Biology And Human Evolution Human Biology and Evolution Humans are Alive The earliest human life form can be traced back more than 3.5 billion years ago. Humans are said to be descendants of a single celled ancestor. Although they are different in size and shape all basic functions are alike. The more complex the organization of the cell became the more successful and developed it became. As these single celled organisms developed they became known as pre-humans.
We share many characteristics with these pre-humans. Some of these characteristics include the masters of heredity DNA and RNA as well as proteins composed of amino acids, membranes or bound cells and lastly controlled cell division or mitosis, key to the daughter cells. Kingdoms are Alive The diversity of kingdoms is arranged into kingdoms that classify organisms from simple to complex. The traditional five kingdoms are Prokaryote, Protoctista, Fungi, Plantae, and Anamalia. Prokaryote is a bacterium that lacks nuclear membrane. Protoctista is a heterogeneous grouping that combines a great diversity of forms. Fungi are known for being important agents of composition they include yeast and mushroom. Plantae, are categorized as plants that use sunlight to convert to energy. Lastly Anamalia, Anamalial members are multicellular and fully mobile, they obtain their nutrients from other living things.
Our Place in Nature Humans are hierarchically classified into a series of increasingly specific groups. They range from the Kingdom Animalia to the Genus Homo, the Homo Sapiens appears to be its only living representative Kingdom: Animalia Phylum: Chordata Subphylum: Vertabrata Class: Mammalia Family: Hominidfae Genus: Homo Our Place in time Over a considerably large span of geological time life on earth has changed drastically. Humans and their close relatives are the most recent arrivals in the Tertiary period. The periods range Precambrian which was over 56 million years ago to Quaternary which was 1.8 million years ago to present. In this chart you will be able to see all periods ranging from Precambrian to Quaternary.
TABLE PERIOD AGE (MILLIONS OF YEARS) SOME IMPORTANT EVENTS IN THE HISTORY OF LIFE Quaternary 0.01 1.8 Historic time ice ages; humans appear Tertiary 5 65 Apelike ancestors of humans appear major radiation of mammals, birds, and pollinating insects Cretaceous 144 Flowering plants appear; dinosaurs and many groups of organisms become instinct at end of period Jurassic 208 Gymnosperms continue as dominant plants; dinosaurs dominant; first birds Triassic 245 Gymnosperms dominate landscapes; first dinosaurs and mammals Permian 286 Radiation of reptiles; origins of mammal-like reptiles and most modern orders of insects Carboniferous 360 Extensive forests of vascular plants; first seed plants; origin of reptiles; amphibians dominant Devonian 408 Diversification of bony fishes; first amphibians and insects Silurian 438 Diversity of jawless vertebrates; colonization of land by Plants and anthropods; origins of vascular plants Ordovician 505 First vertebrates (jawless fishes); Marine algae abundant Cambrian 544 Origin of most invertebrate phyla; Diverse algae Precambrian 700 4600 Origin of first animals Approximate origin of the earth Biosystems the Movie I viewed a video illustrating the senses through modern dance. The video was very graphic and detailed and showed a virtual tour of the organs. First I observed how deoxidized blood travel through the heart chambers to the lungs to get oxidized this was done through the cardiovascular system. Then I observed three parts of the nervous system, the ear, eye and the brain. I then took a tour through the urinary system, the digestive system, respiratory system and finally the musculoskeloton system, which concluded the film.
Humans are Vertebrates Humans are placed in the subphylum vertebrata. The category vertebrata contains all animals with a backbone. This group contains diverse animals such as fish, amphibians, reptiles, birds and mammals. Most of our familiar body systems are shared with vertebrates. Musculoskeletal System A skeleton family of four and a dog in a living room watching baseball illustrated the musculoskeletal system. The baseball game was actually an informational video on the joints and muscles of the upper body. Circulatory System The circulatory system has three main components, the lymphatic system, capillaries and blood. The lymphatic system transports intercellular fluid through the circulatory system.
Capillaries are microscopic blood vessels whose wall is only one cell in thickness. They carry blood opulent in oxygen and nutrients to all tissues in the body. Urinary System The kidney in the urinary system regulates the chemical composition of the blood thus also regulating the chemical composition of the body tissues. The functional unit of the kidney is known as a nephron and it absorbs much of the soluble nutrient molecules, certain mineral ions and some water. This mixture is also referred to as urine.
The urinary bladder then collects this urine from the ureter and stores it for periodic excretion from the body. Endocrine System The endocrine system consists of a number of discrete glands located on various points in the body. The endocrine glands lack ducts, therefore they communicate amongst each other chemically. The thyroid glands regulate metabolism. The pituitary glands control the endocrine glands and adrenal glands located on the kidneys separate into two regions, the cortex and the medulla.
The cortex controls water balance and blood pressure. The medulla increases the rate of metabolism, heartbeat, and breathing and simulates the conversion of glycogen into glucose. Nervous System Brains differ among species. Vertebrate brains vary enormously between one another in both absolute and relative size. They also differ largely in the sizes of various brain components relative to each other.
A number of different brain replicas ranging in body size from muskrat, which was about the size of a walnut to dolphin, which was about the relative size of a human brain. The Six Senses The site of communication when a chemical messenger from one cell stimulates activities of another is called synapsis. The components of synapsis are sight, hearing and balance, touch, taste and smell. These six senses enable us to function efficiently. Humans are Mammals There are many differences among mammals. Humans have milk mammary glands, hair, single bone structure in the lower jaw, three-bone middle ear structure, high fixed body temperature etc.
But the most significant difference is the male and female apparatus differ greatly among other animals of the same species. Some mammals may be classified as placental, monotiems and marsupial reproducers. Humans are Primates Our anatomical structure clearly reveals our common heritage with other primates: lemurs, louers, tarsiers, monkeys and apes. Early Primate Evolution Earliest primates date from around 65 million years ago, at the very beginning of the age of mammals. They do not resemble the primates of today.
Cookei, belonging to the genus Plesiadapis is 56 million years old she is the most complete skeleton of her time. Early Modern Primates 57 million years ago primates similar to present day lemurs became well established in forests and north continents. Northatcus Tenebrosus found in Wyoming and was 48 million years old. Humans are Higher Primates Together with the monkeys, apes etc. humans are informally categorized as higher primates. More technically humans belong to a suborder of primates called Anthropordeals Itoplornine.
Humans are Hominoids The closest living human relatives to the human species are the lesser apes (gibbons and siamangs) and the great apes (gorillas, chimpanzees and orangutan) We are all classified under subfamily Hominoidea. Yet it is with the great apes that we share the most extensive similarities and most common ancestry. An early orangutan relative found in Indonesia on the islands of Sumatra and Borneo. Proven to be the most clearly identifiable fossils relative of an orangutan. I observed them to be almost exactly alike.
Yet there were many missing pieces to the ancient skull that made it difficult to come to any definite conclusion. The parts that were found wee seemingly identical to that of an orangutan. Human Evolution Lucy One of the first known pre-humans was found in 1974 in Ethiopia. It was named Lucy after the popular Beatles song Lucy in the Sky with Diamonds. Lucy is 3.2 million years old, 3foot 6inches and 55 pounds. Turkana Boy Turkana boy was found in 1984 at Navio Kotome in North Kenya.
When found Turkana boy was 5foot 3inches and 106 pounds. If Turkana boy had lived scientists believed he would have grown to be 6foot 1inches and 150 lbs. Earliest Human Relatives As I previously stated one of the earliest human relatives was Lucy. Her scientific name is Australopithecus Afaransis. Lucy and others like Turkana Boy show evidence of walking upright.