Key Concepts in Evolution and Primatology

This set of flashcards covers key concepts in evolution and primatology, providing definitions and explanations to aid students in their studies.

traits inherited from a common ancestor?

Homologies

similar traits that evolve independently in different species?

Homoplasy

similar traits that lack a common ancestry called?

Analogies

features that come from ancestors referred to as?

Primitive Traits

features that have evolved over time?

Derived Traits

significant geological period lasted from 4.6 billion to 541 million years ago and marked the formation of Earth?

Pre-Cambrian.

era, from 541 to 252 million years ago, saw a rise in diverse life forms and included the Cambrian Explosion?

Paleozoic Era.

What era is known as the Age of Dinosaurs, lasting from 252 to 66 million years ago?

Mesozoic Era.

During which era did mammals begin to diversify after the extinction of dinosaurs?

Paleocene (66 - 56 million years ago).

What epoch saw rapid evolution of mammals and birds and development of modern flora?

Eocene (56 - 33.9 million years ago).

Which period (33.9 - 23 million years ago) featured the expansion of grasslands and early primates?

Oligocene.

What epoch, lasting from 23 to 5.3 million years ago, marked the emergence of early human ancestors?

Miocene.

Which epoch is known for significant evolution of hominins and modern species of mammals?

Pliocene (5.3 - 2.6 million years ago).

What period (2.6 million - 11,700 years ago) was characterized by ice ages and the emergence of anatomically modern humans?

Pleistocene.

What is the current epoch, marked by human civilization and environmental changes due to human activity?

Holocene (11,700 years ago - Present).

What geological processes, including plate tectonics, influenced evolutionary events?

Continental Drift.

How are fish characterized?

Aquatic vertebrates with gills, fins, and scales; lay eggs in water.

Describe amphibians.

Cold-blooded vertebrates that begin life in water with gills and later develop lungs; e.g., frogs and salamanders.

What defines reptiles?

Cold-blooded vertebrates with scaly skin that lay eggs on land; e.g., snakes, lizards.

How are birds characterized?

Warm-blooded vertebrates with feathers, beaks, and the ability to lay hard-shelled eggs; most can fly.

What defines mammals?

Warm-blooded vertebrates with hair or fur and mammary glands that produce milk.

What are monotremes?

Egg-laying mammals (e.g., platypuses, echidnas).

Describe marsupials.

Mammals that give birth to undeveloped young which typically grow in a pouch (e.g., kangaroos, koalas).

What are placentals (Eutherians)?

Mammals that give birth to fully developed young nourished in the womb via a placenta (e.g., humans, dogs).

Define specialized traits.

Features developed for specific functions that help survival in a particular environment.

What are unspecialized traits?

General features that can serve multiple functions, allowing flexibility in environments.

Describe gradual evolution.

Change happens slowly over long periods through small, steady changes.

What does punctuated equilibrium explain?

Species remain stable for long periods but undergo rapid changes during short significant events.

What is a postorbital bar?

A bony structure that partially encircles the eye socket, providing support and protection in some primates.

Define stereoscopic vision.

The ability to perceive depth and three-dimensional structure using both eyes.

What is a prehensile tail?

A tail capable of grasping or holding objects, aiding in balance or manipulation, typical in some primates.

What is the dental formula for New and Old World monkeys?

2-1-2-3 (2 incisors, 1 canine, 2 premolars, and 3 molars per quadrant).

What does the dental formula 2-1-2-3 indicate for hominoids?

Morphology of apes and humans; same arrangement as monkeys.

What is the dental formula of ancient Mesozoic mammals?

3-1-4-3 (3 incisors, 1 canine, 4 premolars, and 3 molars per quadrant).

Bipedalism, larger brain size, reduced canine teeth, tool use, complex language and social structure.

What are the main characteristics of hominins?

mosaic evolution

Different traits in a species evolve at different rates, leading to a complex evolutionary pattern.

What does a multidisciplinary approach in paleoanthropology involve?

Steps in searching, processing, analyzing, and interpreting hominin sites.

