Midterm 2: plant structure and function (angio+gymno), fungi, ch 44 (animals), ch 24 (human evolution) Flashcards
(320 cards)
1
Q
4 main groups of land plants:
A
- bryophytes (mosses and liverworts)
- pteridophytes (ferns)
- gymnosperms (conifers)
- angiosperms (flowering plants)
2
Q
what plants first acquired vascular tissue?
A
ferns
3
Q
5 characteristics of monocots
A
- 1 cotyledon
- veins usually parallel
- vascular bundles usually complexly arranged
- fibrous root system
- floral parts usually in multiples of 3
4
Q
5 characteristics of dicots
A
- 2 cotyledons
- veins usually netlike
- vascular bundles usually arranged in a ring
- taproots
- floral parts usually in multiples of 4 or 5
5
Q
4 major events in the evolution of land plants
A
- bryophytes from algal ancestors
- vascular tissue in pteridophytes
- seeds/pollen in gymnosperms
- flowers in angiosperms
6
Q
where does most photosynth occur in a plant?
A
the leaves
7
Q
3 major tissues in leaves:
A
- epidermis
- mesophyll (Photosynth)
- veins (bulk transport)
8
Q
what is the cost of acquiring CO2?
A
several hundred w molecs lost for every 1 CO2 molec acquired
9
Q
stomata allow
A
CO2 to diffuse into the leaf
10
Q
stomata are
A
hydrochemical valves
11
Q
stomata make up what % of the leaf’s surface?
A
1-2%
12
Q
how do the guard cells surrounding the stomata open?
A
inc the [] of solutes - req ATP
13
Q
guard cells respond to (2)
A
- CO2 demand
2. w loss
14
Q
what stimulates opening?
A
light
15
Q
what stimulates closing (2)?
A
- high levels of CO2 inside the leaf
- dehydration
16
Q
other leaf functions (4)
A
- protection
- climbing
- trapping
- attracting pollinators
17
Q
xerophytes are
A
plants adapted to arid climates
18
Q
trichomes
A
hairs; break up the flow of air
19
Q
where does bulk transport occur?
A
btwn roots and leaves
20
Q
phloem
A
outer vascular tissue that transports carbs from the leaves to the rest of the plant
21
Q
xylem
A
inner vascular tissue that transports w and minerals from the roots to the leaves
22
Q
two types of ground tissue
A
- pith
2. cortex
23
Q
3 functions of ground tissue
A
- Photosynth
- storage
- support
24
Q
xylem structure (3)
A
- dead, hollow conduit
- single or multiple cells stacked to form a hollow tube
- hydrogen bonds
25
phloem structure (3)
1. living, simplified cells
2. sieve plates with large pores
3. carbs, amino acids, N, ions, hormones up and down
26
what are the 3 main nutrients taken up by roots?
N, P, K
27
mycorrhizae are
symbioses btwn roots and fungi
28
mycorrhizae (2)
- enhance nutrient uptake (P)
| - fungi receive carbs
29
what elements limits agriculture?
N
30
what do N-fixing bacteria transform N gas into?
ammonium ions
31
what are roots used for (4)?
- adhering
- prop roots
- storage
- O acquisition
32
hormone means
"to excite"
33
hormones are
chem signals produced in 1 part of the body and trigger responses in target cells and tissues
34
tropism
growth toward or away from stimuli
35
what 2 tropisms do plants display?
1. +ive phototropism
| 2. gravitropism
36
who did the tropism experiment?
Darwin and his son (1875)
37
what was the conclusion from the Darwin's experiment?
that signals are transmitted from the tip downward (Auxin hormone)
38
what is 2ndary growth?
when the vascular cambium produces cells that differentiate on both its sides (rings in a tree)
39
where are 2ndary xylem located?
inside the vascular cambium
40
where are 2ndary phloem located?
outside the vascular cambium
41
what do wide growth rings indicate?
higher growth rates
42
what do narrow growth rings indicate?
slow growing
43
wood is
primary xylem
44
2ndary xylem (2)
- strength and stability
| - transports w and nutrients from the roots to the leaves
45
what do fungi do?
decompose (cellulose and lignin)
46
how many species of fungi are known?
75,000
47
how many species of fungi worldwide?
5 mill
48
fungi are (2)
- euks
- multi
- heterotrophs
49
what are 4 ways fungi differ from plants?
