Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

animal biology > radiations and extinctions > Flashcards

radiations and extinctions Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

taxa

A
  • heirarchial divisions of species from Kingdoms to subspecies
  • group of organisms at any heirarchial rank
  • e.g. family or genus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

are smort or long-lived taxa more abundant?

A

short lived taxa are more abundant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the average age of species?

A

1-4 million years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are background extinction rates?

A

number of species that would go extinct over a period of time based on non-anthropogenic (non-human) factors
- currently extinction rates are accelerating
- account for 95% of all extinctions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

why do most organism go extinct?

A
  • biological, climatic or physical changes to the environment
  • multigenerational loss of reproductive fittness
  • habitat attenuation and dissolution
  • interbreeding (e.g. neanderthals interbreeding with homo sapiens caused their extinction)
  • inability to compete with and displace the resident population
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is reproductive fitness?

A

how many offspring can be produced and their ability to reproduce

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

mass extinctions

A
  • 5% of all extinctions
  • when species vanish faster than they are replaced
  • do not tend to be caused by cataclysmic events (e.g. earthquake)
  • stochastic = population cannot recover once zero
  • rapid = tend to occur within the lifespan of species
  • higher survival chances when the geographical distribution is wide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is a radiation?

A
  • sudden loss in organism diversity leads to periods of expansion and diverification -> fill in vacant niches
  • does not always occur due to an extinction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

evolutionary radiation

A
  • increase in taxonomic diversity caused by elevated rates of speciation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what can cause a radiation?

A
  • extinction
  • major transitions
  • ecological specialisation
  • major innovations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

3 steps of ecological theory of adaptive radiation

A
  1. rapid diverisfication or organisms -> to exploit available ecological niches in the district (mutations accumulate)
  2. competition between different forms exploiting ecological niches
  3. specialization results from trade-offs & means that intermediate phenotypes might be selected against
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what can cause adaptive radiations?

A
  • ecological release = population increases when species are freed from limiting environmental factors
  • ecological opportunity = environmnetal conditions allow niche availability, new ecosystems emerge
  • key innovations / major transition
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is adaptive radiation?

A

diversification of a group of organisms where they fill different ecological niches

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

entropy

A
  • measure of how energy is distributed in a system
  • increased entropy = increased disorder
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

2nd law of thermodynamics

A
  • entropy must always increase
  • need to “cheat” this to be able to do things such as metabolism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

local negative entropy

A
  • increasing order
  • achieved as long as the net entropy of a system is increased
  • mini gradual dissipating systems have negative entropy -> osccilate between products and reactants
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

dissipation

A

energy not transferred to useful energy stores
energy wasted / lost to surroundings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

when did only unicellular life exist?

A

3.8 billion - 900 million years ago

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

when did multicellular life forms emerge?

A

600 million years ago

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

how did multicellular organisms emerge?

A
  • from unicellular ancestors
  • under well defined environmental conditions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

key specialisations of multicellular organisms

A
  • cell-cell adhesion
  • cellular specialisations
  • germ-soma seperation
  • alterations of life cycle via unicellular intermediates
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

selected synapamoprhies in animals

A
  • diploid
  • multicellular
  • conserved genes for body plans
  • posses true epithelia
  • develop from a blastula
  • eggs develop from 1 of 4 daughter cells in meoisis 2
  • aerobic
  • non-photosynthetic
  • heterotrophic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what are synapamorphies?

A

characteristics present in an ancestor and is shared among the evolutionary descendants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what are the 2 layers of epithelial tissue found in all animals?

A
  • endoderm
  • ectoderm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

endoderm

A

digestive system and organs like liver, lungs…
develops into gastrodermis (lining of gut cavity)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

ectoderm

A

CNS and skin
develops into epidermis (outer layer od body wall)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what do the ectoderm and endoderm form?

A

A developing blastula

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what is a blastula?

A

the early stage of an animal embryo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

mesoderm

A
  • 3rd layer of tissue only found in “higher” animals
  • gives rise to muscles and organs between digestive tract and skin, supportive and contractile cells and blood cells
  • found in triploblast organisms -> most triploblasts posses organ systems (e.g. digestive system, nervous system…)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

protostomes

A

develop mouth first

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

deuterostomes

A

develop anus first

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what are HOX genes?

