BIOL100 Ch. 17: Animals and Human Evolution

Animals

Multicellular ingestive heterotrophs; that is, complex organisms (eukaryotes) that obtain energy and carbon by ingesting food into their bodies and digesting it internally

Chordates

A large phylum that encompasses all animals with backbones. such as fishes, birds, and mammals (dorsal nerve cord)

Vertebrates

Animals that have a backbone

Invertebrates

Animals without backbones

Radial symmetry

An animal body plan in which the body can be sliced symmetrically along any number of planes and pass through the animal, such as cnidarians

Bilateral symmetry

An animal body plan in which the body can be divided by just one plane passing vertically from the top to bottom of the animal into two halves that mirror each other.

Notochord

In chordates, a flexible yet rigid rod along the length of the body is critical for development

Nerve cord

A solid strand of nervous tissue that we call the spinal cord in humans.

Cartilage

A dense tissue of the skeleton that combines strength with flexibility. It is found almost everywhere that two bones meet and prevents them from grinding together

Segments

Repeated identical units that make up the body plan of arthropods, annelids, and vertebrates

Appendages

Body parts with specialized functions that develop in pairs from particular segments of an animal's body

Mammals

A large class of animals that are defined by:

Body hair

Sweat Glands

Milk is produced by mammary glands

Eutherians

One of the 3 main groups of mammals, whose members have a placenta and produce offspring that are born in a relatively well-developed state. Humans are eutharians.

Marsupials

One of three main groups of mammals, whose members have a simple placenta and produce offspring that complete development in their mothers couch, such as a kangaroo or koala

Monotremes

One of three main groups of mammals, whose members lack a placenta and lay eggs, such as platypi

Primates

The order of mammals to which humans belong. All primates have flexible shoulder and elbow joints, five functional fingers and toes, opposable thumbs, flat nails, and large brains in relative size to their body

Opposable

Able to be placed opposite other digits of the hand or foot. For example, opposable thumbs can be placed opposite each other of the other four fingers

Bipedal

the ability to walk upright on two legs

Hominids

The ape family, which includes humans and chimpanzees. All hominids are capable of tool use, symbolic language, and deliberate acts of deception

Hominins

The "human" branch of hominids, including modern humans and extinct relatives such as Neanderthals

Australopiths

(3-3.5 mya) A colloquial name referring to a diverse group of Plio-Pleistocene African hominins. Australopiths are the most abundant and widely distributed of all early hominins and are also the most completely studied.

Homo lineage broke off from Australopithecus about 2 million years ago

Other lineages, such as Homohabilis, Homoerectos, Neanderthals, (Modern & archaic) Homosapiens began to separate (All members of the Homo genus).

Modern humans are a mix of these

Mitochondrial DNA inheritance

The passing down of DNA from the mitochondria in an egg cell to a new generation. mitochondrial DNA passes virtually unchanged from mother to child, so it can be tracked from one generation, or species, to another. Sequencing of mitochondrial DNA can determine how related an individual is to its female ancestors on its mother's side.

Nuclear DNA inheritance

The passing down of DNA from the nucleus in an egg or sperm cell to a new generation. Sequencing of nuclear DNA an determine how related an individual is to all of its ancestors, both male and female.