ANTH TEST 2 STUDY UPDATED

Chapter 5: Primate Traits & Evolutionary Differences

Primitive vs. Derived Traits

• Primitive Traits: Ancestral characteristics shared across multiple species, such as the presence of five fingers in primates, indicating a common evolutionary lineage.

• Derived Traits: Unique evolutionary developments that arise in specific lineages, exemplified by bipedalism in humans, which distinguishes them from other primates.

Genetic Similarity and Vision

• Human & Chimp DNA Similarity: Humans share approximately 98-99% of their DNA with chimpanzees, highlighting close evolutionary relationships.

• Trichromatic Vision: This trait is present in Old World monkeys and apes, allowing them to distinguish between red, green, and blue, which is crucial for foraging and social interactions.

New World vs. Old World Primates

• New World Monkeys (Platyrrhines): Found in South America, characterized by prehensile tails and a dental formula of 2:1:3:3, which aids in their arboreal lifestyle.

• Old World Monkeys & Apes (Catarrhines): Located in Africa and Asia, these primates lack prehensile tails and have a dental formula of 2:1:2:3, reflecting their different ecological adaptations.

Dental Characteristics and General Traits

• Homodont vs. Heterodont: Homodont refers to species with teeth of the same shape (e.g., sharks), while heterodont describes species with different types of teeth, such as mammals, including primates, which have incisors, canines, and molars for varied diets.

• General Primate Characteristics: Primates typically exhibit grasping hands, forward-facing eyes for depth perception, larger brain sizes relative to body size, and complex social behaviors.

Primate Locomotion and Classification

• Types of Locomotion: Bipedalism (walking upright, unique to humans) and brachiation (arm swinging, seen in gibbons) are key locomotor adaptations in primates.

• Grade vs. Clade: A grade groups organisms based on physical characteristics (e.g., monkeys vs. apes), while a clade groups them based on shared evolutionary ancestry, emphasizing the importance of common descent.

Chapter 6: Primate Ecology & Behavior

Food Abundance & Distribution

• Frugivores: Primates that primarily eat fruits require large home ranges to find sufficient food resources.

• Folivores: Leaf-eating primates can remain in a smaller area due to the abundance of their food source, which is more stable than fruit availability.

• Insectivores: These primates need to be agile and fast-moving to catch their prey, influencing their habitat and social structures.

Community Ecology and Niche Dynamics

• Community Ecology: Examines how primates interact with their environment and other species, influencing their behavior and social structures.

• Niche & Competitive Exclusion Principle: Each species has a specific role in its ecosystem (niche), and the principle states that no two species can occupy the same niche indefinitely without competition leading to one species outcompeting the other.

Social Structures and Reproductive Strategies

• Predator Avoidance: Group living enhances survival through collective vigilance, utilizing alarm calls and mobbing behavior to deter predators.

• Reproductive Strategies: Female primates often prioritize food availability for raising offspring, while males focus on maximizing mating opportunities, leading to different social dynamics.

Social Bonding and Dominance Hierarchies

• Polygyny: A common mating system in primates where one male mates with multiple females, influencing social structures and competition among males.

• Social Bonding Activity: Grooming is a critical behavior that helps reduce tension and maintain social relationships within primate groups.

Chapter 7: Fossils & Dating Methods

Contributions of Key Figures

• Hutton & Lyell: Pioneers of the concept of uniformitarianism, which posits that Earth's geological processes are gradual and continuous over time, shaping the planet's features.

• Mary Anning: A significant figure in paleontology, known for her fossil discoveries that contributed to the understanding of prehistoric life and the development of evolutionary theory.

Fossilization Processes

• Fossil Formation: Occurs when organic material is replaced by minerals, requiring rapid burial and specific environmental conditions to preserve remains.

• Taphonomy: The study of how organisms decay and become fossilized, providing insights into past ecosystems and the conditions necessary for fossil preservation.