1. nutritional mode
2. cell walls
3. growth
4. repro
50
who are the closest relatives to fungi?
animals
51
how do fungi acquire nutrients?
absorption
52
what do exoenzymes do?
digest food outside its body into simpler, absorbable compounds
53
hyphae
tiny filaments that make up fungi
54
mycelium
densely branched network of hyphae
55
chitin
a strong but flexible polysaccharide
56
septa
divide hyphae into cells
57
no septa in hyphae
continuous cytoplasmic mass w/ hundreds of nuclei
58
are fungi sexual or asexual?
both
59
are hyphae and spores usually haploid or diploid?
haploid
60
plasmogamy
occasionally 2 genetically different hyphae fuse
61
heterokaryon
mycelium w/ 2 genetically distinct nuclei
62
karyogamy
fusion of the haploid nuclei contributed by the 2 parents
63
when do fungi reproduce sexually?
if conditions deteriorate
64
is there a multicellular diploid stage in zygosporangia?
no
65
how many ascomycota species have been described?
over 60,000
66
ascus
a sac containing 8 spores formed during sexual repro
67
how many basidiomycota are there?
about 25,000
68
what types of fungi are in phylum basidiomycota?
mushrooms, shelf fungi, puffballs
69
basidium
club-like structure that produces sexual spores
70
mold
a rapidly growing, asexually reproducing fungus
71
yeasts
unicellular fungi that repro asexually by budding
72
lichens
mutualistic symbiosis of Photosynth microorganisns held in fungal hyphae
73
what are 2 photosynthetic partners in lichen associations?
green algae or cyanobacteria
74
where did most animal phyla arise?
Precambrian seas
75
how long ago did animals arise?
500-600mya
76
what geological site most accurately captures the Cambrian explosion?
Burgess Shale, BC
77
gastrula
a blind pouch formed during gastrulation which prod endo/ecto/mesoderms
78
are hox genes highly conserved?
yes
79
define highly conserved
moves through time relatively unchanged; high resistance to mutations
80
larval stages of animals are (4)
1. sexually immature
2. morphologically distinct
3. diff foods and habitats
4. undergo metamorphisis to attain adult morph
81
animals are/have/do (9)
1. multi, heterotrophic euks
2. ingestion
3. no cell walls
4. collagen
5. nervous and muscle tissue
6. sex
7. gastrula
8. hox genes
9. larval stages
82
what are the 9 major animal phyla?
1. chordata
2. mollusca
3. annelida
4. arthropoeda
5. Echinodermata
6. porifera
7. cnidaria
8. platyhelminthes
9. nematoda
83
chordata contains
mammals, reptiles, fish
84
mollusca contains
snails, clams
85
annelida contains
segmented worms
86
arthropoeda contains
insects/crustaceans
87
porifera contains
sponges
88
cnidaria contains
jellies
89
platyhemlinthes contains
flatworms
90
nematoda contains
roundworms
91
what is the animal clade's common ancestor?
a colonial flagellated protist similar to modern choanoflagellates
92
what's a hypothesis regarding animal evolution?
a colony of identical cells evolved into a hollow sphere; cells invaginated, creating a gut
93
how many animal phyla are there?
35
94
what is the old animal phylogeny based on?
morphology and embryology
95
what are 4 structural changes in the new tree?
1. tissue
2. symmetry
3. body cavity
4. development
96
parazoa lack
true tissue (sponges)
97
eumetazoan have
true tissue
98
what type of symmetry do animals in cnidaria have?
radial
99
cephalization is linked with bilateral symmetry. what is cephilization?
[] of sensory equipment at the anterior end
100
diploblastic means (3)
1. 2 germ layers
2. ectoderm develops into outer covering and the central nervous system
3. endoderm lines developing digestive tube
101
are Radiata (cnidaria) diploblastic?
yes
102
are bilateria triploblastic?
yes
103
triploblastic means (2)
1. mesoderm btwn ecto and endoderm
| 2. develops into muscles and many other organs
104
bilateria are further sectioned into having a body cavity or not. do platyhelminthes have a ceolem?
no
105
in terms of body cavities, nematoda are considered
pseudoceolomates
106
ceolomates have a true coelom, define true coelom
fluid-filled cavity completely lined by mesoderm
107
2 benefits to having a true coelom
1. cushions internal organs
| 2. hydrostatic skeleton
108
what 3 phyla are protostomes?
