Exam 2 Flashcards
primates
the order of mammals that has a complex of characteristics related to an initial adaption to life in the trees
parallel evolution and example
when the same trait has arisen separately in two closely related species and is not due to arisen once in a common ancestor
ex. finches in different parts of the world have evolved similar structures independently
convergent evolution and example
independent evolution of similar adaptations in rather distinct evolutionary lines
Ex) wings in bats, insects and birds
Ex) Seen in Australia and New Zealand with placentals and marsupials
homologous vs. analogous traits
Homologous – physical traits in two species that have similar structures but may or may not show a similar function
Ex. Arms and legs both have one upper bone and two lower bones
Analogous – physical traits with similar functions in two species but a different structure
Ex. Bird and insect wings have similar function (flight) but different structures
primitive traits and example
traits that have not changed from an ancestral state
Ex. Five digits in hand and foot has not changed
derived traits and example
traits that have changed from an ancestral state
Ex. Horses have single digits while ancestors had 3 or 5
Even toes: Artiodactyls
Odd toes: Perissodactyls
phenetic and example
overall physical similarities among organisms
Ex. Overall genetic distance
cladistics and example
primitive vs. derived traits, group animals together since they have shared derived traits, evolutionary relationships between organisms (derived vs. primitive traits) are used to form biological classifications
Ex. Count shared-derived traits
humans are of the ______ (animals with a spinal cord)
phylum chordata
animals with backbones, all have bilateral symmetry
sub-phylum vertebrata
all phylum chordata possess _____ at some point (a flexible internal rod that runs along the back of an animal)
notochord
when did mammals arise?
~200 mya
what sets mammals apart from other vertebrates/
they usually give birth to live offspring rather than eggs
3 types of mammals
Marsupials (kangaroos, give birth to premature offspring and keep in pouch)
Monotremes (platypus, lay eggs)
Placental (humans, limits # of offspring)
K-selection and example
produce few offspring and invest a lot into maximizing each offspring’s chances
Ex. Primates
R-selection
produces huge number of offspring and provide little care
Ex. Fish, frogs, insects
childcare for chimps vs. humans
chimps:
- take a long time to produce offspring
humans:
- don’t wait until child iis mature to have another
homiotherms
Mammals are this;
Capable of maintaining a constant body temp under most conditions
3 ways mammals maintain homeostatis
furr insulation
vasodilation (increases heat loss, increases blood flow)
vasoconstriction (reduces heat loss, reduces blood flow)
4 types of teeth
incisors - flat front teeth used for cutting
canines - located in front, used for puncturing and defense
premolars - back teeth, crunching and grinding food
molars- furthest back, crunching and grinding food
dental formula and what do humans have
incisors: canines: premolars: molars
Humans: 2:1:2:3
allows for wide range of diet
mandible vs maxillae
mandible - lower jaw
maxillae - upper jaw
medulla oblongata
part of the hindbrain with pons and cerebellum
helps blood flow
regulates heartbeat and breathing
accounts for opiates causing trouble with breathing
pons
part of hindbrain with medulla and cerebellum
aka reticular formation
relay station carries signals from various parts coordinates body movement
involved in sleep and arousal
midbrain helps us with
vision
forebrain
chemical sensing/smell
involves thalamus (all sensory output goes through here) and hypothalamus (makes hormones)
primates vs. mammals vs. reptiles brain
p - large brains, esp. in visual aspect
m - large forebrain responsible for sensory info
r - large mid and hind brain, rely on vision and hearing
grasping hands
five digits on each hand
primitive trait for mammals
prehensile
capable of grasping with toes/feet
humans have lost this due to bipedalism
terrestrial vs. arboreal
t - living on the ground
a - living in trees (need grasping!)
