BIOL 111
Announcements
CORRECTION:
Vertebrate hearts: amphibians +
• Flip-flop atria and ventricle(s)
• Final lab exam, Monday November 23, 6:307:30pm
lungs
pulmonary
artery
• Clicker participation: 25 lectures + 2 (maybe
3) extra opportunities:
80% = 20 lectures (4 pts)
70% = 17 lectures (3 pts)
60% = 15 lectures (2 pts)
50% = 12 lectures (1 pt)
body
Need 80% class
participation in course
evaluation to receive 3rd
clicker opportunity.
SA node
aorta
RV
vena cava
body
LV
RA
pulmonary vein
LA
lungs
1
2
Mammals II
BIOL 111 – Organismal Biology
lecture outline
1. Primates
•
•
•
Lecture 23
Mammal II:
Characteristics
Diversity
Hominid evolution
2. Mammalian Nervous System
Primates, Hominid evolution,
Mammalian nervous system
•
•
Peripheral NS
Central NS
19 November 2009
3
Which statement is not TRUE
regarding mammal evolution?
22%
19%
15% 15%
• Arboreal, insectivorous
eutherian ancestor
• Grasping limbs with opposable
thumb*
• Forward-facing eyes
lemur
e.
ar
..
su
pi
al
s
&
e.
Th
..
e
fir
st
eu
M
on
th
...
ot
re
m
es
(p
r. .
.
M
w
am
m
al
s
er
e.
..
– Wider field of view
– Depth perception
ds
4.
5.
Primates
29%
m
3.
Sy
na
ps
i
2.
Synapsids were the dominant
tetrapod group in the Permian.
True mammals evolved from
therapsids about 220 mya (Triassic).
Marsupials & eutherians co-existed
with dinosaurs.
The first eutherians were oviparous.
Monotremes (prototherians) are the
extant mammal group that diverged
from reptiles first.
Tr
ue
1.
4
5
• Big cerebrum
• Highly social
– Reduced brood size
and extended parental care
tarsier
chimpanzee
6
1
Prosimians
Primates
• 235 species
• Two groups
• Mostly arboreal &
nocturnal
• Once found on all
continents, but now
just Africa & SE Asia.
• Lemurs on
Madagascar have
greatly radiated.
– Prosimians
• lemurs
• lorises
– Anthropoids
• tarsiers
• monkeys
• apes
crowned lemur
– humans
Cenozoic
7
Anthropoids
ring-tailed lemur
8
slender loris
Anthropoids
• Tarsiers
• Tarsiers
– Among smallest
of primates
– Very good
jumpers
– Can rotate head
180o
– Small,
arboreal,
nocturnal,
insectivores
– SE Asia
– Many
endangered
9
Anthropoids
10
New World
Monkeys
• Monkeys split
when SA & Africa
still close
• South & Central
America
• all arboreal
• most have long
prehensile tails
• relatively flat
faces
• live in groups
pygmy marmoset
spider monkey
Cenozoic
11
howler monkeys
12
2
Old World
Monkeys
Apes
mandrill
(non-apes)
• Arboreal and
grounddwelling
• No prehensile
tail
• Mandrils,
baboons,
rhesus
monkeys,
macaques
Japanese
macaque
Cenozoic
proboscis monkey
13
Asia
14
Who is our closest living relative?
lesser apes
1.
2.
3.
4.
5.
= great apes =
family Hominidae
orangutan
67%
15%
Africa
12%
4%
ee
th
er
O
C
hi
m
pa
nz
or
il l
a
O
M
on
ke
y
2%
G
gibbon
Monkey
Gorilla
Orangutan
Chimpanzee
Other
ra
ng
ut
an
Apes
• split from Old
World Monkeys
~35 mya.
• Africa & Asia
(non-human
apes)
• no tail
• bigger brain
human
gorilla
chimpanzee
15
Primate research at McGill
Chimpanzees
• lineage split ~ 6
mya
• 99% similarities in
coding DNA
• highly intelligent:
– tool use (Goodall)
– learn symbols &
numbers
– plan for future
– laughter
16
Prof Colin Chapman
– Depts: Anthropology, MSE, Biology
– Primate ecology & conservation
– Works in Kibale National Park, Uganda
Courses:
– ANTH 311 (Primate behavior & ecology)
– ANTH 411 (Primate studies & conservation, in Africa)
bonobos
Website:
http://www.arts.mcgill.ca/anthro/chapman_files/CWeb/index.
html
17
18
3
Advantages of bipedalism?
Hominids
(Hominins)
• ~20 extinct species
discovered
• Not a ladder to modern
humans, rather a branched
tree of extinctions
• Different groups co-existed
Sahelanthropus tchadensis
~6.5 mya, Chad
• Common ancestor to
chimps & humans or oldest
hominid?
• Reduced canines
• More bipedal locomotion
• Increased brain size (later)
• Less energetically costly
• Frees up forelimbs for
other tasks
• Elevates head for better
view of predators, prey
19
20
Hominid Phylogeny
Australopithecus
• “Lucy” – discovered in
1974 by Johanson &
Leakey
Laetoli
footprints,
3.5 mya,
Tanzania
Lucy
21
– Australopithecus afarensis
– 3.2 mya from Ethiopia
– Most complete hominid fossil
at the time
– 1m height, small brain
(chimp-sized), bipedal
• Evidence that bipedalism
evolved before large brain
size
22
Early Homo species still had relatively small
brains but began using tools & capable of
walking longer distances.
Hominid Phylogeny
• Homo habilis “handy man”
– 2.5-1.5 mya
– first tool use 2 mya
– shorter jaw, bigger brain
• Homo ergaster “working man”
23
– ancestor to modern humans
– 2-1.5 mya
– longer legs, shorter fingers suggesting
walking not climbing, smaller teeth
– brain 2/3rd size of modern humans
• reduced sexual
dimorphism
24
4
Hominid Phylogeny
Hominids left Africa approximately 1.6 mya.
• Homo erectus “upright man”
– 1.6 mya – 200,000 yrs ago
– first hominid to leave Africa
(Eurasia, Indonesia)
– fire & tool use
– small brains,
thick skulls,
same body size as
modern humans
25
26
Brains reached modern size about 160,000
years ago.
Hominid Phylogeny
• Homo neanderthalensis
“Neanderthals”
-- discovered in Neander Valley,
Germany, 1856
-- 200,000-30,000 ya
-- Europe & Asia only
-- short, stalky but powerful build
-- larger brain than H. sapiens?
-- co-existed with H. sapiens
(Cro-Magnons)
-- gene flow between groups?
http://www.msnbc.msn.com/id/33721697/ns/technology_and_science-science/
27
Modern humans evolved from H. ergaster
~200,000 yrs ago.
28
Have Homo sapiens been alone for
30,000 years?
77%
• Homo sapiens “wise man”
23%
Altamira paintings, Spain
Y
es
• cave paintings, carvings, antler
spears, tools for woven clothing
29
N
o
evolved in Africa (Ethiopia)
~200,000 yrs ago
arrived in North America ~20,000
more slender, lack heavy browridges of other hominids
– Cro-Magnon = “European early
modern humans” ~30,000 ya
1. Yes
2. No
–
–
–
–
30
5
Hominid Phylogeny
Another hominid species was discovered
in Indonesia in 2004.
• Homo floresiensis
– Flores island, Indonesia
– existed to ~12,000 ya
– Much smaller than H.
sapiens
Wiped out by a volcanic eruption
31
32
33
6
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