ANBI 100

aspect of sexuality that addresses WHY, or for what function, a trait evolved

Aspect of sexuality that addresses underlying mechanisms that control for a trait

a form of natural selection that acts differently on the sexes

sexual selection that favors the ability of one sex
i.e. male-male competition

sexual selection that favors traits in one sex which attract the other
i.e. female mate choice

occurs when genetic/reproductive interests of females and males diverge
can lead to one sex having an advantage, or an arms race between the sexes
i.e. infanticide

a trait that is specially suited for a particular fx in a particular env't

conditions for evolution by natural selection

differential reproductive success of individuals over multiple generations based on the heritable differences between them; aka non-random selection

examples of sexually selected traits (5)

Features that result from a common ancestry

Specialized traits that distinguish species from its last common ancestor

Common features that are not the result from a common ancestry

when distantly related species evolve the same/similar trait as an adaptation to same ecological pressures

characteristics of mammals (6)

major categories of primates

traits that have not changed from their ancestral states

Found in southeast Asia
Share some features with both prosimians and anthropoids.
Sometimesclassified in suborder Prosimii, sometimes in suborder Haplorhini
Nocturnal, Solitary
The only carnivorous (insectivorous) primate!

prosimian beh'ral characteristics (8)

adaptations that differ from the ancestral state

anthropoid characteristics (5)

platyrrhines

catarrhines

arboreal, frugivorous/gumivorous/folivorous/insectivorous/seed-eaters, 3 Families: Callitrichidae, Cebidae, Atelidae

subfamilies Colobinae/Cercopithecinae, some species terrestrial, some have menstrual cycles and sexual swellings

Hylobatidae/Pongidae/Hominidae, no tail, large body size, short trunk, flexible shoulder joint

arboreal brachiators, fruit-eaters, "lesser apes," sexually monomorphic, socially monogamous, & territorial

anthropoids, arboreal scramblers, found in Asia, fruit-eaters, sexually dimorphic, often solitary

terrestrial knuckle-walkers, largely frugivorous, fission-fusion communities

small, one-male groups, herbivorous and frugivorous, mountain and lowland species

portion of land that is actively defended

entirety of land used by a troop

direct costs of group living (5)

indirect side effecs of group living (3)

solitary social system, occurs when females assemble based on spread out resources

social systems that consist of multiple members, i.e. pair + offspring, harem/bachelor groups, MM-MF, and fission-fusion

polygynandrous species

temporary association; coalescing and splitting based on availability of food

ratio of males to females

ratio of males to presently breeding females

extreme is forced copulation; more commonly shows up in primates via intimidation and aggression

what are the 3 levels sexual selection acts on?

mating contests and mate choice are examples of what level of sexual selection?

copulatory plugs, sperm competition, and mate guarding (sometimes) are examples of what level of sexual selection?

infanticide is an example of what level of sexual selection?

female counter-strategies to infanticide? 5

most muscular tube in the male body

what is the most likely reason for such complexity in primate penile morphology?

tip of the penis

species with the most derived penile morphology; distal penis is filiform w/no glans, likely evolved from sperm competition and to accomodate female swellings

mechanism for detecting pheromones

humans and our extinct ancestors after the split from the last common ancestor with chimpanzees

any member of the family Hominidae, including all australopithecines and the genus Homo, walks upright

any member of the superfamily Hominoidea, including humans, all living apes, and numerous extinct ape and humanlike species from the Mioccene, Pilocene, and Pleistocene epochs

• Date from 4.2 million years to 1.2 million years ago
• Mix of bipedal locomotion and ape-like features
• Small brained creatures with lots of sexual dimorphism in body mass and a little in canine size
• Some species had specialized dietary adaptations (Paranthropines)

Remains found at Lake Turkana, primitive biped (suggested by knee and ankle bones) living in streamside forests
Had large molars, thick enamel, and reduced canines; its U-shaped dental arcade is more similar to chimps and gorillas
Dated to 4.2-3.9 mya

remarkably complete skeleton, best-known australopithecine, found in East Africa 4-3 mya, fossils indicate habitats ranging from woodland to dry savanna, and that there was pronounced sexual dimorphism

species represented by the Lucy fossil, one of the earliest bipeds

individual with a flatter face than earlier australopithecines. Nomenclature is questioned.

possibly earliest australopithecine to use tools (2.5 MYA)

“Southern ape ofAfrica”
• Found in South African cave and cliff deposits in a cement like matrix (breccia).
• Probable descendant of A. afarensis that migrated south
Taung Child, 3 yr old, discovered 1924

Proper term for robust Australopithecines

• Anatomically specialized for hard-object diet: nuts and tough fibers. Also ate some meat.
• Maximized muscles of mastication produced flared zygomatic arches and postorbital constriction.

