Lectures 1 & 2: Intro to Evolutionary Anatomy

Question 1

What is meant by functional anatomy?

Answer 1

It is the study of anatomy as it relates to function. A functional explanation of a structure wil focus on what a structure does and how it is used by the organism it is attributed to.

Question 2

What is evolutionary anatomy?

Answer 2

The study of anatomy as it relates to how organisms are related to each other from a phylogenetic perspective. An evolutionary explanation of a structure will focus on how changes over time, resulting from selective pressure and other evolutionary processes have led to observed similarities and differences among organisms

Question 3

What is biological evolution?

Answer 3

Descent with modification

Question 4

What is taxonomy?

Answer 4

A science, concerned with identifying, describing, grouping, and then naming organisms in a systematic fashion
**How we classify organisms based on observed characteristics

Question 5

What is phylogeny?

Answer 5

Diagram that illustrates a hypothesis about evolutionary relationships within and between groups of organisms.
Phylogenies are constructed using methods of phylogenetic inference to evaluate observable heritable characteristics

Question 6

What is cladistics?

Answer 6

Essentially unites taxonomy and phylogenetics to create a method of classification of organisms that is based on shared characteristics that are a result of common descent from an ancestral form

Question 7

What are the 4 processes of evolution?

Answer 7

1) Natural selection
2) Gene flow (migration)
3) Genetic drift
4) Mutation

Question 8

What are the 6 examples of evidence for evolution provided in class? (Objective says to know 5 of these)

Answer 8

• All life is related
• Organisms form natural groupings
• Species are dynamic
• Vestigial structures
• Biogeography
• Fossil record

Question 9

What does “All life is related” as evidence for evolution suggest?

Answer 9

Organisms share a universal genetic code and have a common genetic make up

Question 10

What does “Organisms form natural groupings” as evidence for evolution suggest?

Answer 10

Molecular, anatomical and embryological data support relationships among species

Question 11

What does “Species are dynamic” as evidence for evolution suggest?

Answer 11

Biological species concept defines a species as an interbreeding population, but there are many cases where it is difficult to define a species this way

Question 12

What does “vestigial structures” as evidence for evolution suggest?

Answer 12

Organisms often exhibit non-functional or non-adaptive features

Question 13

What does “Biogeography” as evidence for evolution suggest?

Answer 13

Distinct patterns of species distribution cross the planet tells a story of historical processes that have influenced change over time

Question 14

What are the 3 conditions for natural selection to occur?

Answer 14

1) Must be variation in a trait, or traits, within a population
2) Variation must be heritable
3) Variation must correlate with fitness (reproductive survival and success)

Question 15

What is meant by “variation”?

Answer 15

Individual organisms within a population vary from 1 another in observable ways; molecularly, anatomically, behaviorally, etc…

This variation provides the “raw material” of evolution that natural selection works on to produce change over time

Question 16

What is heritability?

Answer 16

Something that can be passed to offspring via genes.

Variation that has a genetic base is heritable

Question 17

What is reproductive success?

Answer 17

An individual’s reproductive success is measured by the number of survival offspring that is has

*more serving offspring=higher reproductive success

Question 18

What is biological adaptation? Example?

Answer 18

The ability of an individual organism or a population of organisms to successfully negotiate the pressures of a given environment in order to survive and reproduce

Giraffes with long necks have greater fitness than giraffes with short necks because they can better reach food

Question 19

Why is natural selection the best model for explaining adaptiveness?

Answer 19

Natural selection produces a “good fit” between species and environments they inhabit

Natural selection has been observed in wild and simulated under controlled conditions for a very long time aka artificial selection

Question 20

What are the 4 limits of natural selection?

Answer 20

1) Selection can only act on existing variation
2) Selection will only improve fitness
3) physical and developmental aspects of an organism constrain natural selection
4) Not all change is due to natural selection (genetic drift is example)

Question 21

What is adaptionism?

Answer 21

The idea that every feature exhibited by an organism is the result of evolution under natural selection

Question 22

What are the shortcomings of “adaptionism”?

Answer 22

• What about other mechanisms?
• What about characteristics that appear out of sequence or have no apparent adaptive value?
• It can be difficult to test for adaptation, therefore difficult to disprove that is has occurred.
• How do we currently identify relevant traits?

Question 23

What are homologous structures?

