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Flashcards in 32 Overview of Animal Diversity Deck (92):
1

What are the basic commonly agreed upon facts about animals based on phylogeny?

-All animals share a common ancestor
-Sponges are basal animals
-Eumetazoa is a clade of animals with true tissues
-Most animals belong to the clade bilateria

2

What are the basic features of animals?

-Multicellular
-Heterotrophs
-Eukaryotes
-Tissue that develop from embryonic layers
-Lack cell walls

3

In what organisms is collagen found?

Only animals

4

Define tissue.

A group of cells that have a common structure or function

5

What is the basic process of animal development?

The zygote then undergoes cleavage (mitotic cell divisions without cell growth). Cleavage leads to the formation of a multicellular stage called a blastula, which consists of a hollow ball.

Then gastrulation occurs, during which the layers of embryonic tissues that will develop into adult body parts are produced.

The resulting developmental stage is called a gastrula.

6

What is a larva?

A sexually immature form of an animal that is morphologically distinct from the adult.

This differs from humans where babies grow directly into adults

7

What is it called when larva become adults?

Metamorphosis

8

What is metamorphosis?

When larva become adults

9

What are homeoboxes?

A class of closely related sequences that appear in the regulatory genes of many animals

10

What are hox genes?

A class of specific homeobox genes

11

Do all animals have hox genes?

All do except sponges that have a different type of homeobox genes

12

What organism are animals most closely related to?

Choanoflagelllates (protists)

13

What is a ‘collar cell'

The type of cell that make up the mouth of a sponge. They contain a flagella for filter feeding

14

What is a ‘choanocyte’?

Aka collar cell

The type of cell that make up the mouth of a sponge. They contain a flagella for filter feeding

15

What does ’Ediacaran biota’ refer to?

A group of early animals that are soft-bodied multicellular eukaryotes.

16

What are the hypothesises for the Cambrian explosion?

-Predators acquired novel adaptions and prey acquired new defences-new predator prey relationships selected against certain groups leading to vacant niches.

-Rising oxygen levels

-Origin of Hox genes allowed greater diversity

17

What are fern 'galls'?

Enlarged cavities that fern plants form in response to stimulation by resident insects

18

What is a common response of ferns to insects?

The formation of ‘galls’ which are enlarged cavities that fern plants form in response to stimulation by resident insects.

19

What is the basic shape of an animal called?

Its body plan

20

What is a body plan?

A particular set of morphological and developmental traits that determine the development and thus structure of an animal and

21

What does ’evo-devo’ refer to?

The interface between evolution and development i.e. the idea that changes to homeotic genes affect development

22

What are the basic forms of symmetry?

Radial and bilateral

23

What are the axes of organisms?

Dorsal is top, ventral is bottom.

They have a ‘left’ and a ‘right’ side


Posterior is top, anterior is the bottom

24

What does ’dorsal’ refer to?

The top

25

What does ventral refer to?

The bottom

26

What does posterior refer to?

Top

27

What does anterior refer to?

The bottom

28

What is the top called?

Dorsal

29

What is the bottom called?

Ventral

30

What is the bottom called?

Posterior

31

What is the front end called?

Anterior

32

What is the concentration of brains near the anterior called?

Cephalisation

33

What is cephalisation?

An evolutionary trend towards sensory apparatus i..e the brain begin concentrated at the anterior end of the organism

34

How are organisms grouped based on how they move?

Sessile, planktonic and motile

35

What are organism that do not move called?

Sessile

36

What does ’sessile’ refer to?

An organism that does not move and thus live attached to a substrate

37

What are organisms that float freely called?

They are referred to as planktonic

38

What does ’planktonic’ refer to?

Organisms that float freely or weakly swim For example jellyfish

39

What are organisms that can move called?

Motile

40

What does ’motile’ refer to?

Organisms that can move i.e. mammals

41

What are the basic layers of tissue called?

'Germ layers'

42

What does ’germ layers’ refer to?

The basic layers of tissue i.e. mesoderm, ectoderm

43

What are the basic germ layers?

Endoderm and ectoderm

Most animals also have mesoderm

44

How are organisms grouped based on germ layers?

As diploblastic or as triploblastic

45

What are diploblastic organisms?

Those that have only two germ layers (ectoderm and endoderm)

46

What are triploblastic organisms?

Those that have three germ layers (ectoderm, endoderm and mesoderm)

47

What are organisms that have two germ layers called?

Diploblastic

48

What are organisms that have three germ layers called?

