Spanning Evolution: The Hominid Family Tree
Fossils for a large number of hominid species, including pre-human primates and human primates, have been found by paleontologists. As shown in this chart, various hominid species have been identified from fossil remains. Take a look these distant and not-so-distant relations:
| Species* | Where Found | Lived (mya= million years ago) | Interesting Characteristics |
| A. anamensis |
Kenya |
4.2 to 3.9 mya |
Probably walked upright |
| A. afarensis |
Ethiopia, Kenya |
3.6 to 2.9 mya |
Walked upright. Most famous member (to us anyway) is Lucy, the nearly complete fossil found in 1974 |
| A. africanus |
South Africa |
3 to 2 mya |
Teeth more human-like than ape-like, probably bipedal |
| A. aethiopicus |
Ethiopia |
2.7 to 2.3 mya |
Considered a transitional species between A. afarensis and A. boisei |
| A. garhi |
Ethiopia |
2.5 mya |
Possibly the earliest tool user |
| A. boisei |
Tanzania, Ethiopia |
2.3 to 1.4 mya |
Formerly considered to be a direct human ancestor until H. habilis was discovered |
| A. robustus |
South Africa |
1.8 to 1.5 mya |
May have used tools to dig up edible roots |
| H. rudolfensis |
Kenya, Tanzania |
2.4 to 1.8 mya |
Bipedal with a large brain |
| H. habilis |
Kenya |
2.3 to 1.6 mya |
"Handy man"; used tools, brain larger and more humanshaped, possibly capable of rudimentary speech |
| H. ergaster |
Eastern and South Africa |
1.9 to 1.4 mya |
Made some nice tools, had smaller teeth |
| H. erectus |
Republic of Georgia, Kenya, China, Indonesia and Europe |
1.9 to 0.3 mya (and possibly 50,000 years ago) |
Definitely used tools, probably discovered fire, andmay have lived at same time as modern humans |
| H. heielbergensis |
Africa, Europe |
600,000 to 100,000 years ago |
Brain size equal to modern humans, found with tools sharp enough to slice through animal hides, almost certainly used fire |
| H. neanderthalensis |
Europe,Middle East |
250,000 to 30,000 years ago |
Lived mostly in cold climates, shared the earth with H. sapiens, may have had a complex social system that care for the elderly and burial rituals |
| H. sapiens |
Worldwide |
100,000 years ago to today |
Large brains (not always used) and ability to manipulate tools, situations, and the emotions of other H. sapiens |
*Note: The A or H in the species' names is scientific shorthand. Instead of writing Australopithecus, for example, scientists simply write A. The term Australopithecus speaks to the origin of the fossil: southern Africa. H, of course, stands for Homo, which means man. Sapiens means wise, so the name Homo sapiens means wise man.

Biology Glossary
anemia
A low number of red blood cells or low level of hemoglobin; may be caused by dietary deficiencies, metabolic disorders, hereditary conditions, or damaged bone marrow.

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antigen
A foreign substance in the body that causes an immune response.

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body mass index
The BMI is the result of a formula that uses your weight and height to determine whether you need to lose weight.

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carbohydrates
Energy-packed compounds consisting of carbon, hydrogen, and oxygen that provide quick fuel for organisms.

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cellulose
A form of carbohydrate that has a structural role in living organisms (animals and plants).

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centrifuge
A machine that is used to separate blood cells and platelets from plasma.

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chloroplasts
Plant cells that use energy from sunlight to create food.

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cytoplasm
The fluid contained within animal cells. Also called plasma.

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disaccharides
Carbohydrate molecules in which 2 monosaccharide molecules are joined together. Disaccharides consist of 6 to 14 carbon atoms.

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DNA
Stands for deoxyribonucleic acid. Large molecules found in all living things that carry genetic information.

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electron microscope
A high-powered, expensive device that uses beams of electrons to bring the finest details of cells into focus.

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endocrine system
A system of glands that secrete different types of hormones that help regulate organisms.

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endoplasmic reticulum
The ER is a series of canals that connects the nucleus of animal cells to the cytoplasm outside those cells.

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equilibrium
The state of a chemical reaction in which the amounts on each side of the reaction have stabilized.

Biology Glossary
eukaryotes
Organisms — including plants and animals, as well as fungi, protozoa, and most algae — with cells that contain a nucleus and chromosomes.

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Golgi apparatus
A component within cells that packages and distributes hormones, enzymes, and other cell products to other organelles or outside the cell.

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hemoglobin
An iron-containing molecule in red blood cells that carries oxygen around the body.

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heterotrophs
Animals — including herbivores, carnivores, and omnivores — that feed on other living organisms.

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homeostasis
The processes used by the body to constantly achieve and maintain balance.

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integument
The skin or outer surface of an animal. Small animals such as earthworms use integumentary exchange to exchange gases with the environment.

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Krebs cycle
A method of describing the steps involved in the chemical process of respiration.

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lipoproteins
Compounds such as HDL and LDL that carry cholesterol through the bloodstream; made from a fat (lipid) and a protein.

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lysosomes
Specialized cellular organelles formed by the Golgi apparatus that help to clean up the cell by breaking down harmful cell products and removing dead organelles.

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maceration
A process, such as chewing, that physically breaks down food into pieces.

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matrix
The extracellular fluid in which animal cells float.

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mitochondria
An organelle in animal cells that combines food with oxygen to supply energy to cells.

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monosaccharides
Carbohydrate molecules in which simple sugars consist of three to seven carbon atoms.

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nuclear membrane
A two-layer structure that separates the nucleus from the cytoplasm in animal cells.

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organelles
Structures that float inside the fluid of cells; used during metabolic processes.

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osmosis
A mechanism that moves water and nutrients into and throughout a plant.

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peristalsis
The action of food being moved down the esophagus and through the entire digestive tract.

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peroxisomes
Sacs of enzymes within animal cells that help protect the cell by breaking down accumulations of toxic products such as hydrogen peroxide.

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photosynthesis
The biochemical process that plants use to acquire energy from the sun.

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plasma membrane
The membrane that holds fluid within animal cells. Also called the cell membrane.

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polysaccharides
Carbohydrate molecules that are formed by many long chains of monosaccharides.

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prokaryotes
Organisms — such as bacteria and blue-green algae — with cells that do not contain a nucleus.

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ribosomes
Components within cells that assist in making proteins from amino acids.

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RNA
Stands for ribonucleic acid. In animals, works with DNA to produce proteins needed throughout the body.

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ruminants
Mammals — such as cattle, sheep, and goats — that can break down and digest cellulose.