Where is Olduvai Gorge located, and why is it significant?

Tanzania; known as the "Cradle of Humankind" for early human fossils like Australopithecus.

Notable discovery was made at the Afar Triangle in Ethiopia?

"Lucy," a 3.2-million-year-old skeleton that provides insight into human bipedalism.

Why are the Omo and Turkana Regions significant?

They contain some of the oldest human fossils, such as Omo I and II (about 195,000 years old) and Turkana Boy.

What does relative dating establish?

The order of events, indicating whether one object is older or younger than another without giving exact dates.

What is absolute/chronometric dating?

A method that provides specific age estimates for objects or layers, often in years.

How does C-14 dating work?

Measures the decay of carbon-14 in organic materials, effective for dating up to about 50,000 years.

What is potassium-argon dating used for?

Dating volcanic rocks by measuring the ratio of potassium-40 to argon-40, effective for millions of years.

How does biostratigraphic dating work?

Uses fossil remains in rock layers to help date those layers based on known timelines of the fossils.

What are proto-primates?

Early ancestors of primates that lived during the Cretaceous period, displaying some features of modern primates.

What are true primates (Euprimates)?

Primates that appeared during the Eocene epoch, featuring larger brains and complex social behaviors.

What impact did the mass extinction event (Cretaceous-Paleogene) have on primates?

It allowed early primates to thrive by opening ecological niches after the dinosaurs' extinction.

What does parallel evolution refer to?

Two related species evolving similar traits independently due to similar environmental pressures.

What is convergent evolution?

Unrelated species evolving similar traits due to comparable environmental pressures.

Define divergent evolution.

Related species becoming more different over time due to different environments or lifestyles.

What defines continental drift in relation to ape evolution?

The movement of continents affected habitats, requiring primates to adapt and leading to different ape species evolving.

What challenges do scientists face in classifying early primates and hominoids?

Fragmentary fossils, similar features leading to classification confusion, and evolutionary overlap complicating timelines.

Who were notable researchers in primate studies?

Jane Goodall studied chimpanzees; Dian Fossey focused on mountain gorillas.

What are the distinctive characteristics that define primates?

Unique anatomical structures, social behaviors, and ecological adaptations.

What is the arboreal hypothesis?

Suggests primates evolved adaptations for life in trees, such as grasping hands and enhanced vision.

What does the visual predation hypothesis propose?

Primates evolved features for hunting small animals, like sharp eyesight and agile fingers.

Why are dental formulas significant?

They help classify primates and understand their diets based on the types and numbers of teeth.

What are the locomotion types found among various primate taxa?

Vertical clinging, knuckle walking, brachiation, and bipedalism.

evolutionary relationships exist between different primate groups

Strepsirhines (lemurs and lorises) vs. Haplorhines (tarsiers, monkeys, and apes).

What key features differentiate Old World and New World monkeys?

Old World Monkeys have narrow noses and usually tails; New World Monkeys have wider noses and many have prehensile tails.

What makes tarsiers difficult to classify within primates?

They share traits with both strepsirhines and haplorhines, complicating their exact taxonomy.

How do molecular data contribute to evolutionary studies?

Genetic data help clarify relationships and lineage among primate species.

What is adaptive radiation?

A process where a single species rapidly evolves into many forms to adapt to various environments.

What is cladistics?

A method of classifying organisms based on shared evolutionary history, creating a branching diagram.

What is mosaic evolution?

The concept that different traits in a species can evolve at different rates.

What is taxonomy?

The science of naming, describing, and classifying organisms into groups based on shared characteristics.

What is chronometric dating?

A method for determining the age of an object or fossil in years.

What does paleoanthropology study?

Ancient human ancestors and their evolutionary history through fossils.

What is biostratigraphic dating?

A method that uses certain fossils in rock layers to determine their relative age.

What do dental formulas represent?

The types and numbers of teeth in an animal's mouth, aiding in classification and diet understanding.

What defines hominins?

The group that includes modern humans and immediate ancestors, characterized by bipedalism and advanced cognition.