Lecture 23-24: Amniotes and Primates

Vocabulary flashcards covering key terms and concepts from the lecture notes.

Ancestral Deuterostome

The common ancestor to both echinodermata and chordates

Notochord

A flexible rod that supports the body in chordates.

Vertebrae

Bones or cartilage that surround the spinal cord and support the body.

Gnathostomes

Vertebrates with jaws and a mineralized skeleton.

Osteichthyans

Vertebrates with lungs or lung derivatives.

Lobe-fins

Fleshy fins supported by bones.

Tetrapods

Vertebrates with limbs with digits.

Amniotes

Tetrapods with an amniotic egg.

Milk

A nutritious fluid produced by mammals to feed their young.

Amniotic Egg

Major derived character of amniotes, contains specialized membranes.

Allantois

A disposal sac for certain metabolic wastes produced by the embryo within the amniotic egg.

Amnion

Protects the embryo in a fluid-filled cavity that cushions against mechanical shock.

Chorion

Exchanges gases between the embryo and the air along with the membrane of the allantois within the amniotic egg

Yolk sac

Contains the yolk, a stockpile of nutrients.

Albumen

Additional nutrients stored in the egg white.

Reptiles

A clade of amniotes that includes non-bird reptiles and birds.

Mammals

A clade of amniotes characterized by mammary glands, hair, and differentiated teeth.

Monotremes

Egg-laying mammals.

Marsupials

Mammals with a pouch.

Eutherians

Placental mammals.

Placenta

Structure in which nutrients diffuse into the embryo from the mother's blood.

Primates

Mammalian order including lemurs, tarsiers, monkeys, and apes characterized by hands and feet adapted for grasping.

Anthropoids

A group of primates including monkeys and apes.

Apes

A group of primates including gibbons, orangutans, gorillas, chimpanzees, bonobos, and humans.

Bipedality

The ability to walk upright on two legs.

Hominin

A species that is more closely related to humans than to chimpanzees.

Culture

A system of shared meanings, symbols, customs, beliefs, and practices that are learned by teaching or by imitation.

Homo habilis

An early species of the genus Homo known for its association with stone tools. Smaller size and less developed skeletal features.

Homo erectus

An extinct species of hominin that was the first to migrate out of Africa.

Homo sapiens

The species of modern humans.

Ardipithecus ramidus

An early hominin species that provides insights into the evolution of bipedality and the common ancestor of humans and chimpanzees.

Sahelanthropus tchadensis

One of the oldest known hominin species.

Orrorin tugenensis

An early hominin species found in Kenya.

Australopithecus afarensis

An early hominin species known from the 'Lucy' fossil.

Australopithecus africanus

A species of australopithecine that lived in South Africa.

Paranthropus boisei

A robust australopithecine known for its large teeth and jaws.

Paranthropus robustus

A species of Paranthropus that lived in South Africa.

Kenyanthropus platyops

A hominin fossil discovered in Kenya.

Homo neanderthalensis

A species of archaic humans that lived in Europe and western Asia.

Oldowan

The oldest-known stone tool industry.

Acheulean

A stone tool industry associated with Homo erectus and early Homo sapiens.

Chordates

Animals that at some point during their development have a notochord; a flexible, rod-shaped structure that supports the body.

Vertebrates

Chordates that have a backbone or spinal column.

Lobed Fins

Fins with skeletal support that resemble limbs, allowing for movement in shallow water and on land.

Myxini

Hagfishes; jawless vertebrates with a skull.

Petromyzontida

Lampreys; jawless vertebrates with a vertebral column of cartilage.

Chondrichthyes

Sharks, rays, and chimaeras; vertebrates with a skeleton made of cartilage.

Actinopterygii

Ray-finned fishes; vertebrates with bony skeletons and fins supported by rays.

Actinistia

Coelacanths; lobe-finned fishes thought to be extinct until rediscovered.

Dipnoi

Lungfishes; lobe-finned fishes with lungs for breathing air.

Amphibia

Amphibians; vertebrates that live both in water and on land.

Reptilia

Reptiles; vertebrates with scales and amniotic eggs.

Mammalia

Mammals; vertebrates with hair, mammary glands, and differentiated teeth.

Echinodermata

Phylum of marine animals closely related to chordates (e.g., starfish and sea urchins).

Cephalochordata

Subphylum of chordates that includes lancelets; small, fish-like filter feeders.

Urochordata

Subphylum of chordates that includes tunicates or sea squirts; marine filter feeders with a notochord in the larval stage.

Amniotic Cavity

A fluid-filled space within the amniotic egg that cushions the embryo.

Homologous Structure

Structures in different species that have a common evolutionary origin.

Derived Characteristic

A trait that appears in the most recent common ancestor of a group of organisms and is not found earlier in the phylogeny.

Convergent Evolution

The independent evolution of similar features in different lineages.

Out of Africa Hypothesis

The theory that Homo sapiens evolved in Africa and then migrated to other parts of the world, replacing other hominin species.

Grasping Hands and Feet

A derived characteristic of primates that allows for climbing and manipulating objects.

Opposable Thumb

A thumb that can be moved opposite the fingers, allowing for grasping and fine motor skills.

Flat Nails

A derived characteristic of primates that replaces claws and allows for more sensitive manipulation.

Parental Care

Care provided by parents to their offspring, which increases the offspring's chances of survival.

Social Behavior

The interactions among individuals of the same species, which can include cooperation, competition, and communication.

Bipedality

The ability to walk upright on two legs; a derived characteristic of hominins.

Symbolic Thought

The ability to use symbols to represent objects, ideas, and events; a cognitive ability associated with humans.

Archaic Homo Sapiens

An extinct subspecies of humans that lived in Africa, Asia, and Europe during the Middle Pleistocene (~781,000 to 126,000 years ago.

Differentiated Teeth (Heterodonty)

Possessing a variety of teeth with sizes and shapes adapted for eating many kinds of food