A
  • group of related and very conserved genes in animals
  • transcription factors that control the body plan along the head-tail axis
  • promote the transcription of certain genes
  • vary due to genetic reshuffling
  • abundant in different parts of the body e.g define if tail or no tail
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what is the holobiant concept?

A

every animal is in a complex community
- bacteria cells outnumber host 10:1
- bacterial genome is larger -> more space for adaptations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

body plans

A

group of characteristics shared by a group of phylogenetically related animals at some time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

adaptive radiation in dogs

A
  • dogs share ancestry with wolves and other canids
  • dogs are derived from grey wolves only
  • humans “selected” dogs that do well
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

canids

A

dog-like carnivores

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

not adaptive radiation in dogs example

A
  • reproductive seperation and limited effective population sizes of established breeds
  • opportunity for divergence by genetic drift
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

adaptive radiation in dogs example

A
  • breeds under selection for morphological and behavioural traits
  • selection due to humans
  • breeds that do well are favoured
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what forms the spectrum of carnial variation?

A

the combindation of adaptive and not adaptive radiation
- determines things like the bite force or breathing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

modularity

A
  • independence among groups of phenotypic traits
  • if one changes, others are affected
  • can help an organism avoid tradeoffs and likely alter the rate & direction of evolution
  • may predispose dogs for rapid jaw length evolution
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

dog skull variation

A
  • dogs have more diverse jaws and skulls than wolves do
  • jaw comprises a module seperate from the cranium -> changes in jaw can be done without affecting the cranium
  • jaw shape can change quite rapidly -> modularity -> due to very few genetic changes (which wont affect the whole skull)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

dolichocephalic

A

long-faced breeds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

brachycephalic

A

short-faced breeds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

genetic basis for dog skull variation

A
  • GWAS = at least 5 genetic regions / loci responsible for the cranioskeletal differences between dolichocephalic and brachycephalic breeds
  • BMP3 mutation fixed among extreme brachycephalic breeds (pugs)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

BMP (bone morphogenetic protein)

A

role in craniofacial development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

central dogma of molecular biology

A

replication -> DNA -> transcription -> RNA -> translation -> proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

morpholinos

A

molecules used & designed to block the activity of certain genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

what are species?

A
  • DARWIN=set of individuals closely related resembling each other
  • group of organisms with individuals capable of exchanging genes / interbreeding
  • a principle taxonomic unit
  • when at a certain point genes will no longer flow between two groups
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

what does it mean if an offspring is born highly altrical?

A

it is underdeveloped
will develop in the marsupium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

what is the marsupium?

A

a pouch that protects eggs, offspring and reproductive structures
in female marsupial mammals

51
Q

what are eutherians?

A

placental mammals

52
Q

how were mammals traditionally classified?

A

based on the number of openings in the skull

53
Q

anapsida (skull)

A

no temporal openings

54
Q

synapsida (skull)

A

one temporal opening

55
Q

diapsida (skull)

A

two temporal openings

56
Q

what did mammals evolve from?

A

synapsids

57
Q

which period did true mammals evolve from?

A

the triassic period (252-201mya)

58
Q

what are ghost linages?

A

time periods where there is no actual fossil record and other fossils or genetic data is needed

59
Q

mammary glands

A
  • derived from apocrine-like glands
  • initial function immune system related?
  • need for suckling
60
Q

suckling

A

ability to draw milk into the mouth from the nipple or teat of a mammary gland

61
Q

hyoid bones

A
  • solitary U-shaped bone in the middle of the neck
  • vertebrae throat muscles attached
  • muscles needed for the suckling movement
62
Q

why can humans hear more frequencies?

A
  • the “lost” bone wandered to the ear and aids the ability to hear more frequencies
63
Q

what are examples of the only egg laying mammals?

A
  • platypus
  • the four echidna
64
Q

distinguishing characters of egg laying mammals

A
  • no teeth
  • jaw bones and muscles different
  • have two shoulder girdle bones
  • hind leg spurs
  • use electroreception to find prey
  • low metabolic rate
65
Q

placental mammals

A
  • wait longer before they give birth to offspring
  • have a more developed placenta
  • longer gestation
  • shorter time dependent on mother
66
Q

tectonics and mammals

A

seperation of main mammal clades likely due to pangea breaking up / tectonics

67
Q

what is the main factor that determines if a species will survive a mass extinction event?

