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Bio 1M03 > Week 6 > Flashcards

Week 6 Flashcards

1
Q

Def: Adaptive Radiations

A

Instances of rapid diversification of a lineage accompanied by ecological diversification

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2
Q

What triggers adaptive radiations

A

biological innovation or ecological opportunity

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3
Q

Biological Innovation

A

The application of better solutions that meet new requirements, in-articulated needs, or existing scientific needs

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4
Q

Cichild fish adaptive radiations

A

have functionally decoupled set of jaws- oral and pharyngeal, frees up jaws to independently collect and process food - allows exploitation of new niches

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5
Q

Biological innovation as a trigger

A

the evolution of many other key innovations allow ancestors to rapidly diversify, live in new areas, exploit new food sources, and move in new ways

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6
Q

Background rate of extinction

A

refers to the level of extinction during periods when mass extinctions are no occuring

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7
Q

Mass extinctions

A

periods with extreme levels of biodiversity loss
-cause extinction randomly with respect to individuals fitness

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8
Q

When do background extinctions typically occur

A

when normal environmental change, emerging diseases or competition reduces certain populations to zero

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9
Q

What do mass extinctions occur from?

A

extraordinary, sudden and temporary changes in the environment

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10
Q

Big Five mass extinctions

A

Ordovician: 50% of animal families - 500 mill years
Devonian: 30% of animal families - 345 mill years
Permian: 50% of animal families including over 95% of marine species - 250 mill years
Triassic: 35% of animal families including many reptiles and marine - 180 mill years
Cretaceous: reptiles (dinos) - 65 mill years
The sixth extinction has begun: large mammals and birds

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11
Q

What killed the dinosaurs

A

the impact hypothesis proposes that a meteorite struck earth 65 mya and caused extinction of an estimated 60-80% of multicellular species alive

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12
Q

Evidence for the impact hypothesis

A

iridium in the gulf of Mexico region, shocked quartz, microtekities and crater

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13
Q

Differential survival

A

Some evolutionary lineages are better able to survive mass extinction events than others

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14
Q

What occurred after the dinosaurs went extinct

A

ecological opportunity was presented to mammals in the tertiary period starting the age of the mammals

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15
Q

6th mass extinction

A
  • global diversity has undergone a progressive decline over the last 30,000 years
    -current rate of extinction in 100-1000 times background extinction rate
    -most human colonization is associated with environmental degradation
    -most extinctions are undocumented
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16
Q

ancient extinction

A

the extinction of large body marsupials that occurred when humans arrived in Australia

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17
Q

Historical extinction

A

Sailors killed flightless dodo birds who originally evolved with no predictors by clubbing them with sticks

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18
Q

Island fauna extinction

A

brown tree snack introduced and all flightless bird fauna

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19
Q

Extinction of once abundant fauna

A

in Hamilton there were several pigeons that would block the sun, eaten by people

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20
Q

Cichlid fish Lake Victoria

A

Nile perch were introduced from lake albert into lake Victoria for food source - eat other fish and themselves
-caused large mass extinction of contemporary vertebrates in lake Victoria including cichlids
- they ate algae and now algae bloom
-Consequences: more plant material settles on the bottom of the lake before decomposing, decreases oxygen in water
-required to be dried = deforestation

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21
Q

Life’s timeline

A

Precambrian supereon:
-hadean eon
-archaean Eon
-proterozoic eon
Post Cambrian explostion:
-phanerozoic eon: includes paleozoic era, mesozoic era (age of reptiles) and cenozoic era (age of mammals)

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22
Q

What is an animal

A

eukaryotic and multicellular
different tissue types
gut with specialized cells
motile at some point in their lives
heterotrophic (ingest other organisms)
blastula stage during development
usually sexually reproduce

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23
Q

What caused the cambrian explosion

A

Environmental change: increased oxygen concentration, thickness of ozone layer, flooding of continental shelves, increased calcium in oceans
Ecosystem engineering: animals changed their environment, opening up novel ecological niches
Developmental/ morphological innovations: possible role of developmental genes

