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Genetics and evolution > Evolution of the major groups of organisms! > Flashcards

Evolution of the major groups of organisms! Flashcards

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1
Q

What are the 2 mechanisms of rigidity in arthropod exoskeletons?

A

Mineralisation
Sclerotisation

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2
Q

Who removed minerals from the major groups of organisms?

A

Haeckel

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3
Q

Who proposed the 5 kingdoms?

A

Whittaker

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4
Q

Who proposed the 3 domains?

A

Woese in the mid 70s

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5
Q

What is it argued that land plants came about through a symbiosis of?

A

Algae
Fungi

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6
Q

Why might plants have evolved from fungi?

A

Pollen tubes are very fungus-like & many cells in plants grow intrusively into tissues, rather like parasitic fungi

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7
Q

What is it more plausible that land plants evolved from?

A

A green algal ancestor alone in the
intertidal zone

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8
Q

What allowed plants to grow big?

A

A vascular system
Lignin deposits

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9
Q

What is the waxy cuticle for?

A

To reduce waterloss

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10
Q

What are seeds?

A

Packet of differentiated cells (embryo) - well provisioned with nutrients for long-distance travel & survival in adverse conditions

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11
Q

What is the current dominant plant group?

A

Angiospermae

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12
Q

What kind of feeders are fungi?

A

Heterotrophs

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13
Q

What kind of feeders are plants?

A

Autotrophs

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14
Q

What animalia were present by the Cambrian period?

A
  • Sponges
  • Brachiopods
  • Comb jellies
  • Jellyfish
  • Molluscs
  • Worms
  • Jointed-limbed animals (arthropods)
  • Other invertebrates
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15
Q

What is the most basal of the truly multicellular animals and how did it come to be?

A

Porifera - sponges
Evolved from single-celled protists
Coloniality led to multicellularity

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16
Q

What germ layer allowed Cnidaria (jellyfish etc) to develop tissue?

A

Endoderm

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17
Q

What do triploblastic animals have?

A

Endoderm
Mesoderm
Ectoderm

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18
Q

What are the 2 groups of triplobasts?

A

Protostomes & Deuterostomes

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19
Q

What is the difference between protostomes and deuterostomes?

A

In protostomes, the blastopore develops into the mouth, while in deuterostomes, it develops into the anus

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20
Q

What is associated with bilateral symmetry?

A

Cephalisation

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21
Q

Describe an annelid body

A

(i) fluid-filled coelom (a secondarily
produced cavity within mesoderm).
(ii) body is segmented (rings: ‘annelus’
= little ring):
segments are separated within by
bulkheads/partitions (septa).
Rings’ muscles + septa improve
mechanical efficiency of peristalsis

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22
Q

What are setae?

A

Bristles e.g. on worm appendages

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23
Q

Give 3 examples of major groups of arthropods

A

Insects
Crustaceans
Arachnids

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24
Q

What is the rigidity in arthropod armour due to in crustacea only?