A

geographic dispersal
-> wider geographic dispersal = more chance of finding food and shelter…

68
Q

hamilton´s rule of kin selection

A

rB > C
where:
r=relatedness
B=benefit to recipient
C=cost to altruist

69
Q

what is a transitional mutation?

A
  • point mutation
  • neutral change
  • purine to purine
    example: T->Cor A->G
70
Q

how many cervical vertebrae to cetaceans have?

A

7

71
Q

which group of vertebrates have the most variation in estimates of background extinction rate?

A

amphibians

72
Q

allopatric speciation

A

species seperate due to a physical barrier like a mountain range or body of water
are now unable to breed with each other

73
Q

sympatric speciation

A

no physical barrier an members of a population are close together
species seperate due to food barrier or spontanous characteristic developments

74
Q

what is meant by a living fossil?

A

an extant species with a highly conserved and ancient body plan

75
Q

what are extant species?

A

species that exist and are not extinct

76
Q

what does speed of speciation depend on?

A
  • time
  • geography
  • lineage effects
77
Q

what is prezygotic isolation?

A
  • occurs before the formation of a zygote took place
  • mating does not need to occur
  • occurs faster
  • arises earlier among sympatric taxa than alloptric taxa
78
Q

what is postzygotic isolation?

A
  • isolation after members of two different species have mated and produced a zygote
  • offspring = hybrid
    -> hybrid often unable to mate itself so hybrid production not always considered succesful mating
79
Q

what is reinforcement in terms of isolation?

A

the enhancement of prezygotic isolation in sympatry by natural selection

80
Q

adaptive trait

A

enhances fittness (compared to some alternative trait)

81
Q

adaptation / adaptive evolution

A

changes in living organisms that allow them to successfully live in an environment

82
Q

why do living organisms change?

A

to cope with biotic/abiotic stresses and pressures

83
Q

what are radiations?

A

high rates of speciation into diverse groups

84
Q

what are adaptive radiations?

A

the evolution of ecological and phenotypic diveristy within rapidly multiplying lineages

85
Q

what are adaptive radiations the result of?

A

divergent natural selection from environments, resources, competition

86
Q

ecological speciation

A

reproductive isolation associated with different ecologies, often overcoming gene flow

87
Q

what can phenotypic differenatiation between populations or species be caused by?

A

differences in their environments and resources

88
Q

what does divergence in phenotype result from?

A

resource competition

89
Q

criteria of adaptive radiations

A
  1. common ancestry
  2. phenotype-environment correlation
  3. trait utility
  4. rapid speciation
90
Q

what is an amniote?

A
  • group of vertebrates that undergo embryonic or fetal development within an amnion.
  • include mammals, reptiles and birds
  • have a membrane surrounding the fetus
91
Q

where do amniotes lay their eggs?

A

on land instead of water

92
Q

what is an anamnoite?

A
  • a vertebrate animal that lacks an anmnion, chorion and allantois during embryonic development
  • fish and amphibians
93
Q

where to anamniotes typically lay their eggs?

A

in water

94
Q

caecilians

A
  • amphibians (“blind snakes”)
  • poor fossil record
  • legless, dermal scales, blunt head (digging), retractable sensory tentacles, internal fertilisation…
  • 160 species
  • found worldwide in tropics except for madagascar and papa-new guinea
95
Q

caudata

A
  • salamanders and newts
  • reduced skulls, well developed tails (cant fully fall off), external fertilisation, some lungless (breathe through skin)
  • long lived
  • 400+ species
  • found in the northern hemisphere
96
Q

anura

A
  • frogs and toads
  • short, no tail, long muscular hind limbs (for strength and grip), shortened vertebral column (support when jumping), mostly external fertilisation
  • 6775+ species
  • everyhwere except polar, high altitude and deserts
97
Q

why are there so many frogs?

A
  • anuran radiation after the neobatrachian radiation which accounted for 88% of the frogs
  • late crataceous extinction
98
Q

what is a key innovation?

A
  • an adaptive breakthrough or key adaptation
  • a new penotypic trait allowing further radiation and success of a taxonomic group
99
Q

examples of key innovations in frogs

A
  • new reproductive modes
    -> brook breeding: clustered clutches
  • defensive toxins
    -> anti-predator defence
  • direct development
    -> eggs not laid in water and movement towards terrestrial
100
Q

where did birds come from?

