Primate behavior and origins (ch 8 intro)Part 1 from Monday

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Today*Midterm info

*Look at the apes

*Primate behavior

*Origins

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Midterm882-E Scantron35 total questions25 multiple choice6 true/false

4 short answerTen possible short answer questions online

Five questions will be on the testMust answer FOUR of the five questions

ContentChapters 1 through 8 (where we end on Wednesday)

Mostly chapters 5-8 material

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Essay in-text citationDon't do this:

"Jurmain et al posit the existence of a common ancestor between humans and the other great apes (Jurmain et al., 2013: 135). This would mean that behaviors seen in modern populations of chimpanzees were probably employed by our common ancestor (Jurmain et al., 2013: 135). This means that the limited grasp of symbolic thought evident in chimpanzees (Jurmain et al., 2013: 135) was possible 6-7 mya when humans are thought to have diverged from the rest of the apes (Jurmain et al., 2013: 136). The evolutionary history of the hominins (Jurmain et al., 2013: 137) is the main subject for the next chapters of (Jurmain et al., 2013: 140) the (Jurmain et al., 2013: 140) book."

Instead do this:

"Jurmain et al posit the existence of a common ancestor between humans and the other great apes. This would mean that behaviors seen in modern populations of chimpanzees were probably employed by our common ancestor (Jurmain et al., 2013: 135). This means that the limited grasp of symbolic thought evident in extant chimpanzees was possible 6-7 mya when humans are thought to have diverged from the rest of the apes (136). The evolutionary history of the hominins is the main subject for the next chapters of the book (140)."

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RecapRecall: want to explain primate behavior in an evolutionary framework

Ask: how do the behaviors we observe contribute to evolutionary fitness?

Primatologists answer this question using behavioral ecology -see behaviors as the product of interconnecting biological components (see previous slide set)-behaviors we see in primates increase reproductive success (natural selection explains how behaviors arose)

Primates are highly social animals-importance of socializing results in various behaviors evident in primate groups

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Reproductive strategiesBehavior favored by natural selection to increase an individual's reproductive success

K-selection - an adaptive strategy with fewer offspring and increased parental investment

E.g., birds, wolves, elephants

r-selection - more offspring coupled with less parental investment

E.g., mice

Primates are K-selected and the mother plays a larger role in raising offspring

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Primate reproductive strategiesPrimates are K-selected and the mother plays a larger role in raising offspring

Females - strategy: maximize available resources given energetic demands of being female

Males - strategy: produce as many offspring as possible

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1. Primate grouping patterns1. Single female and offspring - Basic social unit (e.g., orangutans)

2. Monogamous family group - rare in nonhuman primates

3. Polyandrous - single female: multiple male (e.g., marmosets)

4. Single male and multiple female - single male: multiple female (e.g., gorillas)

5. Multiple males and multiple females - no stable bonds (e.g., baboons)

6. Fission-fusion - size and composition change relative to activities and patterns (e.g., chimpanzees)

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Communication-unique acts conveying information to another individual/group

-used by all nonhuman primates

-vital to social living

Include: facial expressions, displays, vocalizations, interactions

Automatic - responses not under voluntary control (e.g., chimpanzee body hair rises when excited)

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CommunicationAggressive-conflicts arise due to competition for resources-dominant females observed harassing lower ranking females

Affiliative-amicable behavior promoting group cohesion-grooming

Importance of affiliative behavior:-individuals support each other against outsiders-status is often enhanced through alliances

Displays - repetitive behaviors broadcasting the emotional state(s) of an individual

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Grooming-picking through fur to remove debris

-social grooming reinforces social relationships

-seen in various social contexts

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Language and communicationHumans use language as a set of symbols that refer to objects, other people, concepts, events, etc.

i. Arbitrary system - no inherent connection between a symbol and whatever it refers to (what the symbol might represent)

ii. Symbols can be particulated and recombinations of these parts generate new/different meanings

iii. Set of symbols can be used to refer to past and future events

i.-iii. are key features of human language

-supports the view that our reliance on language emerges from our ability to think symbolically

*Language and other apes

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Early primates and hominins

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Paleoanthropology-study of early humans. -It is a diverse multidisciplinary pursuit attempting to accurately explain the human origins

-Includes locating early hominin sites, collecting faunal remains, and artifacts

Paleoanthropologists reconstruct the anatomy, behavior, and ecology of our ancestor

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*Primates in the Paleocene (65-56 mya)Key group(s): Plesiadapiforms

-Earliest primates;

Location: N. America

Ancestral traits: sm body, snout (olfactory?)

Derived traits: opposable thumbs, flat molars (fruit diet?)

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*Eocene 56-33 myaKey group(s): Adapids and Omomyids

-wide geographic distribution (Europe and N America)-mostly extinct by the end of the Eocene-Unclear connection with modern primates

Omomyids: more 'primitive'; smaller, likely nocturnal, etc

Adapids: more derived; larger, frugivore (diurnal?)

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*Oligocene 33-23 mya~Old World monkeys location: Fayum*ApidiumAncestral: squirrel-sized; Derived: arboreal

*Aegyptopithecus Anc: smaller brain ;Derived: howler monkey size-closely related to ancestors of the two major groups of Old World anthropoids

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Miocene 23-5 mya Key group(s): Proconsul and Sivapithecus-More like apes-Mostly large-bodied-No direct ancestors to modern primates-Continental drift altered climatic patterns + new migration routes

Found in Africa, Europe, and Asia

*Genus ProconsulAfrican forms 23-14 mya

*Sivapithecus Asian forms 15-7 mya - largest; most variable group including (derived facial features similar to living orangutans

Hominins

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-all bipedal hominoids back to the divergence from African great apes

~7-6 mya split from chimpanzees and bonobos

-emerged and stayed in Africa until later Homo

Defining hominin characteristics-bipedal locomotion, tool-making behavior, larger brains

Mosaic evolution - these characteristics evolved at significantly different rates (not at same time)

Defining Characteristics of Hominins

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Larsen 2010 pp227

1. Bipedalism2. Distinct dental pattern3. Tool-making behavior4. Large brains

Bipedalism - Defining Hominin feature* Habitual: primary + most efficient locomotion used by Hominins* Obligate: Hominins are committed to bipedalism* Stable Center of Gravity* Balance* Weight transmission* Energy efficiency

Pelvis is comparatively much shorter and broader and extends around to the side, stabilizing the line of weight transmission from lower back to hip joint

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