Midterm 2 Flashcards
The main levels of taxonomic hierarchy?
Kingdom, Phylum, Class, Order, Family, Genus, Species
*The full classification of our species
- Kingdom: Animalia
- Phylum: Chordata
- Class: Mammalia
- Order: Primates
- Family: Hominidae
- Superfamily: Hominoidea
- Tribe: Hominini
- Genus: Homo
- Species: sapiens
*the taxonomic classification of the primates
SEE picture on phone
Explain the trade-off between number of offspring and investment in offspring
The trade-off between number of offspring and the investment in offspring is a key concept in evolutionary biology, as it involves a balance between quantity and quality of offspring. Species that produce more offspring (r-selected) may have lower individual investment in each one, while species with fewer offspring (k-selected) tend to invest more resources into ensuring their survival and success
Concept of life history
How different stages of growth and development are typically distributed across the lifetime of an animal
- How much time is spent as an infant?
- How much time is spent growing?
~ When do teeth erupt (weaning; independence from mother)
~ When do bones fuse (adult size)
- When does reproduction start!?
*Generally thought about as a trade-off
What does it mean to say a primate species has a slower life history vs. a faster life history?
Life history theory predicts that certain strategies are optimal in certain situations
-Grow quickly, reproduce early, be small
- Grow slowly, reproduce late, be big
Primates have a slower life history compared to other mammals, which allows for increased opportunities for learning and social interactions. This prolonged development period likely contributed to the development of complex social structures and behaviors in hominid populations.
What biological features do primates share?
- Grasping hands and feet (5 fingers and toes; thumb and “big” toe position)
- Nails instead of claws (distal phalanx)
- Pronation and supination ability (radius and ulna; tibia and fibula)
- Binocular and stereoscopic vision (eye orbits facing forward)
- Color vision in cones (ability to see red; for fruit? for sex?)
- Reduced reliance on smell (reduced snout)
Why are social groups and social behavior so important for most primates?
- Safety and defense (strength in numbers)
- Other individuals around to do stuff; potential for cooperation; potential for exploitation
- Food gathering
- Pool of potential reproductive partners
- Decreasing predation risk
- Easy to defend good food sources
In what ecological niche do we think the earliest primates evolve?
Tropical rainforests
What biological features are present in the strepsirrhines that are more primitive than the haplorhines?
means “wet nose”
- lacks color vision
- rely on smell (large snout)
- nocturnal
- grooming claw
- partially open orbits
- mandible with suture at midline
What biological features are more derived in monkeys and apes than in strepsirrhines?
means “dry nose”
- color vision
- small snout
- diurnal
- no grooming claw
- closed orbits
- no mandible with suture at midline
Platyrrhines dental formula
2.1.3.2-3/2.1.3.2-3
Catarrhines dental formula
2.1.2.3/2.1.2.3
What is the difference between an ape (a hominoid that is not a hominin) and a monkey (a catarrhine this is not a hominoid)?
The main distinction between apes and monkeys lies in their anatomical features, with apes having no tails and larger bodies compared to monkeys
Pronograde vs. orthograde
A pronograde body plan means that an animal moves with its body parallel to the ground, with limbs extending out to the sides. This type of body plan is common in quadrupeds like dogs and cats, allowing for greater stability and agility while moving on all fours.
- in quadrupedal locomotion, the body is this
An orthograde body plan , on the other hand, involves an animal moving with its body perpendicular to the ground, with limbs extending vertically underneath. This body plan is often seen in primates like humans and apes, allowing for more efficient bipedal locomotion.
- in forelimb-dominated, below-branch suspension, the body is this
Below-branch suspension vs. over-branch quadrupedalism
Below-branch suspension involves hanging from branches using the arms, while over-branch quadrupedalism involves moving along branches using all four limbs. Both forms of locomotion are adaptations to life in the trees, with below-branch suspension allowing for greater stability and over-branch quadrupedalism providing more speed and agility
Why do apes tend to move around the trees by climbing or hanging below branches, whereas monkeys walk around on all fours above branches?
Apes are larger bodied and have longer arms than monkeys, which allows them to swing and hang from branches more easily without breaking the branches. Monkeys, on the other hand, have shorter arms and smaller bodies, making it more efficient for them to walk on all fours across branches
Example of an adaptation that helps apes move around by swinging below branches
- long arms relative to legs
- short, stiff back
- very mobile wrist
- wide shallow crest with shoulder blades on back
- long, curved fingers
Identify the Y-5 pattern vs. bilophodont patterns in lower molars
The Y-5 pattern is characterized by five main cusps arranged in a Y-shape, while bilophodont patterns have two main transverse ridges
Y-5 pattern is on lower molars on: “bifurcation is buccal”
In monkeys, mesial and distal cusp pairs are separated (bilophodonty)
Ecology
The study of how an organism’s biology relates to the environment– especially extracting resources from the environment
Niche
The ecological “space” an organism takes up
Generalist/specialist
Generalists are species that can thrive in a wide range of environmental conditions and feed on a variety of resources, while specialists are adapted to specific habitats and diets.
Generalist=broad
Specialist=very narrow
Frugivory/folivory
Frugivory
- fruits
Folivory
- leaves
Arboreal terrestrial
Arboreal
- live primarily in trees
Terrestrial
- live primarily on the ground
Cooperative breeding
Allomaternal care
- care of offspring by nonparents
Paternity is certain so there is less male-male competition (one breeding male and female)
Which primates are cooperative breeders?
Humans, marmosets, and tamarins
How does cooperative breeding affect the number of offspring that can be produced?
Increases net reproductive output
- can have more and more closely spaced offspring, despite longer periods of dependence because not only ones using energy to care for young
Principle of competitive exclusion
Principle of competitive exclusion states that two species competing for the same limited resource cannot coexist in the same ecological niche for an extended period of time. This leads to one species outcompeting the other, resulting in either the extinction of one species or a shift in their ecological roles
Example of niche partitioning in primates
- change physical space occupying
- change diet
- Nocturnal vs. diurnal (temporal change)
Ex. different species of monkeys will occupy different levels of the forest canopy, with some species specializing in the upper canopy while others stick to the lower levels. This allows each species to access different food sources and avoid direct competition with one another. By utilizing different parts of the same habitat, these primates are able to coexist and thrive in the same environment without overlapping too much in their resource use
Describe an example of a primate adaptation that allows that group/species to occupy a specific dietary niche
- physiological and soft-tissue anatomy changes
- behavioral changes
- skeletal changes
One example of a primate adaptation for occupying a specific dietary niche is the specialized dental morphology of leaf-eating primates like colobus monkeys, which have sharp ridges on their molar teeth to efficiently process tough, fibrous leaves. This adaptation allows them to extract maximum nutrients from their primary food source and thrive in their forest habitats
Describe how canine size, canine dimorphism, and the canine-P3 honing complex relate to social structures in living primates
Canine size in primates is often correlated with social behavior, with larger canines typically seen in species where males compete for dominance and access to females. Canine dimorphism, or differences in canine size between males and females, can also reflect social hierarchies and mating strategies within primate groups. For example, in baboon societies, males with larger canines are often seen as more dominant and have greater access to mating opportunities. Additionally, the presence of a canine-P3 honing complex, which sharpens the canine teeth through repeated contact with the lower third premolar, can indicate aggressive behaviors and social interactions within primate societies. This honing complex is more commonly found in species where males use their canines for display and intimidation, such as in gorillas and some species of monkeys. Overall, canine dimorphism and the presence of a honing complex can provide valuable insights into the social dynamics and reproductive strategies of primates
Explain how fossilization occurs from burial to discovery
1.) Burial under specific conditions
- quickly covered is good
- certain kinds of sediments are better than others
2.) Mineral replacement
- biological minerals are replaced by rock minerals (diagenesis)
3.) Exposure