mollusks, annelids, arthropods
109
what 2 phyla are deuterosomes?
echinoderms and chordates
110
what type of cleavage to protostomes undergo?
spiral, determinate
111
what type of cleavage do deuterostomes undergo?
radial, indeterminate
112
what does the blastopore in protostomes develop into?
mouth
113
what does the blastopore in deuterostomes develop into?
anus
114
what does it mean when you see a polytomy (flat line) on a tree?
don't have the molec resolution to know what came 1st
115
the old and new tree are alike in 3 branchings: (but different on the rest)
1. no tissues vs tissue
2. radial vs bilateral
3. protostomes vs deuterosomes
116
animals with pseudocoeloms or no coeloms at all are no longer considered more primitive they are thought to have
lost their coeloms
117
ecdysozoa (2)
- molt old exoskeleton and secrete a new, larger one (ecdysis)
- nematoda and arthropoda
118
how many extant species of animals are currently identified?
more than 1mill
119
what % of animals are vertebrates?
5%, u biased fucka
120
porifera (3)
1. sessile
2. lack nervous tissues
3. suspension feeders
121
what lies inside the internal chambers of perforations in porifera?
flagellated choanocytes that trap food with their collars
122
how do sponges distribute nutrients across their cells?
amoebocytes
123
what forms spicules?
amoebocytes
124
what are hermaphrodites and what phylum is one?
prods both sperm + eggs; porifera
125
how many living species of cnidaria are there?
10,000
| - mostly marine
126
4 examples of cnidaria
1. hydras
2. jellies
3. ovemones
4. corals
127
2 variations of cnidaria
1. sessile polyp
| 2. floating medusa
128
medusas (eg. jellies) are mouth-down versions of what?
polyps
129
are cnidarians herbivores or carnivores?
carnivores
130
what are nematocysts?
organelles in cnidaria's stinging tentacles that evert a poisonous, entangling thread
131
are hydras found in fresh or salt w?
fresh
132
how do hydras do sex?
- repro asexually via budding
| - when env conditions deteriorate, they do sex (lesistant zygotes)
133
corals (4)
1. are polyps
2. are colonial
3. secrete a hard exoskeleton of calcium carbonate
4. build on the remains of earlier generations
134
sea anemonies are a mutualistic symbioses with
Photosynth dinoflagellates
135
lopotrochozoa
animals that do not perform ecdysis
136
why do platy's have flat bodies?
diffusion
137
what are 2 parasitic platy's?
flukes and tapeworms
138
trematode fluke Schistosoma infects 200 mill ppl and causes serious illness (3)
1. anemia
2. dysentery
3. swimmers itch
139
what anchors a tapeworm in a digestive tract?
scolex (suckers and hooks)
140
proglottids
sacs of sex organs
141
how would you get a tapeworm outside of Canada?
undercooked meat
142
how would you get a tapeworm inside of Canada?
undercooked game
143
tapeworm/human lifecycle (5)
1. proglottids leave in hosts feces
2. eggs ingested by intermediary hosts, usually pigs or cattle
3. larvae encyst in muscles
4. humans eat undercooked meat contaminated with cycts
5. mature in human
144
mollusca are (3)
- marine
- soft-bodied
- hard shell of CaCarbonate (some reduced, like octopi, slugs, squids)
145
3 features of mollusca's body plan
1. muscular foot
2. visceral mass
3. a mantle
146
what does the mantle do?
drapes over the visceral mass and secretes shell
147
how do mollusca eat?
scrape food using radula
148
molluska sex
- most are separate sexes,
| - snails are hermaphrodites
149
what type of larva do marine mollusks have?
tropophore (same as annelids)
150
4 types of molluska
1. chitons
2. snails and slugs
3. bivalves
4. squid + octopuses
151
chitons are (2)
1. marine
| 2. oval
152
how many dorsal plates are chitons shells divided into?