A
  • characteristics of reptiles
  • some birds used to run on hind legs
  • dinosaurs / jurassic birds
101
Q

evidence for evolution of birds

A
  • fossil record
  • comparative anatomy
  • modern evidence
102
Q

archaeopteryx

A
  • able to fly/glide
  • body-axis elongated
  • lizard-like
  • long tail with feathers in parallel rows
  • forelimb: 3 clawed digits
  • used as a wing: feathers on ulna and back of hand
  • small wing area, rounded shape
  • skull like a reptile
  • sharp teeth
  • enlarged feathers acted as “nets”
103
Q

pygostyle

A
  • in birds
  • fused final few vertebrae
  • has an evolutionary advantage
  • flight control -> allows the bird to manipulate the tail
104
Q

deinonychus antirrhopus

A
  • dromaeosaurid therpod dinosaur
  • 3.4m long
  • small body, sleek horizontal posture, enlarged raptor claws -> active and agile predator
105
Q

are reptiles cold or warm blooded?

A

cold blooded
-> can move fast but only for a short period of time

106
Q

bambiraptor feinbergi

A
  • velociraptorine dromaaeosaurid
  • no feathers on fossil but classed in feathered group
  • enlarged cerebellum -> agility and higher intelligence
  • large optic lobes, possible overlapping field of visison -> good vision?
  • hindlimb proportions good for running
107
Q

sinosuaropteryx

A
  • most primitive organism found with fossil “feathers”
  • not closely related to the achaeopteryx
  • furry “down” -> 2 branched filaments
  • arboreal -> climbed trees (to avoid predators)
108
Q

confuciusornis

A
  • toothless “beak”
  • first with no long tail and a fused vertebrae -> pygostyle
  • 6 species identified
    -> now widely accepted that birds evolved from dinosaurs
109
Q

cursorial

A

group up (evolution of birds)

110
Q

arboreal

A

trees down (evolution of birds)

111
Q

new cursorial theories

A
  • broodingb behaviour
  • wing assisted incline running
112
Q

what is the cursorial origin?

A
  • flight evolved from dinosaurs found on the ground
  • running bipeds lept into air to catch prey
  • wings then evolved for stabilising
  • evolution of feathers -> non-flight related
113
Q

non-flight selective reasons for the evolution of featehrs

A
  • display and sexual selection
  • shield from heat
  • trap insects
  • water repellent
  • shading (to enable hunting to be easier)
114
Q

problems with cursorial theory

A

biomechanically untenable
- against downward pull of gravity
- weak mechanical approach
- outcome energetically expensive
- origin of feathers not explained
- origin of brain enlargement not explained
- evolution of flight stroke in ancestors of birds not explained

115
Q

what is the arboreal origin?

A
  • feathers: aerodynamic use - arboreal, gliding animal
  • asymmetrical vanes: aerodynamic function
  • pennaceous feathers evolved first: origin was flight rather than insulation
  • evolutionary needs for feather lengthening: use wings for flight
  • feathers as airfoils
116
Q

what are pennaceous feathers?

A

feathers in the wings

117
Q

cursorial origin: brooding

A
  • wings and feathers on wings used to cover eggs or chicks
  • wings are often extended or drooped -> shelter and warmth
  • oviraptorid dinosuars may have incubated like modern birds -> similarity between dinosaur and avian incubation
  • forelimb position of nesting oviraptorid: selective advantage by increasing area of cover around the adult
  • flight used folded wing with elongated feathers a secondary adaptation
118
Q

wing assisted incline running

A
  • seen in current living birds
  • proposed as a version of cursorial origin of flight
  • aerodynamic functions from running quickly up steep slopes
119
Q

why did flight evolve?

A
  • avoid predators
  • invade arboreal habitats
  • exploit new resources
  • modified locomotory andneurosensory control
  • search for mates
  • migrate rapidly and cheaply
120
Q

requirements for flight

A
  • low weight & higher power
  • high surface/weight ratio
  • powerful propellant system -> effective way to move themselves (high temp, high metabolic rate, high performance respiratory and muscular sytsem
121
Q

adaptations for flight

A
  • thin sheets and tubes of bone
  • air sacs
  • no teeth or heavy jaws
  • food eaten quickly digested and have a high energy value
  • little accumulation of fat
  • young develop outside body (females do not carry young)
122
Q

what is insect sociality?

A
  • living in large groups (supporting / benefiting each other)
123
Q

why live in a group?

A

animal biology (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions