Aristotle's biology

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Aristotle's biology is the theory of biology, grounded in systematic observation and collection of data, mainly zoological, embodied in Aristotle's books on the science. Aristotle's biology_sentence_0

Many of his observations were made during his stay on the island of Lesbos, including especially his descriptions of the marine biology of the Pyrrha lagoon, now the Gulf of Kalloni. Aristotle's biology_sentence_1

His theory is based on his concept of form, which derives from but is markedly unlike Plato's theory of Forms. Aristotle's biology_sentence_2

The theory describes five major biological processes, namely metabolism, temperature regulation, information processing, embryogenesis, and inheritance. Aristotle's biology_sentence_3

Each was defined in some detail, in some cases sufficient to enable modern biologists to create mathematical models of the mechanisms described. Aristotle's biology_sentence_4

Aristotle's method, too, resembled the style of science used by modern biologists when exploring a new area, with systematic data collection, discovery of patterns, and inference of possible causal explanations from these. Aristotle's biology_sentence_5

He did not perform experiments in the modern sense, but made observations of living animals and carried out dissections. Aristotle's biology_sentence_6

He names some 500 species of bird, mammal, and fish; and he distinguishes dozens of insects and other invertebrates. Aristotle's biology_sentence_7

He describes the internal anatomy of over a hundred animals, and dissected around 35 of these. Aristotle's biology_sentence_8

Aristotle's writings on biology, the first in the history of science, are scattered across several books, forming about a quarter of his writings that have survived. Aristotle's biology_sentence_9

The main biology texts were the History of Animals, Generation of Animals, Movement of Animals, Progression of Animals, Parts of Animals, and On the Soul, as well as the lost drawings of The Anatomies which accompanied the History. Aristotle's biology_sentence_10

Apart from his pupil, Theophrastus, who wrote a matching Enquiry into Plants, no research of comparable scope was carried out in ancient Greece, though Hellenistic medicine in Egypt continued Aristotle's inquiry into the mechanisms of the human body. Aristotle's biology_sentence_11

Aristotle's biology was influential in the medieval Islamic world. Aristotle's biology_sentence_12

Translation of Arabic versions and commentaries into Latin brought knowledge of Aristotle back into Western Europe, but the only biological work widely taught in medieval universities was On the Soul. Aristotle's biology_sentence_13

The association of his work with medieval scholasticism, as well as errors in his theories, caused Early Modern scientists such as Galileo and William Harvey to reject Aristotle. Aristotle's biology_sentence_14

Criticism of his errors and secondhand reports continued for centuries. Aristotle's biology_sentence_15

He has found better acceptance among zoologists, and some of his long-derided observations in marine biology have been found in modern times to be true. Aristotle's biology_sentence_16

Context Aristotle's biology_section_0

Aristotle's background Aristotle's biology_section_1

Aristotle (384–322 BC) studied at Plato's Academy in Athens, remaining there for about 20 years. Aristotle's biology_sentence_17

Like Plato, he sought universals in his philosophy, but unlike Plato he backed up his views with detailed and systematic observation, notably of the natural history of the island of Lesbos, where he spent about two years, and the marine life in the seas around it, especially of the Pyrrha lagoon in the island's centre. Aristotle's biology_sentence_18

This study made him the earliest scientist whose written work survives. Aristotle's biology_sentence_19

No similarly detailed work on zoology was attempted until the sixteenth century; accordingly Aristotle remained highly influential for some two thousand years. Aristotle's biology_sentence_20

He returned to Athens and founded his own school, the Lycaeum, where he taught for the last dozen years of his life. Aristotle's biology_sentence_21

His writings on zoology form about a quarter of his surviving work. Aristotle's biology_sentence_22

Aristotle's pupil Theophrastus later wrote a similar book on botany, Enquiry into Plants. Aristotle's biology_sentence_23

Aristotelian forms Aristotle's biology_section_2

Main article: Hylomorphism Aristotle's biology_sentence_24

Aristotle's biology is constructed on the basis of his theory of form, which is derived from Plato's theory of Forms, but significantly different from it. Aristotle's biology_sentence_25

Plato's Forms were eternal and fixed, being "blueprints in the mind of God". Aristotle's biology_sentence_26

Real things in the world could, in Plato's view, at best be approximations to these perfect Forms. Aristotle's biology_sentence_27