8
153
most snails and slugs are (2)
- marine
| - protected by single, spiralled shells (if no shell, chem defenses)
154
during embryonic development, snails undergo torsion
visceral mass is rotated up to 180 deg
155
some species of snails/slugs are predators. how are their radula's modified?
to bore holes in the shells of other orgs
156
what functions as a lung in terrestrial snails?
lining of the mantle cavity
157
4 examples of bivalves
1. clams
2. oysters
3. mussels
4. scallops
158
what are bivalve abductor muscles used for?
closing the shell to tightly protect the animal
159
bivalves are suspension feeders. track the path of w
enters via incurrent siphon, passes over gills, exits via excurrent siphon; traps fine particles in gill mucus and the cilia convey them to the mouth
160
squid/octopi have a well-developed nervous system (4)
1. complex brain
2. well-developed sense organs
3. eyes similar to vertebrate eyes
4. capable of learning
161
where do you find annelida's?
freshw, damp soil, marine
162
3 types of annelida
segmented worms: polychaetes, leeches, earthworms
163
is the coelom of an annelida partitioned?
yes, by septa
164
annelidan digestive system consists of (4)
esophagus, crop, gizzard, intestine
165
do annelids have an open or closed circulatory system?
closed
166
metanephridia
excretory tubes that act like kidneys, found in each segment of an annelidan
167
annelids have cerebral ganglia. are they cephalized?
yes
168
earthworm sex
crossfertilizing hermaphrodites
169
polychaete locomotion
each segment has paddlelike parapodia
170
feather-duster polychaetes eating
trap plankton on feathery bristles
171
where do leeches live?
fresh w, some terrestrial
172
what do leeches secrete?
hirudin, an anticoagulant
173
where are nematoda found (4)?
- aquatic habitats
- wet soil
- plant tissue
- body fluids of animals
174
what do nematoda play a major role in?
decomposition
175
nematoda repro
sexual reproduction (up to 100,000 eggs per day)
176
do nematoda have a complete digestive tract?
yes
177
what do nematoda cause?
Trichinella Spiralis (undercooked meat)
178
how many arthropod species are there?
over 1 million (2/3 of species)
179
the success of arthropods is due to (3)
- body segmentation
- hard exoskeleton
- jointed appendages
180
what are arthropod exoskeletons made of?
protein and chitin
181
what's one disadvantage of doing ecdysis?
left temporarily vulnerable when molting
182
what are 3 functions of an exoskeleton?
1. protection
2. locomotion
3. prevents w loss on land
183
what are the 4 main evolutionary lineages of arthropods?
- Cheliceriformes
- Myriapoda
- Hexapoda
- Trilobita
184
what are 3 examples of a cheliceriform?
spiders, horseshoe crabs, scorpions
185
what are 2 examples of a myriapoda?
cent + milipedes
186
hexapoda
insects
187
2 examples of crustacea
- lobsters
| - barnacles
188
trilobites died in what extinction?
Permian, 250 mya
189
living fossil
has not changed much from its ancestors (eg horseshoe crab)
190
how does gas exchange occur in spiders?
book lung with extensive SA
191
how many pairs of walking legs per segment do millipedes have?
2
192
how many pairs of walking legs per segment do centipedes have?
1
193
millipedes are (2)
- herbivores
| - among the earliest land animals
194
centipedes are (2)
- carnivores
| - have poison claws
195
insects inhabit (3)
terrestrial habitats, fresh w, air
196
how long do fossils date back for insects?
400mya
197
flight is key to the success of insects; it allows insects to (3)
- escape
- find food and mates
- disperse
198
metabolic wastes in insects are removed by
malpighian tubules (kidney)
199
what does the tracheal system in insects do?
carries O2 from spiracles directly to cells
200
do insects have brains?
yes; 2 ventral nerve chords fusing into a cerebral ganglion
201
incomplete metamorphisis
young resemble adults
202
complete metamorphisis
larval stages change morphology completely during pupal stage
203
what are 3 things insects use to mate sexually at the right time?
1. colouration
2. sound
3. odour
204
spermatophores are
sperm packets deposited by the male
205
spermatophores can contain additional nutrients such as
nuptial gift (sometimes the male)
206
where do female insects lay their eggs?
on/in a larval food source
207
affect other terrestrial orgs in 3 ways
1. pollination
2. vectors for diseases (malaria, African sleeping sickness, west nile virus, plague)
3. pesticides
208
crustaceans are mostly marine. what is one example of a terrestrial crustacean?
wood bug
209
are barnacles mollusks or crustaceans?
crustaceans
210
what are 5 types of crustaceans?
1. lobsters
2. crabs
3. crayfish
4. shrimp
5. barnacles
211
where do echino's live?
marine env's only
212
what type of symmetry do echinoderms have?
pentaradial (metamorphosis from bilateral larva)
213
what are 3 functions of tube feet?