A

Mineralisation

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25
What is the rigidity in arthropod armour due to in all arhropods including some crustacea?
Sclerotisation
26
What do some researchers deem the last common ancestor of arthropods?
Hallucigenia sparsa, now recognised as the "lobopodian worm" Close relationship to the velvet worm
27
What body plan do all arthropods have in common?
Head Thorax Abdomen
28
Why are insects, spiders, scorpions etc. less restricted to damp living areas than woodlice and crustacea?
Insects, spiders, scorpions all have an exoskeleton hardened by sclerotisation and LIPIDS which gives more protection Woodlice are restricted because the mineralised and sclerotised exoskeleton is good waterproofing but poor in terms of protection
29
What was the Cambrian explosion kick started by according to Parker?
Evolution of the compound eye by Precambrian proto-trilobites
30
What are the repeating units of a compound eye?
Ommatidia
31
What does it mean that silk is ductile?
Can be stretched considerably
32
What organs secrete silk in arthropods?
spinnerets in spiders & salivary glands in insect caterpillars
33
Winglessness in arthropods is usually an adaptation to what kind of lifestyle?
Parasitic
34
What kind of shell do molluscs have?
Calcareous
35
What organ secretes the exoskeleton in molluscs?
The mantle
36
What did the appearance of the molluscs calcareous shell coincide with?
Coincided with trebling of calcium levels in seawater due to tectonic/volcanic activity (in Cambrian)
37
Did the shell stay around in molluscs?
No it was reduced, used for buoyancy, or even lost completely
38
Describe the radula Absolutely horrifying if i ever encounter a squid i will simply pass away
A radula is a tongue-like feeding structure found in most mollusks. An array (a ‘mat’) of horny protuberances (‘teeth’), used to rasp away at algae, leaves Worn / broken teeth are replaced by new ones (moving ‘belt’ of teeth). In addition, a horny beak is used for biting in some groups (cephalopods)
39
What are the 3 kinds of mollusc eye?
(i) a cup containing light-sensitive cells (pinhole eye) e.g. Nautilus (ii) a cup, backed by a mirror (scallop) (iii) a camera-like device (snail, squid)
40
What are echinoderms?
Spiny-skinned animals: sea urchins, starfish, and their allies
41
What kind of symmetry do echinoderms have?
Radial
42
What did the first vertebrates undoubtably evolve from?
A chordate
43
What did the notochord become?
Intervertebral discs
44
What did fish jaws develop from?
Gill arches
45
What was early fish armour made of?
dentine tubercles which eventually formed teeth This is calcified stuff
46
How do bony fish use the swim bladder to adjust buoyancy?
They control the amount of gas in the bladder – releasing gas into / absorbing gas from the bladder’s interior
47
What 2 things did the first crude lung give way to?
One lineage (which gave rise to the land vertebrates) continued to use it as a lung, while in other fish it was developed it into a swim bladder
48
Which bony fishes led to land tetrapods?
Panderichthyids - most likely Marine fishes. Had a flattened head + long tail + 4 lobed fins. Lobed fins used for walking under water, not land
49
What is limb loss in some amphibians associated with?
Swimming and burrowing
50
Which period is known as the age of the reptiles?
Mesozoic
51
What extrinsic factor contributed to reptiles success?
The drier climate, which was bad for amphibians Global warming promoted radiation of reptiles, and killed off some amphibians
52
What 3 intrinsic factors contributed to reptile success?
1) Insemination / fertilisation became internal 2) Coupled with internal fertilisation was the development of the amnion: a membrane enclosing the embryo in liquid. Possessors of amniotic egg less dependent on aquatic habitats for reproduction. Shell protects amnion + embryo + yolk sac. Yolk sac enables development to a more advanced stage of development – improves progeny’s survival chances. 3) Scaly skin (reduces evaporation from body).
53
What did proto-wings enable?
Life Gliding during short duration, low altitude leaps during running Perhaps assisted prey capture / escape from predators
54
What was the first known bird called?
Archaeopteryx Discovered 1800s
55
Where did the ancestral modern birds live?
On water Therefore had webbed feet
56
Is the terrestrial habit of modern birds a primary or secondary development?
Secondary - they lived on water primarily
57
What are synapsids?
Synapsida is a diverse group of tetrapod vertebrates that includes all mammals and their extinct relatives
58
What 3 developments did synapsid reptiles show?
Increasing dental specialisation Greater separation of nasal passage and mouth Legs positioned below body
59
Why was the K-T event good for mammals?
K-T event meant mammals experienced considerable release from competition & from predation by dinosaurs
60
These are just mammal characteristics idk memorise if you want
(i) larger brain cases (ii) complex cheek teeth (iii) single lower jaw-bone (iv) complex ossicles in ear (v) larger ilium in pelvis (vi) body hair (vii) mammary (milk) glands + (in marsupials & placentals) fleshy lips for suckling (viii) ‘warm-bloodedness’ (homeothermy) (ix) amniotic condition of egg
61
Are there more extant spp of mammals or reptiles?
Reptiles - 7000 Mammals - 4000
62
What do monotremes do?
Lay shelled eggs
63
What order do humans belong to?
Primates
64
What is the earliest known ape species?
Egyptopithecus Fossil found in Oligocene deposits
65
What is brachiation?
Arm-swinging
66
What was happening globally in the late Miocene?
Climate cooling Therefore decline of forests and movement of apes and monkeys
67
What did hominid fossils show?
Australopithecines - upright locomotion & distinctive human foot.
68
What is the earliest distinct species of true humans?
Homo habilis – which manufactured & used stone tools Or Homo Naledi
69
Which of our ancestors did Homo habilis radiate into?
Homo erectus
70
Describe Homo erectus
* Much larger-bodied & larger-brained (900cc). * 1st evidence of meat-eating coupled with group-hunting. * Sophisticated tools. * 1st hominid to leave Africa – even reaching Asia
71
Homo erectus evolved into the even larger brained what?
H. heidelbergensis
72
Describe H. heidelbergensis
They still had large brows, jutting jaws (= prognathous) & flat faces * Relatively flatter faces of very modern populations appeared 50-60TYBP * Brain size (= 1400cc) was same as today’s humans
73
What did H. sapiens coexist with until the latter became extinct?
Neanderthals
74
Why is it thought that dark skin developed?
primarily to prevent UV-induced breakdown of Vitamin B (folic acid) – a nutrient essential for fertility & foetal development
75
Why do people have different skin colours?
Skin that is too dark prevents enough UVB penetrating the skin for Vitamin D production to occur (Vitamin D is needed to produce strong maternal and foetal bones) * Skin that is too light allows the UVA in sunlight to destroy Vitamin B
76
What is steatopgyia?
Extreme development of the buttocks * Once a widespread trait across Africa, now confined to a few populations such as the Khoisan. * The ability to store large fat amounts is important in very seasonal environments

Genetics and evolution (16 decks)

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