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24
Q

What is the role of Hox genes

A

encodes protiens that bind to DNA to influence expression of other genes

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25
What do Hox genes influence and where are they located
Occur in groups along one chromosome or a set of chromosomes generally in the same order different hox genes are expressed embryonically in specific regions and trigger development of specific body parts responsible for defining what each section of the body is and where other genes orchestrate what structures form in the part of the body
26
Evolutionary Development (Evo-devo)
Transcription factors can acts as switches whereas others set up gradients that trigger biological cascades
27
How does morphological diversification occur in animals
changes in hox gene number, broad changes in hox gene expression, subtle changes withing hox domains, changes in regulation of function of downstream genes
28
What is increased complexity often attributed to
changes in gene expression as apposed to number of genes -changes can occur in time or space
29
What system in humans do hox genes play a role in
CNS, axial skeleton, gastrointestinal and urogenital tracts, external genitalia, limbs and digits
30
Mesozoic Era
Age of reptiles mammals and angiosperms first appeared
31
Cenozoic Era
Age of mammals most mammals diversified in this era First primates, apes, and homo sapiens
32
First true mammals
the cenozois era saw spectacular radiation of mammals following extinction of the dinos coupled in time and probably linked to the diversification of angiosperm
33
What is an angiosperm
a type of vascular plant that have flowers most have endosperm within seeds most produce fruit that contain the seeds most diverse group of land plants
34
Plants with vs without seed
seeds are an innovation that evolved in the ancestor of gymnosperm and angiosperm plants they contain more food resources
35
The diversification of angiosperms
by the late cretaceous angiosperms dominated habitat formerly occupied by ferns and cycads -replaced conifers as dominant trees
36
Relationship between angiosperms and animals
angiosperms evolved to depend on animals for pollination, defense and dispersal -rewarded animals with nectar fruit and shelter
37
Adaptions of primates that allow them to compete for resources
binocular vision, grasping hands and feet, nails, changes in dentition that facilitate foraging, facilitate locomotion and predate arboreal insects
38
What is a primate
-adaptations for climbing and other forms of locomotion -opposable thumbs -prehensile tails -hand-limb dominated posture -relatively short snouts -increased reliance on stereoscopic vision -nails -relatively large brains
39
Prosiminans
small brains, large olfactory lobes, bicornuate uterus, reflective layer in eyes, nocturnal
40
Tarsiers
Enormous eyes, excellent hearing, distinctive auditory cortex, long feet and fingers
41
New world monkeys
prehensile tails, lack tricolor vision, monogamous pair bonds, thumbs are not opposable, twining common in come species
42
Catarrhines
no prehensile tails, sexual dimorphisms, diurnal, grasping hands and feet
43
Homo sapiens
reduced sexual dimorphism, spoken language, increased brain size, bipedalism
44
Anthropoids
NWM, OWM and apes
45
Hominoids
Apes including humand
46
Hominis
human lineage after divergence from chimps and bonobos
47
Hunting
the practice of pursuing living things for food, trade and pest control
48
Theories of bipedalism
-cooler: less solar radiation more wind -arms more free to carry objects and forage -response to increase dependency of offspring
49
When did adaptions to suspensory locomotion occur
miocene (23-5 mya)
50
Adaptions for suspensory motion
short trunk and legs, stiff spine, long arms and fingers, hook-like fingers, opposable thumbs, shoulders more mobile, strengthening of pelvic floor
51
Chimp-human split
MRCA of chimps and humans was about 5-7mya 3 fossils - ardipithecus ramidus, orrorin tugenensis, sahelanthropus tchadensis mixture of ancestor features and derived features
52
Ancestral features of hominins
small molars, canines larger, larger brow ridge, small braincase
53
Derived features of hominins
forward location of foramen magnum, small canine teeth, changes in femur, pelvis, knee and ankle, flattening of the face
54
Australopithecus
example of a hominin 2-4 mya -small bipeds with small teeth
55
Paranthropus
example of a hominin 2-4 mya -small bipeds with big teeth - probably ate plants
56
Kenyanthropus
example of a hominin 2-4 mya -small teeth and flat face
57
Laetoli footprints
3.5 my old -illustrates that Australopithecus was bipedal
58
How are humans different from other apes
-fully bipedal -long juvenile period -dentition -large brain -spoken language -symbolic culture
59
Differences in bone structure between humans and chimps
Changed location of foramen magnum change in spine shape femur angle foot arch flattened and flared pelvis
60
When were Neanderthals around
fossil evidence presence in western Eurasia from 127,000-30,000 years ago
61
Neanderthals morphology
faces that bulge in the middle, large browridge, rounded back of skull, large cranial capacity, robust and heavily muscled bodies (may be due to cooler climate)
62
Where did Neanderthals live
Europe, western Asia and southern Siberia
63
Genetic comparison to Neanderthals
generated whole genome from 5 human populations and compared to Neanderthal genome to determine gene flow between modern humans and Neanderthals -quantified against Africa, Europe, Asia, and New Guniea -found that all non-African modern humans shared 1-4% of their genome with Neanderthals -Modern humans from africa shared none -gene flow occurred after divergence from africa
64
Are denisovans more closely related to Neanderthals or modern humans
Neanderthals
65
Is there gene flow between Denisovans and AMH
in populations from melanesia

Bio 1M03 (12 decks)

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