primates are arboreal but several have switched to terrestrial
generalized vs. specific structures and examples
Gen – biological structures adapted to a wide range of conditions and used in very general ways
Ex. Gen limb structure is very flexible
Spec – narrowed down possible rate of uses
Ex. Horses single digit hooves are very specialized for running quickly
binocular stereoscopic vision
overlapping fields of vision, allows for depth reception
necessary adaption for life in the trees and judging distances when jumping
stereoscopic vision and color
color - useful for identifying objects in a moderate contrast environment
nocturnal primates do not have much color vision
thought early ancestors were ____ and ________
arboreal and nocturnal
color vision and living on ground/bipedalism came after
primates rely more extensively than other mammals on _______ __________, which means that they can be passed on from one _____ to the next
learned behaviors; generation
prosimians
biologically primitive primates (all strep. and tarsier) compared with anthropoids
anthropoidea (anthropoids)
the suborder of primates consisting of monkeys, apes and humans
strepsirrhini characteristics
often lack one or more primate characteristics
rely more on smell
brains are smaller relative to body size
many are nocturnal
variable in body size and social group size
all found in old world (african, asia and europe)
types of strepsirrhini
lorises - nocturnal, moist nose for sense of smell
lemurs - only found in madagascar, vary in body size, diet, and diurnal
haplorrhine
higher primates, consisting of monkeys and hominids (humans and apes)
rely on visual abilities and more complex social structure
almost all are diurnal
suborders of haplorrhine
tarsiiformes
platyrrhini
monkeys vs. apes and humans
m:
-tails
-smaller brains relative to body size
-spine parallel to ground
-quadruped with equal length limbs
a+h:
-no tails
-larger size
-greater intelligence
-spend more time raising young
-Y-5 molar cusp
NWM vs. OWM and examples
NWM:
-sexually dimorphic
-live in mix sex groups, but female outnumber male
-eat fruit
ex) howler monkey
OWM:
-eat fruit, leaves and small animals
-sexually dimorphic
ex) baboons
Gibbons (how they behave, interact with one another, where they are found, and what they eat)
- no sexual dimorphism
- monogamous and mate for life, no dominance
- Tropical rain forests in SE Asia (thailand, vietnam, burma, malay peninsula, etc.)
- eat fruit and sometimes leaves
- group of only adult male, female and offspring
- defend territory with loud vocalizations
Orangutans (how they behave, interact with one another, where they are found,and what they eat)
- males 2x size of females
- produce offspring more slowly than other apes, w/ birth intervals of 7.7 years
- only other primates (besides humans) that don’t have estrus
- Found in Borneo and Sumatra, tropical rain forests
- vegetarians, 60% diet is fruit
- Solitary social groups with only mother and infant, no need for males as little danger of predators
- polygamous, not enough food to support larger groups
Gorillas (how they behave, interact with one another, where they are found,and what they eat)
- found in equatorial africa, forested areas
- largest living primates
- terrestrial
- exclusively vegetarian, 85% diet is leaves due to special intestinal modifications to digest them
- small social groups, usually with one dominant male, some young males, adult females and offspring
- Silverback male makes the decisions about movement and food
Chimpanzees (how they behave, interact with one another, where they are found,and what they eat)
- found in African rainforests
- terrestrial and arboreal, hang by arms in trees
- 70% fruit diet, with leaves, seeds, nuts, insects, and small animal meat
- large communities
- mother-child bond is central
- dominance due to size, strength, intelligence and ability to form alliances
- estrus (physically showing when they are fertile)
Bonobos (how they behave, interact with one another, where they are found, and what they eat)
- females are most dominant, have multimale and multifemale groups
- sexual beings
- sexual dimorphism
- only found in rainforest of Zaire
- Diet consists of fruit, plants and very little
animal protein
Epochs/subdivisions of the Cenozoic Era
- holocene (.01-present, agriculture)
- pleistocene (1.8-.01, evolution of sapiens)
- pliocene (5-1.8, origin of genus Homo)
- miocene (22-5, divergence of apes and hominids)
- oligocene (38-22)
- eocene (55-38, first primate)
- paleocene (65- 55 mya)
Pangea
230 mya, all the continents were joined together in one land mass
Eventually split into two, called Laurasia and Gondwana
what animal can the continents can be rearranged into?
a chicken :)
evolution is a ______
mosaic, major evolutionary changes tend to take place in stage, not all at once
Adaptations for life in the trees
- 3-d spatial vision
- More important than smell - Grasping abilities
- Depth perception
- Agile body
- Good hand-eye coordination
Visual Predation Model
By Cartmill in 1974: stereoscopic vision and grasping hands evolved as adaptations for hunting insects along branches
Sussman’s Hypothesis
Primate origins might relate to eating fruit rather than insects, grasping hands are an adaptation
Eocene vs Modern Prosimians
Eocene primates were diurnal leaf and fruit eaters, similar to modern lemurs, lorises and tarsiers
Rafting Hypothesis
since the continents were already separated, hypothesis of how some species spread over multiple continents
Giagantopithecus
- Huge molar and premolar teeth in massive jaw
- As old as 9 mya, lived at same time as Homo Erectus
why did apes decline after the Miocene and monkeys flourish?