1. locomotion
2. feeding
3. gas exchange
214
what is the w vascular system?
a network of hydraulic canals branching into extensions called tube feet
215
3 classes of echino's that are of interest for us:
1. sea stars
2. sea urchins/sand dollars
3. sea cuces
216
3 steps to sea stars eating bivalves
1. pull apart shells with tube feet
2. evert its stomach btwn the shells
3. enzymes break down soft bivalve body
217
all chordata at some point in their life-time share (4)
1. notochord
2. dorsal hollow nerve chord
3. pharyngeal slits
4. muscular, post-anal tail
218
notochords are
cartilage-like flexible rod
219
notochords are present in
chordate embryos
220
notochords provide
skeletal support
221
the dorsal hollow nerve cord develops from the
ectoderm
222
the dorsal hollow nerve cord becomes
the central nervous system (brain + spinal cord)
223
pharyngeal gill slits are often modified for
suspension feeding or gas exchange
224
pharyngeal slits function to
connect the pharynx to outside + allow w to exit w/out entering the digestive tract
225
muscular tail ending location
posterior to anus
226
what does the muscular tail become in aquatic species?
a propulsive force
227
what are 2 representatives of urochordate?
1. tunicates
| 2. sea squirts
228
cephalochordata
lancelets
229
vertebrata are characterized by (4)
1. cranium
2. pronounced sephalization
3. vertebral column
4. closed circulatory system
230
neural crest
a group of embryonic cells that contribute to the bones of the cranium
231
what are 2 examples of agnathans (jawless vertebrates)
hagfish and lamprey
232
how many species of hagfish are there?
30
233
what are hagfishes cranium and notochord made of?
cartilage
234
how many species of lamprey are there?
35
235
lampreys are
ectoparasites
236
when did jawed animals replace agnathans
360 mya
237
2 major breakthroughs of fish:
1. jaws enable them to grip food firmly
| 2. paired fins enabled them to manouver accurately
238
chonrichthyes types (3)
sharks, rays, ratfish
239
what are chondrichthyes endoskeletons made of?
cartilage
240
how do chondrichthyes attain buoyancy?
oils in liver
241
what happens if a shark stops moving?
it dies
242
oviparous
encase eggs in a protective case and lay them externalls
243
ovaviviparous
retain fertilized eggs in oviduct; nourished by egg yolk; live birth
244
vivaparous
live births; nourished in uterus via placenta
245
what are the 3 classes boney fish can be split into?
ray-finned fish, lobe-finned fish, lungfish
246
what is the function of an operculum?
- protective flap
| - draws w over gills
247
what type of boney fish may have given rise to tetrapods?
lobe-finned fish
248
what does it mean to aestirate?
warm weather hibernation
249
when did tetrapods move to land?
about 360mya
250
what 2 animal types are in class amphibia?
salamanders and frogs
251
define amphibian
2 lives - metamorphosis from aquatic tadpole to terrestrial adult
252
what are 3 ways amphibians retain close ties with w?
1. moist skin carries out gas exchange
2. eggs lack a shell and dehydrate in air
3. most have external fertilization
253
who are in the amniotes clade?
1. mammals
2. birds
3. reptiles
254
3 adaptations amniotes made for terrestrial living
1. amniotic egg
2. wproof skin
3. ribs to ventilate lungs
255
what enables life cycles of amniotes to be entirely on land?
amniotic eggs (shell retains w)
256
what are 3 sections of "reptiles"?
lepidosaurs, archosaurs, turtles
257
what 2 animal types make up the lepidosaurs?
1. lizards
| 2. snakes
258
what 3 animal types make up the archosaurs?
1. crocodiles
2. dinosaurs
3. birds
259
ectotherm
absorb env heat
260
what is one advantage of being an ectotherm?
10% of calories req'd by mammal of equivalent size
261
endothermic
keep body w through metabolism
262
are birds endo or ectothermic?
endothermic
263
how are the sexes of turtles determined?
temp
264
are crocodiles hetero or homodont?
homo
265
what are 3 ways bird anatomy is modified to red. weight?
1. 1 ovary
2. toothless (gizzard)
3. bones are honeycombed
266
how many chambers does a birds heart have?