Answer 23

Shared characteristics of organisms that were inherited from a common ancestor

I.e. All tetrapods have 4 limbs

Question 24

What are analogous structures?

Answer 24

Shared characteristics that arise because of similar selective pressures, thru parallel or convergent evolution

Characteristics that are similar in organisms that have separate evolutionary lineages

I.e. Bird and bat wings

Question 25

What is parallelism?

Answer 25

Selection has exerted similar pressures on two closely related organisms

Question 26

What is convergence?

Answer 26

Selection has exerted similar pressures on 2 distantly related organisms

Question 27

What is a symplesiomorphy?

Answer 27

Shared primitive characteristics

Question 28

What is a synapomorphy?

Answer 28

Shared derived characteristic that is assumed to be present in the most recent common ancestor

Question 29

What is a plesiomorphy?

Answer 29

Ancestral state

Question 30

Explain the functional perspective of the human spinal column

Answer 30

1. Protects spinal cord 2. Provides structural core for attachment of head, thorax and limbs 3. Transmits the weight of the upper body to lower limbs 4. Accommodates bipedal/upright postures and locomotion (due to its unique curvature)

Question 31

What are the similarities between the human and chimpanzee spinal column anatomy?

Answer 31

1. Protection of spinal cord | 2. Rigid structural core for head and limbs

Question 32

What are the differences between the human and chimpanzee spinal column anatomy?

Answer 32

1. Spinal curvatures that accommodate upright posture | 2. Obligate bipedalism versus straighter spinal column that accommodates quadrupedal knuckle-walking

Question 33

What does the evolutionary perspective show?

Answer 33

Common features that are evidence of common ancestry Differences indicate key selective pressures that led to adaptations for upright posture and bipedal locomotion in humans

Question 34

What has lead to the species diversity that we observe?

Answer 34

Process of descent with modification (biological evolution)

Question 35

Squirrel example of descent with modification

Answer 35

80% = sparsely furred tails 20% = bushier tails Over time, climate becomes much colder Bushier tails tend to survive longer and produce more offspring Later generations 70% = bushier tails 30% sparsely furred tails

Question 36

Savannah grazers example of descent with modification

Answer 36

``` 50% = longer neck vertebral segments 50% = lack gene ``` Over time, food becomes scarce and must browse from trees Longer neck leads to increase in survival and reproduction rates Later generations 95% = longer neck

Question 37

What is intersexual selection and example

Answer 37

Favoring traits in one sex that attract the other sex Bird coloring in males to attract females Can make males more susceptible to predators

Question 38

What is intrasexual selection and an example?

Answer 38

Favoring the ability of one sex, typically males, to directly compete with one another for fertilization opportunities Some male primates have much larger bodies than females and very large canines Biggest males with largest teeth can drive other males away and gain relatively exclusive access to females

Question 39

Define microevolution

Answer 39

Occurs when there are changes in gene frequencies in a population from one generation to the next

Question 40

Define macroevolution

Answer 40

Occurs when there is a descent of different species from a common ancestor over many generations

Question 41

Among the 15 characteristics that unite members of the order primates are: Housing of the middle ear in the thick ____________ bone Emphasis on vision making the orbits ________ and ________ Frontally directed orbits reinforced by a ______________

Answer 41

Petrosal Convergent and frontated Post-orbital bar

Question 42

Among the 15 characteristics that unite members of the order primates are: ___________ vision, allowing for enhanced depth perception _____________ emphasis on smell Grasping hands and feet with ________ first digits

Answer 42

Stereoscopic Decreased Opposable

Question 43

Among the 15 characteristics that unite members of the order primates are: ______ sitting posture ___________ bipedalism ___________ brain size

Answer 43

Erect Facultative Increased

Question 44

Among the 15 characteristics that unite members of the order primates are: __________ life history stages __________ social behavior and communication ___________ habitat ____________ distribution (location)

Answer 44

Prolonged Complex Arboreal Tropical

Question 45

Among the 22 characteristics/trends that unite the genus Homo (humans) are: Relatively and absolutely _______ brain size ____________ developed intellect, awareness, consciousness, etc. ________ facial expressions

Answer 45

Large Highly Diverse

Question 46

Among the 22 characteristics/trends that unite the genus Homo (humans) are: __________ use of language ___________ life history __________ bipedalism and its anatomical correlates

Answer 46

Habitual Extended Habitual

Question 47

Among the 22 characteristics/trends that unite the genus Homo (humans) are: ___________ arch of the foot ___________ of hair, ___________ sweating, ______ subcutaneous fat __________ of the face, __________ of tooth size

Answer 47

Longitudinal Reduction; increased; more Shortening; reduction

Question 48

Among the 22 characteristics/trends that unite the genus Homo (humans) are: __________ enamel Food ________ and _________ Extensive _________ culture

Answer 48

Thickened Sharing; production Material

Question 49

Among the 22 characteristics/trends that unite the genus Homo (humans) are: Use of ___________ Use of __________ Complex _______ behavior and organization

Answer 49

Clothing Fire Social

Question 50

Among the 22 characteristics/trends that unite the genus Homo (humans) are: ______ division of labor as well as extensive division of labor within society Long-term ______ bonding Pursuit of _____________ our of context of reproduction _______ of the habitat

Answer 50

Gender Pair Sexual behavior Reshaping

Question 51

The 4 complexes of traits that have contributed to the unique adaptive strategy of humans are: ________ bipedalism ________ brain Ability to sustain high ___________ activities A life history strategy that depends on complex ________ relationships

Answer 51

Habitual Enlarged Metabolic Social

Question 52

In the shift from facultative to habitual bipedality, changes occurred in the vertebral column, femoral angle, foot, and pelvis. What were these changes?

Answer 52

The vertebral column gained curvature and successively larger vertebrae from cervical to lumbar Femoral angle increased to allow humans to place foot directly beneath center of mass Foot became flattened and more platform-like Pelvis gained larger lateral shape vs. primates who had longer iliac blade

Question 53

Who uses oxygen more efficiently, Humans or Primates?

Answer 53

Humans use oxygen 75% more efficiently

Question 54

What aspect of forearm anatomy allows for stronger movement and dexterity in humans?

Answer 54

Longer flexor muscle of the thumb

Question 55

In comparing the skulls of hominin vs. other hominids, hominin has: ``` _________ brain size Canine __________ __________ enamel __________ face _________ in masticatory mass ```

Answer 55

``` Increased Reduction Thickened Shortened Decrease ```

Question 56

The general behavioral trends of the genus Homo include: Ever _________ tool complexity Incorporation of scavenged and/or hunted _____ food, and later dependence on _________ _______ cultural practice

Answer 56

Increasing Flesh; cooking Complex

Question 57

The size dimorphism in the genus Homo suggests what from gorillas to chimps to humans?

Answer 57

Gorillas: single male + multifemale social units Chimps: multimale + multifemale units Humans: serial monogamy (humans)

Question 58

Describe the primary craniofacial differences between the Australopithecines and Paranthropines in terms of tooth enamel, brain size, dentition trends, and cranial structure

Answer 58

Australopithecines: Thick enamel, chimp-like brain size, generally large dentition, similar cranial structure among species until sediba who had projecting nose and smaller teeth/chewing muscles Paranthropines Massive, thickly enameled molars, slightly larger brain size, molarized premolars with greatly reduced anterior dentition, massive trophic cranial structures leading to increased specialization for food processing

Question 59

What makes a primate a primate? Presence of a __________________ in the skull Orbits are both ____________ and _____________ Hands are ______________, often rotated, and occasionally opposable thumb Feet are ___________, often with rotated toe (except humans) All primates have ________

Answer 59

Post-orbital bar Convergent; frontated Divergent Divergent Nails

Question 60

In comparing lemurs/lorises vs. monkeys/apes: Lemurs have split nose with ______ patch; apes have _____ nose Lemurs have post-orbital bar with _______, but beyond the bar is ______ in apes Lemurs have a larger and more complex _______ than apes, representing the apes increased dependence on vision Lemurs have a tooth ______, apes do not

Answer 60

Wet; dry Opening; closed Snout Comb

Question 61

In comparing New World monkeys to Old World monkeys: New World have ______ nose with nostrils on the ______, Old World have nostrils toward the ______ OW have lost one _______. NW have a dental formula of 2:1:3:3, OW have 2:1:2:3. Humans share their dental formula with the _______ monkeys _______ monkeys have prehensile tails (hang on things)

Answer 61

Flat; sides; front Premolar Old world New world

Question 62

In what two ways are all monkeys different from apes?

Answer 62

Monkeys may/may not have tails, but NO apes have tails Apes generally have larger and more complex brains - more gyri and sulci and differentiation of function by hemisphere