Triploblastic

49

What organisms are diploblastic and what are triploblastic?

Diploblasts include cnidarians i.e. jellies and corals.

All bilaterally symmetrical organisms are triploblastic.

Sponges are neither: they lack true tissues

50

Are sponges diploblastic or triploblastic?

Neither as they lack true tissues

51

Are jellyfish diploblastic or triploblastic?

Diploblastic

52

Are coral diploblastic or triploblastic?

Diploblastic

53

Are insects diploblastic or triploblastic?

Triploblastic

54

Are humans diploblastic or triploblastic?

Triploblastic

55

Are flatworms diploblastic or triploblastic?

Triploblastic

56

What is a body cavity?

A fluid or air filled space located between the digestive tract and outer body wall.

57

What is a grade?

A group whose members share key biological features

58

How does a grade differ from a clade?

Organisms that have similar features due to analogy are still considered to be part of the same grade even if they are only distantly related

59

How are organisms grouped based on their body cavities?

As coelomates, pseudocoelomates or as a coelomates

60

What is a body cavity also called?

A ‘coelom'

61

What does ’coelom’ refer to?

A body cavity i.e. fluid or air filled space located between the digestive tract and outer body wall.

62

What are ‘coelomates’?

Organisms that have a true coelom

63

What are ‘pseudocoelomates’?

Organisms with pseudocoelom

64

What are are a coelomates?

Organisms that have no coelom or psueodcoelom

65

What is the difference between a coelom and a pseudocoelom?

A true coelom is completely surrounded by mesoderm tissue.

In a pseudocoelom there are a set of concentric rings with a layer of mesoderm and a cavity with a digestive tract composed of endoderm in the centre.

Note that in a pseudocoelom the cavity touches the endoderm and hence it is not a true coelom

66

What is an example of a coelomate?

An earthworm

67

What is an example of a pseudocoelomate?

A roundworm

68

What is an example of an acoelomate?

A planarian

69

Based on its body cavity, what is an earthworm?

Coelomate

70

Based on its body cavity, what is a roundworm?

Pseudocoelomate

71

Based on its body cavity, what is an planarian?

Acoelomate

72

How are organisms grouped based on development?

As protostomes or as deuterostomes

73

What are protostomes?

Organisms in which the mouth develops from the blastopore and thus appears before the anus

74

What are deuterostomes?

Organisms in which the mouth develops from the blastopore and thus appears before the mouth

75

What are animals in which the anus develops first called?

Deuterostomes

76

What are animals in which the mouth develops first called?

Protostomes

77

What are some examples of protostomes?

Molluscs and annelids

78

What are some examples of deuterostomes?

Echinoderms and chordates

79

Are molluscs protostomes or deuterostomes?

Protostomes

80

Are annelids protostomes or deuterostomes?

Protostomes

81

Are echinoderms protostomes or deuterostomes?

Deuterostomes

82

Are molluscs chordates or deuterostomes?

Deuterostomes

83

Are molluscs humans or deuterostomes?

Deuterostomes

84

Are sea urchins humans or deuterostomes?

Protostomes

85

What are the basic ways protostomes and deuterostomes differ?

Cleavage, coelom formation and fate of the blastopore.

86

How do protostomes and deuterostomes differ in terms of cleavage?

In general, protostome development begins with spiral, determinate cleavage.

Deuterostome development is characterized by radial, indeterminate cleavage.

87

How do protostomes and deuterostomes differ in terms of coelom formation?

Coelom formation begins in the gastrula stage.

In protostome development, the coelom forms from splits in the mesoderm.

In deuterostome development, the coelom forms from mesodermal outpocketings of the archenteron.

88

How do protostomes and deuterostomes differ in terms of the fate of the blastopore?

In protostome development, the mouth forms from the blastopore.

In deuterostome development, the mouth forms from a secondary opening with the blastopore becoming the anus.

89

What is determinate cleavage?

The fate of each cell is determined early in develop. Thus if a single cell is isolated it can not develop into a full organism

90

What is indeterminate cleavage?

Each cell produced by early cleavage divisions retains the capacity to develop into a complete embryo.

For example, if the cells of a sea urchin embryo are separated at the four-cell stage, each can form a complete larva.

91

Do humans perform determinate or indeterminate cleavage? What is the consequence of this?

Indeterminate cleavage.

This means that when an embryo splits into two each can form an individual in the case of identical twins

92

What concept allows identical twins?

Indeterminate cleavage as the embryo can split into two with each becoming a full organism.