o Because monkeys outproduce apes, reproductive rates
o Environment favored monkeys, environmental changes
o Hard to match fossils with modern apes
Molecular dating
- estimating the sequence and timing of the divergence of evolutionary lines by genetic analyses
o Can predict the time at which two species split from a common ancestor
o Can test for equivalence of mutation rates with a relative rates test
Siva’s Ape/Sivapithecus
- 14-7 mya
- large jaw
- very similar to orangutans (oval eye orbital, triangular nose region, same incisors)
Toumai in Chad
- Latest find 6-7 mya, possible earliest human ancestor
- right at time of human-chimp split
- Sahelanthropus tchadensis
How could we find when humans and apes split?
molecular dating
- Sarich and Wilson
- using amino acids
- Most anthropologists estimated split of the great apes to be 15 mya
What is the only nocturnal anthropoid?
the owl monkey
human brain size and structure
- 1345 cc (largest primate brain)
- size doesn’t = intellectial ability
- brain to body ratio = 1:49
Allometry
different rates of growth for different parts of the body
- applies to the human brain
correlation between brain size and IQ
0.35, not very good
- 84% of IQ is not related to brain size
human brain summary
- Uses more metabolism than other primates
- no sexual dimorphism, however
- females score higher on verbal tests
- males score higher on spatial and mathematical tests
Human walking
- bipedalism
- weight over knees
- big toe for balance and not grasping
- vertical spine allows for balance
- short and wide pelvis
- buttocks allows for better standing and walking
human prenatal growth
fertilization –> childbirth
- embryonic (2-8 weeks)
- fetal (8 weeks - birth)
humans postnatal growth
infancy
- birth to weaning/ 3 yo
- characterized by rapid growth
childhood
- weaning till the end of growth in brain weight
juvenile
-girls: 7-10, boys: 7-12
adolescence
- girls: 10, boys: 12
- sexual maturation and quick body growth
adulthood
- end of growth
distance curve
a measure of size over time.
* Not linear. Rates change.
* Example: change in height over time
velocity curve
measure of the rates of change of growth
over time.
* Example: change in the rate of change in height over time.
* Height growth RATE decreases from age 1 till adolescence, where it briefly increases till age 14, then decreases again until adulthood.
social structure in humans
complex
- 90% of societies practice polygyny
- monogamy is predominant
What extent are the differences between humans and apes?
- both use tools
- humans use more complex tools and we depend on it more and reuse them
- we use tools to make other tools
language capabilities of other primates
- grooming (soothing and reassuring)
- vocalizations
- symbolic and open
- cannot speak like humans due to anatomy
early hominids
Sahelanthropus tchadensis
orrorin tugenensis
ardipithecus kadabba
ardipithecus ramidus
Orrorin Tugenensis
- 6 to 5.7 mya, Kenya
- Legs indicate bipedal (earliest species to show so!)
- cranial = ape
- postcranial = human
- Arboreal/time in trees
Ardipithecus Kadabba
- 5.6 mya, E. Africa
- bipedal, similar to chimp
- only teeth and fragmented bones found
Sahelanthropus tchadensis
- 6-7 mya, Africa
- Back of skull resembles an ape, base suggests bipedalism
- Small brain
- Face does not protrude
- Small canines
Ardipithecus Ramidus
- 4.4 mya, ethiopia
- Remains of 17 individuals were found, bigger canines
- Ape-like features, bipedalism due to hole in bottom of skull
- large canines
- small sexual dimorphism
Australopithecines
first line to Homo Sapiens
- Anamensis
- Platyops
- Afarensis
- Africanus
Australopithecus Anamensis
- Dates 4.2-3.8 mya, Kenya + ethiopia
- No giant canines or diastema, starting to become more like us
- Small ear holes
- Mix of apelike and modern features
Kenyanthropus Platyops
- 3.5-3.2 mya
- Small brain and ear hole, derived feature: flat face and tall cheek region
Australopithecus Afarensis
- Nicknamed “Lucy”
- 4.3 mya
- Bipedal
- Arms longer than us, looks like us more so than anything before
- Teeth bigger (esp. canines) than ours, but intermediate between apes and us, with no diastema
- Considerable climbing abilities
- Dental variation reveals sexual dimorphism
Paranthropus
- Paranthropus Aethiopicus
- Australopithecus Africanus
- Australopithecus Garhi
- Paranthropus Boisei
- Paranthropus Robustus
Paranthropus Aethiopicus
Oldest: 2.5 mya, shows primitive cranial traits
also linking it with A. afarensis.
