The evolution of animals Flashcards

1
Q

What are the features of animals?

A
  • multicellular
  • heterotrophic
  • no cell walls
  • often mobile
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2
Q

Of all the single-celled organisms known to exist, which organism is the most closely related to multicellular organisms?

A

Choanoflagellates

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3
Q

When are geological time scales used?

A

Used to show when major events occurred and the effects this had on life on earth

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4
Q

Why might a fossil record be incomplete?

A

Because many soft bodied organisms do not fossilize easily.

  • can be consumed by other animals
  • not every part can be preserved
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5
Q

Why did arthropods develop an exoskeleton?

A

for protection, structural support and thrived

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6
Q

Which characteristics gave the arthropods advantages ?

A

Jointed appendages allowed arthropods to have much greater flexibility and range of movement. Advantages of having a hard outer layer are protection, water retention, structural support (particularly on land), and counterforce for attachment and contraction of muscles

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7
Q

What advantages does an external shell give over an exoskeleton?

A

external shell: doesn’t need to be used to movement so much thicker and more protection
exoskeleton: less thicker, but able to move and flexible, but still protection

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8
Q

What advantages does having a jaw provide?

A
  • ability to use new resources
  • chewing
  • biting
  • adaptive immune system evolved in jawed vertebrates due to the evolution of jaws
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9
Q

Two major groups of fish:

A

Cartilaginous fish and bony fish

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10
Q

What are the two major groups of the bony fish?

A
  1. the lobe-finned fish with bones in their fleshy fins

2. The ray-finned fish

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11
Q

What did the lobe-finned fish give rise to?

A
  • amphibians
  • reptiles
  • birds
  • mammals
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12
Q

What did the ray-finned fish give rise to?

A

most fish species living today

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13
Q

What did tetrapods have?

A

they had primitive lungs and lobed fins/limbs

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14
Q

Name 6 adaptations to terrestrial life.

A
  • temperature changes
  • air breathing
  • structural support
  • dehydration
  • reproduction
  • UV radiation
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15
Q

What do amphibians have?

A
  • moist skin
  • simple lungs
  • non-amniotic eggs that have to be kept moist
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16
Q

Why do amphibians require less food?

A

Because they are cold-blooded

17
Q

What does a layer of keratin do for reptiles?

A

A layer of keratin forms scales to waterproof

the skin

18
Q

What does the eggs of reptiles have?

A
  • amniotic membrane and soft shell
19
Q

What are sautopsids?

A

Include all the modern reptiles, plus the dinosaurs and birds

20
Q

What are the features of dinosaurs?

A
  • laid shelled eggs
  • some cared for their young
  • warm-blooded altho reptiles
  • may have required a high metabolism to support size and level of activity
  • blood flow through bones, bone growth patterns support warm-blood
  • lived on land
21
Q

What were the dinosaurs that lived in water?

A

Ichthyosaurs

22
Q

Two groups of dinosaurs:

A

lizard-hipped and bird-hipped

23
Q

What happened when a meteorite hit earth?

A

It caused volcanic activity and climate change. the earth was dry and hot and large organisms didn’t have enough food to survive, so small organisms survived.

24
Q

What are the features of birds?

A
 Feathers
 Hollow bones
 Elongated metacarpals
 Wishbone
 Sternal keel
 Air sacs as well as lungs
 Only one of some organs
to save weight
 Hard shelled eggs
 Beak made from keratin
25
Q

Where did birds evolve from?

A

From the therapod dinosaurs. the feathers were probably scales for warmth.

26
Q

What is an archaeopteryx?

A

Archaeopteryx is the most famous of the feathered

dinosaurs

27
Q

Features of archaeopteryx:

A
Reptilian features
 Toothed ‘beak’
 Wing claw
 Long tail containing
vertebrae
 No sternal keel

Avian features
 Airfoil wing with contour
feathers

28
Q

Features of mammals: (monotremes)

A
Features of mammals:
 Fur (made from keratin)
 Warm blooded
 Live young (except monotremes)
 Suckle young with milk, produce milk
29
Q

What were mammals able to do?

A

Mammals were able to adapt and evolve to suit virtually every climate on the planet.

30
Q

What was an advantage of body temperature in mammals?

A
  • maintain body temp to live in both hot and cold areas

- fur = insulator

31
Q

What kind of teeth do mammals have?

A

They ahve highly adapted teeth for specific diets, allowing them to eat a wide variety of foods

32
Q

What are three branches?

A
  • monotremes
  • marsupials
  • placentals
33
Q

What are the features of marsupials?

A
  • live young
  • ## pouch for baby