-Small brained animal with prognathic face and large anterior teeth.
-Primitive, possible ancestor of later robust individuals who share a set of traits with this species.
-Locality: Lake Turkana

• Robust individual who shared some features with A. aethiopicus.
• Highly specialized with a wide East African distribution.
• Locality: Kenya, Tanzania, Ethiopia

• Discovered in 1938 ata time when scientists doubted early hominids lived in Africa.
• Robust individiuals but smaller than A. boisei.
• Locality: Kromdraai, Swartkrans, Drimolen

2 outcomes of >1 species occupying the same habitat

Defining traits of the genus Homo (4)

“Handy man” since found in association with stone tools
Much larger brain? ~50% > compared to Australopithecines
Findings restricted to Olduvai Gorge

-Consist of cores (river cobbles) or source material from which flakes are removed by striking with a hammerstone
-Include flakes or small fragments, extremely sharp and useful in butchering meat or slicing through animal hide.

• A major shift in hominid lineage took place about 1.8 MYA from H. habilis
• Bigger bodies
• Longer legs
• A modern-like gait
• A larger brain and uniquely shaped skull

used Acheulean tools, earliest evidence of controlled fire, diet included both plants and animals to sustain brain size and body size increase

Have a blend of H. erectus and H.sapiens traits (mosaic evolution)
Robust bodies and large faces
Larger brain, more sapiens-like skull
Large, arching brow ridge
Large nasal aperture
Thick-boned cranial vault
Inflated cheeks

Larger cranium than modern humans, Short limbs, short fingers, but broad chests and broad pelvis

Direct ancestors of modern Europeans, contributed some genes to modern human populations were completely replaced by modern humans without contributing any genes to contemporary populations

Behavioral traits include making stone tools, Coping with cold, Hunting and subsistence, Cannibalism, Burying the dead, Ritual and symbolic performance and expression

size, sexual composition anad spatiotemporal cohesion of a society

3 aspects of a social system

pattern of social interactions and social relationships of members of a society

5 reasons to form groups

composition of a social group

determines the number of sexual partners that individuals have

social system in which individuals forage separately to increase efficiency, but sometimes sleep near each other

social system in which individuals feed, travel, and sleep together

system in which individual females occupy very large and exclusive ranges where other females are not tolerated. The best option for males is to pair up with a single female

characteristics of monogamy (6)

system in which a female lives in a reproductive or social unit with more than one male

reproductive skew, SSR, OSR, and female choice influence the intensity of _______________

canine dimorphism is dependent upon what type of ratio?

body size dimorphism depends on what ratio?

sex differences in schedule of development

aspects of morphology that reliably indicate male survival ability, pathogen resistance, etc.; they also indicate how a male's offspring will do

examples of handicaps

Male reproductive tactics (5)

stage in which dominance is established via aggressive competition among individuals

stage in which members arrange themselves into a transitive hierarchy based on the outcome of the many individual contests among individuals

relationship between individuals in a group, not inherited genetically

what conditions must be in place for animals to fight?

short-term association of 2 or more males

long-term coalition of 2 or more males

a male and female who maintain an exclusive relationship, highly variable in duration, usually to facilitate mating opportunities and ensure fertilization

extreme is forced copulation; more common is intimidation, harassment, and aggression directed at female to induce her to copulate willingly

adaptive strategy among non-human primate males in which they kill a female's infant in order to induce ovulation and bring her out of lactational amenhorrea sooner

most muscular tube in the male body

provide transport medium (fluid) for spermatozoa during ejaculation

5 potential hypotheses for evolution of male genitalia

occurs in female spider monkeys, has a function in scent marking/attracting mates, in fission-fusion structure, similar to fx of swellings

filtering mechanism of females that is 1-2 cm in humans, function is not entirely understood

ovarian end of oviduct

removal of sperm plasma membrane

a sperms' rapid figure-8 movements that may help to break away from the pack

escape of the acrosomal contents

Characteristics of the primate order?