Australopithecus Africanus
- 3.3-2.1 mya
- Reduced canines, large faces
- May be ancestral to homo sapiens
- Taung Child discovery
- small brain and U-shaped arcade
Australopithecus Garhi
- 2.5 mya
- Partial crania and upper jaw
- 450cc brain
- Similar to A. Afarensis
- Stone tools found with them!
Homo Erectus
- 1.8 mya
- brain 3/4 size of ours
- 1-1.7 mya, became first hominid to leave africa
Homo Habilis
- 2.8-1.5 mya first evidence of genus Homo
- Brain 1/2 size of modern humans, large face and teeth
- Used stone tools for scavenging animal flesh using the Oldowan tradition (flaking off stone to make point)
- gatherers and prey
Foramen magnum
The hole in the base of your skull where
your spinal cord attaches to your brain
- shows if a species would have been bipedal or quadruped
Directional Anatomy
● Anterior = towards the front
● Posterior = towards the back
● Lateral = towards the outside
● Medial = towards the inside
● Forelimb: the most anterior limb on an animal,
the arm in humans and other primates.
● Hindlimb: the most posterior limbs on an
animal, the leg in humans and other primates.
● distal - away from top/connection
● proximal - towards the top/connection
Intermembral Index
humerus length + radius length
———————————————– x 100
femur length + tibia length
growth vs. development
g - an increase in size
d - a morphological change that does not necessarily
occur with absolute growth, such as a human developing from a fetus, to an infant, to a toddler, and so on
Fusion of growth plates stages
● Stage 1: Nonunion without epiphysis
● Stage 2: Nonunion with separate epiphysis
● Stage 3: Partial union
● Stage 4: Complete union (epiphyseal scar)
● Stage 5: Complete union (no epiphyseal
scar)
Sutures
where adjacent bones of the skull meet (articulate)
Fontanelle
a space between cranial bones of an infant. The soft spot atop a baby’s head indicates the presence of a fontanelle.
cranial vault suture scores
the lower the number, the least unified they are
External factors that may impact skeletal
development:
- Nutritional History
- Disease
- Access to resources
- Stress
- Environment
Most common methods used to estimate
skeletal age:
● Suture Obliteration
● Epiphyseal/bone Union
● Dental Age Estimation (formation and
eruption)
what species did the famous “black skull” belong to
paranthropus aethiopicus
what species did the famous “Zinj (aka Nutcracker man)” belong to
paranthropus boisei
what was the first species in the Homo genus?
Habilis
Homo Habilis
o Smaller teeth than A genus but bigger than us
o Large brain, avg. 630 cc
o Stone tools
o Used Oldowan tradition: relatively simple chopping tools made by striking several flakes off a rounded stone to give rough edge
o little evidence of being hunters, mainly gatherers
single species hypothesis
A model of pilo-plesitocene hominid evolution that stated only one species of hominid was present at any one time.
theories as to why we become bipedal
tool use model
predator avoidance
reproductive success model
food acquisition
temperature regulation
climate change model
advantages to having a larger brain
more mental capacity/increased ability to learn
disadvantages to having larger brain
more time in adolescence
larger skull has to pass through pelvis at birth
Australopithecus characteristics
● Narrower cheek bones
● No facial dishing (cheekbones go
backwards a bit)
● Little to no sagittal cresting
● Smaller cheek teeth than Paranths, but
large compared to chimps and
humans
● Premolars look more like ape-like
● Smaller brains: 370-430 cc
Paranthropus characteristics
● WIDE cheek bones
● Facial dishing (cheek bones come
forward a bit)
● Saggital cresting
● HUGE cheek teeth
● Premolars are wider and molarized
(look like molars)
● Bigger brain: 410-530 cc
what defines a hominin?
bipedalism
increase in cranial capacity
parabolic dental arcade