4
267
what is the function of downy feathers?
trap air; insulation
268
contour feather function
aerodynamic shape
269
filoplume feather function (3)
- maintains the position of contour feathers during flight
- display
- tells how the contour feathers are angled
270
what did Archeopteryx have that made it resemble the modern bird (3)
1. clawed forelimbs
2. feathers
3. tail w/ vertebrae
+ teeth
271
when did adaptive radiation for mammals occur and why?
65 mya when the dino's died
272
what is the defining characteristic of class mammalia?
mammary glands + hair
273
name 4 types of teeth in mammals heterodont mouths
1. incisors
2. carnivores
3. premolars
4. molars
274
3 modern groupings of mammals
1. monotremes
2. marsupials
3. eutherians
275
monotremes
egg-laying mammals
276
marsupials
pouched mammals
277
eutherians
well-developed placental stages
278
2 living examples of monotremes
1. platypuses
| 2. echidna's
279
3 types of marsupials in Canada
1. possums
2. kangaroos
3. koalas
280
what are 7 adaptations primate made for arboreal life?
1. hands/feet for grasping
2. large brains
3. short jaws
4. flat nails, not claws
5. parental care & complex social behaviour
6. depth perception
7. excellent hand-eye coordination
281
opposable thumbs found only in
anthropoid primates
282
who are in the prosimians?
lemurs, lorises, tarsiers
283
who are in the anthropoids?
monkeys, apes, humans
284
old world monkeys are both ground-dwelling and arboreal. what are new world monkeys?
just arboreal
285
5 types of apes
1. gibbons
2. orangs
3. gorillas
4. chimps
5. bonobos
286
how long ago did apes diverge from old world monkeys?
25-30mya
287
gorillas and chimps are highly
social
288
only gibbons are orangs are
primarily arboreal
289
how many yrs of evo did huans and apes share?
3.5 bill yrs (except for the last 6 mill yrs)
290
how many species of primates?
approx. 400
291
3 physical traits unique to primates
1. opposable thumbs
2. eyes on the front of face
3. nails instead of claws
292
what % diff in DNA sequence is there btwn humans and chimps?
1% (1 deg diff in denaturation temps)
293
how long ago were we tree dwellers?
30-35mya
294
20mya the climate became drier and the savanna habitat inc. what did this mean for the primates?
less arboreal life -> divergence
295
diverged from a common ancestor
approx. 5-7mya
296
4 big diffs btwn us and chimps:
1. brain size triples over the past 6 mill yrs
2. bipedal posture: hominoid ancestors walked on all 4 limbs
3. jaw shape: ancestors had longer jaws than modern humans (+ changes in dentition)
4. reduced size diff btwn sexes (suggests monogamy became more common)
297
where did hominids originate?
eastern and southern africa
298
what came first, bigger brain or bipedalism?
bipedalism
299
famous Australopithecus fossil
lucy; found in ethiopia
300
3 Australopithecus and us similarities
1. bipedal
2. human like hands and teeth
3. chimp-sized brain
301
what did homo habilis have (2)?
1. stone tools
| 2. larger brains
302
who was the first homo to migrate out of Africa?
homo erectus
303
where did homo erectus go once they left Africa?
Europe and asia
304
when was fire use dated to?
1mya
305
where did Neanderthals live?
Europe/middle east
306
2 diffs btwn humans and neanderthals
1. larger brains
| 2. heavily built
307
did Neanderthals contnribute to the human gene pool?
yes
308
what are the 2 hypotheses for the origin of modern humans?
1. multiregional hypothesis
| 2. out of Africa hypothesis
309
multiregional hypothesis
modern humans evolved from local pops of homo erectus (genetic similarity a product of interbreeding)
310
out of africa
homo sapiens evolved from a 2nd migration out of Africa which replaced all regional pops of homo's
311
which hypothesis does the genetic data support?
out of africa
312
mitochondrial eve
mitochondrial DNA suggests a time of genetic divergence of 1 or 200,000yrs ago
313
why is mDNA good for analysis?
no crossing over
314
originally, Neanderthals were thought to be replaced, but now we think we
interbred (for Asians/Europeans)
315
y chromosomes are important for genetic data because they are passed from male to male w/out
crossing over of the x-chromosomes
316
researchers were able to infer divergence from common African ancestor
approx. 200,000yrs ago
317
what % of genetic variation in humans occurs within a pop?
85%
318
what % of genetic variation occurs btwn pops w/in races?
8%
319
what % of genetic variation occurs btwn races?
7%
320
where are the most diverse pops found?
Africa