Geological Time and Dating Techniques

• Pangea: A supercontinent that existed approximately 200 million years ago, influencing the distribution and evolution of species.

• Steno’s Law: The Law of Superposition states that in undisturbed rock layers, the oldest layers are at the bottom, providing a relative dating framework for fossils.

Dating Techniques Overview

• Relative Dating: Techniques such as stratigraphy compare the ages of fossils based on their positions in sedimentary layers, providing a relative timeline.

• Absolute Dating: Methods like radiocarbon dating offer precise ages for fossils, allowing for a more accurate understanding of the timing of evolutionary events.

Chapter 8: Primate Evolution & Miocene Climate

Early Primate Ancestors

• Purgatorius: Considered an early primate ancestor, this small, tree-dwelling creature provides insights into the origins of primate traits and behaviors.

• South American Primates Origin: The rafting hypothesis suggests that New World monkeys originated from Africa, highlighting the role of geographic events in primate evolution.

Locomotion Differences

• New World Monkeys: Adapted for an arboreal lifestyle with prehensile tails that aid in grasping branches and navigating trees.

• Old World Monkeys & Apes: Exhibit both terrestrial and arboreal locomotion but lack prehensile tails, reflecting different evolutionary pressures and adaptations.

Miocene Climate and Primate Diversification

• Miocene Climate: Characterized by warm and tropical conditions, this era facilitated the diversification of primates, leading to the emergence of various lineages.

• Evolutionary Hypotheses: The visual predation hypothesis suggests that primates evolved traits for hunting insects in trees, while the arboreal hypothesis posits that adaptations arose for life in trees.

Notable Primate Species

• Omomyoids & Adapoids: Early primate groups, with omomyoids linked to tarsiers and adapoids to lemurs, illustrating the diversity of early primate evolution.

• Gigantopithecus: A giant ape known for its large size and teeth adapted for a fibrous diet, possibly including bamboo, indicating dietary specialization.

Chapter 5: Primate Traits and Characteristics

What is the difference between primitive and derived traits?

• Primitive Traits: Inherited from distant ancestors and shared with other species (e.g., five fingers in primates).

• Derived Traits: More recently evolved and unique to a specific group (e.g., bipedalism in humans).

Humans and Chimpanzees share how much of our DNA?

• 98-99% of our DNA is shared with chimpanzees.

What group of modern primates have trichromatic vision?

• Old World monkeys and apes (Catarrhines) have trichromatic vision, allowing them to see red, green, and blue.

What is the difference between New World and Old World primates?

• New World Primates (Platyrrhines):

  • Found in South America.

  • Have prehensile tails.

  • Dental formula: 2:1:3:3 (extra premolar).

• Old World Primates (Catarrhines):

  • Found in Africa and Asia.

  • No prehensile tails.

  • Dental formula: 2:1:2:3.

Primate Dental Characteristics

• Homodont: All teeth are the same (e.g., sharks).

• Heterodont: Different types of teeth (e.g., primates).

• Dental Formulas:

  • 2:1:3:3 (New World Monkeys)

  • 2:1:2:3 (Old World Monkeys, Apes, Humans)

Primates in general have what type of characteristic?

• Grasping hands and feet, forward-facing eyes, large brains, and flexible limb movement.

Larger canines in male primates are an indication of what?

• Sexual dimorphism and male competition for mates.

Primate Locomotion and Traits

• Bipedalism: Walking on two legs (humans).

• Brachiation: Swinging from branches using arms (gibbons).

• Quadrupedalism: Walking on all fours (monkeys).

• Knuckle-Walking: Walking on knuckles (chimpanzees, gorillas).

What is the difference between a grade and a clade?

• Grade: Grouped based on similar traits, even if not closely related.

• Clade: Grouped based on common ancestry.

Differences between Haplorhines, Strepsirrhines, and Catarrhines

• Haplorhines (Dry-Nosed Primates): Monkeys, apes, humans.

