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Biology 2 > Chapter 27 - Part 1 > Flashcards

Chapter 27 - Part 1 Flashcards

Animal Origins - rise of animal diversity

1
Q

All but the simplest animals have specialized _, _, and _, systems that make them highly effecting eating machines.

A

Muscle
nervous
digestive

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2
Q

Animals life began in the ocean with small, _ _ species about 560 MYA.

A

soft - bodied

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3
Q

How many animal species are there today?

A

8 million species

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4
Q

What are the most basal (base) and simple modern-day animal group?

A

Sponges
Phylum Porifera

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5
Q

What is the earliest group to have diverged from all other animals?

A

Porifera (sponges)

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6
Q

List the characteristics of Sponges:

A
  1. Lack true tissues
  2. all are aquatic, most are marine
  3. sessile (immobile) filter feeders
  4. can be super small or super big
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7
Q

What animal diverged from all other animals after the sponges and list some examples.

A

Cnidarians
Jellies,
sea anemonies

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8
Q

List the characteristics of Cnidarians:

A
  1. Eumetazoans - true animals since they have tissues
  2. all are aquatic, most are marine
  3. Radial body plan (think cutting it like a pizza)
  4. some are mobile (medusa), others are sessile (polyp)
  5. All carnivores with a gastrovascular activity
  6. no brain but have simple muscles and nerves
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9
Q

What is a gastrovascular cavity?

A

one compartment that functions as both mouth and anus, where all digestion occurs. Pre-cursor to a true digestive system.

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10
Q

List some examples of Cnidarians

A
  1. Hydrozoa (colonial polyps)
  2. Scyphozoa (jellyfish)
  3. Anthozoa (sea anemones)
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11
Q

What was the Cambrian explosion?

A

when the diversity of animals increased dramatically 525-535 MYA.

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12
Q

What happened in the Cambrian explosion?

A
  1. the new species were bilaterians
  2. have a complete digestive tract
    3.when ancestors of modern-day chordates and arthropods appear
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13
Q

what are chordates?

A

vertebrates

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14
Q

List the 3 types of symmetry

A
  1. none
  2. radial
  3. bilateral
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15
Q

Why did the rise of bilaterian life-forms coincided with a decline in earlier life forms?

A

the evolution of armor and weapons

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16
Q

List the characteristics of earlier life forms

A
  1. soft bodied
  2. not predatory (grazers, filter feeders or scavengers)
17
Q

What did the new predators emerge with?

A
  1. defensive hard bodies, shells, sharp pines
  2. offensive adaptations - claws, grasping limbs
18
Q

What do majority of bilaterians have?

A

Mobility, nervous system and digestive tracts that made them dangerous feeding machines

19
Q

The Cambrian explosion was huge for the evolution of diverse forms of animals in the __.

20
Q

What characteristics did the animals in the early oceans have?

A
  1. morphology (body form)
  2. ecology (way of life)
  3. taxonomic affiliation (type of animal group)
21
Q

What is a body plan?

A

a particular set of morphological and development traits that are integrated into a functional whole - the living animal

22
Q

What are the 3 important aspects to an animal’s body plan?

A
  1. Symmetry
  2. tissue organization
  3. body cavities
23
Q

The symmetry of an animal fits it __.

24
Q

Why does radial symmetry work for some animals?

A

because they are sessile or planktonic (drifting or weakly swimming) and this allows them to meet their environment equally from all sides

25
Q

Why is bilateral symmetry important for some animals?

A

because they have sensory equipment that is concentrated at the anterior (front) and this enables them to move directionally to fly, swim, crawl, burrowing

26
Q

What are the 3 types of tissue organization in animal body plans?

A
  1. ectoderm
  2. endoderm
  3. mesoderm
27
Q

What is ectoderm?

A

outermost germ layer which gives rise to the outer covering of the animal and the central nervous system.

28
Q

what is endoderm?

A

innermost layer - gives rise to the digestive organs and respiratory organs

29
Q

What is the mesoderm?

A

everything else the in between layer - gives rise to all the other organs between the outer covering of an animal’s digestive tract.

30
Q

list some examples of mesoderm

A

muscles, bones, circulatory system

31
Q

How many germ layers do Porifera have?

A

zero since they have no true tissues

32
Q

how many germ layers do cnidarians have?

A

2
endoderm and ectoderm

33
Q

how many germ layers do Bilaterians have?

34
Q

Having all 3 germ layers is referred to as

A

trioploblastic

35
Q

What do most bilaterians have?

A

a body cavity called a coelom

36
Q

what is a coelom?

A

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

37
Q

where does the coelom develop from?

38
Q

What are the 3 functions of the coelom?

A
  1. cushions organs
  2. hydrostatic skeleton
  3. independent movement
39
Q

what is hydrostatic skeleton?

A

for animals with a soft body, non-compressible fluid against which muscle can work

Biology 2 (16 decks)

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