mesoderm

70
Q

How do acoelomate animals typically move?

A

By beating cilia

71
Q

What do psuedocoelomate animals have?

A

A body cavity called a psuedocoel

72
Q

What is a psuedocoel?

A

A fluid filled space in which many internal organs are suspended

73
Q

What is the psuedocoel enclosed by?

A

Muscles (medoderm) only on the outside

No inner layer of mesoderm surrounding internal organs

74
Q

What do coelomate animals have?

A

A coelom

75
Q

What is a coelom?

A

A fluid filled cavity that develops within the mesoderm

76
Q

What is the coelom lined with?

A

A layer of muscular tissue called peritoneum, which also surrounds internal organs

77
Q

What do a coelomate animal have that a psuedocoelomate animal does not?

A

Better control over the movement of fluids in its body cavity

78
Q

What do body cavities of many animals function as?

A

A hydrostatic skeleton

79
Q

How do body cavities function as a hydrostatic skeleton?

A

Fluids are relatively in-compressible
Muscles surrounding fluid contracts, they move to another part of the cavity
Fluid squeezed to one region makes it expand to move body parts

80
Q

What type of muscles do animals have that gives them better control over their body?

A 
circular muscles (encircling body cavity)
Longitudinal muscles (running along length of body)
81
Q

What do most animals have to provide protection and facilitate movement?

A

Skeletons

82
Q

What is attached to skeletons?

A

muscles

83
Q

What does segmentation do?

A

Facilitates the specialization of different body regions,
alter body shape in complex ways
control complex movements precisely

84
Q

What do muscles do when an animal is segmented?

A

Muscles in each segment can change the shape of that segment independently of the others

85
Q

What only occurs in few animals?

A

Complete segmentation

86
Q

What does even partly segmented compartments allow for?

A

Better control of movement

87
Q

Give an example of an animal with an evenly segmented body plan.

A

Hermodice carunculata

marine fireworm

88
Q

What type of animal does the Hermodice carunculata belong to?

A

Annelid

89
Q

What appendages does the marine fireworm have?

A

Simple brushes (setae)

90
Q

What is the function of setae in the marine fireworm?

A

Mainly protection- they contain noxious toxin

91
Q

Give an example of an animal which has segments with different modifications.

A

Orconectes williamsii

92
Q

How did segmentation evolve?

A

Independently several times in both protostomes and deuterostomes

93
Q

In what animals is segments not visible externally?

A

Vertebrates, where vertabrae are segmented internally

94
Q

What led to the dramatic evolutionary radiation of arthropods?

A

Changes in segmented body plan (including muscles attached to external skeletons) and the variety of appendages

95
Q

What do appendages do?

A

Enhance locomotion

96
Q

What does locomotion enable?

A

Obtain food, avoid predators, find mates

97
Q

What appendages do sessile sea anemones have and why?

A

Larval stages with cilia to swim- increase chances of finding suitable habitat to settle

98
Q

What do many echinoderms have?

A

Tube feet

99
Q

Give examples of animals with tube feet.

A

Sea urchins, sea stars

100
Q

What do tube feet allow echinoderms to do?

A

Move slowly across substratum

101
Q

What do limbs allow?

A

Highly controlled, rapid movement

102
Q

In what two animal groups can jointed limbs be seen?

A

Arthropods

Vertebrates

103
Q

What was a prominent factor in the evolutionary success of arthropods and vertebrates?

A

Jointed limbs

104
Q

How were limbs modified into wings?

A

In several independent instances among arthropod insects, pterosaurs, birds and bats

105
Q

What has the need to locate food favored?

A

Evolution of sensory structures to provide detailed info. on environment
Nervous systems that receive/process/coordinate info

106
Q

What are the 5 broad categories of feeding strategies?

A 
Filter feeders
Herbivores
Predators
Parasites
Detritivores
107
Q

What is required to be expended to obtain food?

A

Energy

108
Q

How do filter feeders obtain food?

A

Some kind of straining device filters food from the environment

109
Q

What do air and water contain?

A

Small organisms/ organic molecules that are potential food

110
Q

How do sessile aquatic animals obtain their food through filter feeding?

A

Water currents bring prey

111
Q

Give an example of a motile filter feeder?

A

Phoenicopterus ruber

Flamingo

112
Q

Explain how a flamingo feeds.

A

Serrated beak filters small organisms out of a muddy mixture it picks up as it wades through shallow water

113
Q

How do some sessile filter feeders expend energy?

A

By moving water past food capturing devices

114
Q

Give an example of a sessile filter feeder moving water past food capturing devices

A

Sponges bring water to their bodies by beating flagella of specialized feeding cells called choanocytes

115
Q

What are choanoflagellates and the animals most closely related to what clade does this make up?

A

Fungi and choanoflagellated protists

Opisthokonts

116
Q

How are herbivores different to carnivores, other than what they eat?

A

Herbivores often feed on plants without killing them

117
Q

What is an advantage of herbivory?

A

Animals do not need to expend energy capturing and subduing plants

118
Q

What is a disadvantage of herbivory?

A

Plants can be difficult to digest- many different kinds of tissues, fibrous, chemicals that need to be detoxified

119
Q

What herbivores feed on the single plant, the silky willow?

A

Tiger swallowtail butterfly larva
Adult leaf beetle
Willow sawfly larvae
Leaf beetle larvae

120
Q

What adaptations to predators have to make them able to capture and subdue relatively large animals?

A

Sensitive sensory organs
Sharp teeth/claws
toxins

121
Q

How do cnidarians capture and subdue prey?

A

toxins- tentacles are covered with specialized cells containing stinging organelles called nematocysts which inject toxin into prey

122
Q

Give an example of a predator whose teeth are adapted to its omnivorous diet.

A

Ursus arctos

Kodiak brown bear

123
Q

Give an example of a predator whose appendages and beak are adapted to life as a predator.

A

Bald eagle

124
Q

What is the function of sylets and spines on a nematocyst?

A

To anchor it to its prey

125
Q

Give an example of an animal that has nematocysts

A

Physalia physalia

Portuguese man-of-war

126
Q

What are parasites that live inside their host called?

A

Endoparasites

127
Q

What are endoparasites usually like?

A 
morphologically simple
function without digestive system
128
Q

What are parasites that live outside of their host called?

A

Ectoparasites

129
Q

Give an example of two ectoparasites of humans.

A

Fleas

Ticks

Ecology and diversity (17 decks)

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