• Strepsirrhines (Wet-Nosed Primates): Lemurs, lorises.

• Catarrhines (Old World Monkeys & Apes): Include humans, lack prehensile tails.

What was our big adaptation?

• Bipedalism (walking on two legs), allowing for tool use and endurance running.

Chapter 6: Primate Ecology and Behavior

Food Abundance and Distribution

• Frugivores (fruit eaters): Typically have broad incisors.

• Folivores (leaf eaters): Have specialized molars for grinding.

• Insectivores (insect eaters): Have sharp cusped teeth.

Community Ecology

• Study of interactions between species in an environment.

What is a niche and what principle is important?

• Niche: The role a species plays in its environment.

• Competitive Exclusion Principle: No two species can occupy the same niche indefinitely.

Predator Avoidance

• Alarm calls, hiding, group living, and vigilance help primates avoid predators.

Obtaining food is a male or female reproductive strategy?

• Female reproductive strategy, as they need high-quality food for offspring.

What does polygynous mean?

• One male mates with multiple females.

What are hominoids?

• Apes and humans (no tails, large brains, complex behavior).

What is the competitive exclusion principle?

• Two species cannot occupy the same niche in an ecosystem for long.

Dominance hierarchies are uncommon among what type of primate food consumers?

• Folivores (leaf-eaters), since food is widely available.

What activity helps primates bond?

• Grooming, which strengthens social relationships.

Chapter 7: Fossils and Dating Techniques

Contributions of Hutton, Lyell, and Anning

• James Hutton: Introduced the concept of uniformitarianism (Earth shaped by gradual processes).

• Charles Lyell: Expanded uniformitarianism, showing Earth's changes over time.

• Mary Anning: Discovered important fossils, contributing to paleontology.

How old is the Earth?

• About 4.6 billion years old.

Fossils and Fossilization

• Fossils form when organisms are buried in sediment and mineralized.

What is Taphonomy?

• The study of how fossils are formed and preserved.

What was Pangea?

• A supercontinent that existed 300 million years ago.

What are trace fossils?

• Fossils that show evidence of activity (e.g., footprints, burrows).

• Example: Laetoli footprints—evidence of early bipedalism.

How are fossils made?

1. Organism dies.

2. Rapid burial in sediment.

3. Mineralization replaces organic material.

4. Fossil gets exposed through erosion.

Why is Steno important?

• Developed the Law of Superposition: Older rock layers are beneath younger ones.

What is Dendrochronology?

• Tree-ring dating, used to determine past environmental conditions.

Main Types of Dating Techniques

• Relative Dating: Compares fossils (e.g., stratigraphy).

• Absolute Dating: Determines exact age (e.g., radiocarbon dating).

Chapter 8: Primate Evolution

Why is Purgatorius important?

• One of the earliest primate ancestors.

Where did South American primates originally come from?

• Likely rafted from Africa on floating vegetation.

New World vs. Old World Primate Locomotion

• New World: Mostly arboreal, use prehensile tails.

• Old World: More ground-dwelling, no prehensile tails.

Climate of the Miocene

• Warmer and wetter, allowing primates to spread.

Visual Predation, Arboreal, and Angiosperm-Primate Coevolution Hypotheses

• Visual Predation Hypothesis: Evolved to hunt insects.

• Arboreal Hypothesis: Adapted to tree life.

• Angiosperm-Primate Coevolution Hypothesis: Evolved alongside flowering plants.

Omomyoids and Adapoids are considered to be what?

• Early primates:

  • Omomyoids: Likely led to tarsiers.

  • Adapoids: Likely led to lemurs.

Who was Gigantopithecus and what do the teeth tell us?

• Largest known primate; teeth suggest it ate tough plants like bamboo.

Where did Orangutans originate?

• Evolved from Miocene apes in Asia.

What type of environment do modern primates live in?

• Tropical forests, savannas, and some temperate regions.