Hominid Reproductive Strategy/Evolution

Question 1

sectorial canine complex

Answer 1

A specialized dental structure seen primarily in certain extant apes and some early human ancestors. This complex typically includes the canine and first lower premolar, or the sectorial/honing premolar, and is used for sharpening the canines. It often indicate male-male competition.

Question 2

canine honing

Answer 2

The sharpening of the canine in some extant and extinct hominids and hominoids.

Question 3

the “survivorship balance”

Answer 3

The balance between females genetically choosing males with large ornaments that would make them reproductively successful but their ornaments can only get so large to keep themselves alive creating a positive feedback loop.

Question 4

reproductive value (measured at birth)

Answer 4

Reproductive value ,measured at birth, quantifies reproductive value using maximum life potential (how long can you reproduce), how long until sexually mature, birth space, and reproductive rate.

Question 5

sperm plug

Answer 5

A reproductive strategy where sperm will coagulate, creating a sperm plug to block the sperm of competing males.

Question 6

sperm mid-piece

Answer 6

The middle piece of sperm contains numerous mitochondria to provide energy to the sperm for their movement inside the female reproductive system. (The powerhouse of the sperm)

Question 7

sperm competition

Answer 7

Sperm competition occurs whenever females have multiple mates and ejaculates from different males overlap and compete for fertilization. Variable that affect sperm competition are sperm coagulation, the sperm mid-piece, and penis complexity.

Question 8

prolactin (in Finches)

Answer 8

Prolactin in Finches increase brooding behavior, essentially making them more inclined to take care of their offspring.

Question 9

prolactin (in human males)

Answer 9

Too much prolactin can interfere with function of testicles which decreases testosterone

Question 10

dopamine

Answer 10

Dopamine gives motivation for all basic needs. The reason you do anything is because of a dopamine response. Dopamine is created in the ventral tegmental area (VTA) which is located in the midbrain, it controls diverse behavioral repertoire, including reward processing. It is the part of the brain the produces, and disperses dopamin.

Question 11

serotonin

Answer 11

apes and humans decreases aggression by regulating moods, natural “feel good” chemical

Question 12

acetylcholine

Answer 12

Humans have a decrease in this neurotransmitter compared to apes, but higher dopamine levels. However, it is still important for memory, attention, learning, arousal, and involuntary muscle movement. This creates an external drive for social conformity, community, decreased aggression, and a sensitivity to environment and social cues ultimately leading to social monogamy.

Question 13

neurotransmitter

Answer 13

Neurotransmitters are endogenous chemicals that allow neurons to communicate with each other throughout the body. They enable the brain to provide a variety of functions, through the process of chemical synaptic transmission. The neurotransmitters in humans promote fat and sugar seeking behavior.

Question 14

foxP2

Answer 14

This gene provides instructions for making a protein called forkhead box P2, which appears to be essential for the normal development of speech and language.

Question 15

caudate nucleus

Answer 15

Upper part of corpus striatum in cerebrum of the brain. Functions include planning the execution of movement, learning, memory, reward, motivation, emotion, and romantic interaction

Question 16

putamen

Answer 16

The outer part of the lentiform nucleus of the brain. It is involved in learning and motor control, including speech articulation, language functions, reward, cognitive functioning, and addiction

Question 17

ventral striatum

Answer 17

A cluster of interconnected nuclei that form part of basal ganglia (involves nerve cell bodies and smooth movement), very important in processing of reward and influence motor output to guide behavior.

Question 18

cortical-striatal reward pathway

Answer 18

The reward pathway of the brain is connected to areas of the brain that control behavior and memory. Rewards pathways give dopamine responses for behaviors that increase survival, eating, sleeping, etc… In humans, due to are very large brains, humans have a hugely expanded range for what gets “plugged into” our reward pathway. This allows a dopamine response for extremely complex behaviors.

Question 19

lactational amenorrhea

Answer 19

Process by which breastfeeding temporarily prevents pregnancy from occurring

Question 20

ovulatory crypsis

Answer 20

Concealed ovulation or hidden estrus means females show no signs of fertile or time of ovulation physically, humans are one of the only species that exhibit this characteristic. Female humans only primates with permanently enlarged breasts.

Question 21

dart frogs

Answer 21

Dart frogs are a good example of a K-selected species. The carry their offspring on their back (child care), have few offspring (relative to other frogs), and an increased lifespan. These are some of the main factors that make a species K-selected. All of these tendencies in reproductive strategy are also seen in humans, as they are extremely K-selected.

Question 22

horned toad adaptive suite

Answer 22

Ant specialists that requires a large stomach-to-body ratio, replace of rapid flight (too large to move fast) with armor and crypsis (camouflage). In turn this requires long periods of motionlessness which increases tolerance for variance in body temp, creating a large clutch size.

Question 23

simple versus complex penis

Answer 23

Whether a penis is simple or complex is determined by the reproductive strategy that a species uses. Primates with simpler penises tend to be monogamous (only have one partner) or polygynous (mate with only a few partners). The more complex penises belong to primates like bushbabies and lemurs, who mate with many partners in their lifetime. These complexities of the penis are typically sensory receptors that play a role in copulation.

Question 24

How does canine eruption differ in humans and chimpanzees?

Answer 24

The canine is a social tooth, chimps have very pronounced canines (male to male competition) while humans are absent (male to male cooperation)

Question 25

Name several elements favored by females in mate choice involving provisioning.

Answer 25

Active provisioner (Biped), Reduced Canines (increased cooperation, i.e. time spent on food, not male competition), and Adequate body mass (Resist predation)

Question 26

Name several elements favored by males in mate choice involving provisioning.

Answer 26

Stimulated lactation, concealed ovulation, continuous sexual proceptivity, parenting skills (IQ), and reduced body mass

Question 27

What is the average birth space in chimpanzees and gorillas? In orangutans?

Answer 27

Average birth space in chimps/gorillas: 3-5 years
Orangutans: 7-8 years

Question 28

Name three elements of the adaptive suite of a horned toad that are dependent upon its
primary diet.

Answer 28

increase in stomach/body size ratio, increase in armor, increase in clutch size

Question 29

Describe the adaptive suite of an early hominid engaged in a provisioning strategy.

Answer 29

bipedality, loss of social canine complex, and ovulatory crypsis (the big complex chart about how homo adapted)