Aristotle heard Plato's view and developed it into a set of three biological concepts. Aristotle's biology_sentence_28

He uses the same Greek word, εἶδος (eidos), to mean first of all the set of visible features that uniquely characterised a kind of animal. Aristotle's biology_sentence_29

Aristotle used the word γένος (génos) to mean a kind. Aristotle's biology_sentence_30

For example, the kind of animal called a bird has feathers, a beak, wings, a hard-shelled egg, and warm blood. Aristotle's biology_sentence_31

Aristotle further noted that there are many bird forms within the bird kind – cranes, eagles, crows, bustards, sparrows, and so on, just as there are many forms of fishes within the fish kind. Aristotle's biology_sentence_32

He sometimes called these atoma eidē, indivisible forms. Aristotle's biology_sentence_33

Human is one of these indivisible forms: Socrates and the rest of us are all different individually, but we all have human form. Aristotle's biology_sentence_34

Finally, Aristotle observed that the child does not take just any form, but is given it by the parents' seeds, which combine. Aristotle's biology_sentence_35

These seeds thus contain form, or in modern terms information. Aristotle's biology_sentence_36

Aristotle makes clear that he sometimes intends this third sense by giving the analogy of a woodcarving. Aristotle's biology_sentence_37

It takes its form from wood (its material cause); the tools and carving technique used to make it (its efficient cause); and the design laid out for it (its eidos or embedded information). Aristotle's biology_sentence_38

Aristotle further emphasises the informational nature of form by arguing that a body is compounded of elements like earth and fire, just as a word is compounded of letters in a specific order. Aristotle's biology_sentence_39

System Aristotle's biology_section_3

Soul as system Aristotle's biology_section_4

Main articles: Soul § Aristotle, and On the Soul Aristotle's biology_sentence_40

As analysed by the evolutionary biologist Armand Leroi, Aristotle's biology included five major interlocking processes: Aristotle's biology_sentence_41

Aristotle's biology_ordered_list_0

  1. a metabolic process, whereby animals take in matter, change its qualities, and distribute these to use to grow, live, and reproduceAristotle's biology_item_0_0
  2. a cycle of temperature regulation, whereby animals maintain a steady state, but which progressively fails in old ageAristotle's biology_item_0_1
  3. an information processing model whereby animals receive sensory information, alter it in the seat of sensation, and use it to drive movements of the limbs. He thus separated sensation from thought, unlike all previous philosophers except Alcmaeon.Aristotle's biology_item_0_2
  4. the process of inheritance.Aristotle's biology_item_0_3
  5. the processes of embryonic development and of spontaneous generationAristotle's biology_item_0_4

The five processes formed what Aristotle called the soul: it was not something extra, but the system consisting exactly of these mechanisms. Aristotle's biology_sentence_42

The Aristotelian soul died with the animal and was thus purely biological. Aristotle's biology_sentence_43

Different types of organism possessed different types of soul. Aristotle's biology_sentence_44

Plants had a vegetative soul, responsible for reproduction and growth. Aristotle's biology_sentence_45

Animals had both a vegetative and a sensitive soul, responsible for mobility and sensation. Aristotle's biology_sentence_46

Humans, uniquely, had a vegetative, a sensitive, and a rational soul, capable of thought and reflection. Aristotle's biology_sentence_47

Processes Aristotle's biology_section_5

Metabolism Aristotle's biology_section_6

Aristotle's account of metabolism sought to explain how food was processed by the body to provide both heat and the materials for the body's construction and maintenance. Aristotle's biology_sentence_48

The metabolic system for live-bearing tetrapods described in the Parts of Animals can be modelled as an open system, a branching tree of flows of material through the body. Aristotle's biology_sentence_49

The system worked as follows. Aristotle's biology_sentence_50

The incoming material, food, enters the body and is concocted into blood; waste is excreted as urine, bile, and faeces, and the element fire is released as heat. Aristotle's biology_sentence_51

Blood is made into flesh, the rest forming other earthy tissues such as bones, teeth, cartilages and sinews. Aristotle's biology_sentence_52

Leftover blood is made into fat, whether soft suet or hard lard. Aristotle's biology_sentence_53

Some fat from all around the body is made into semen. Aristotle's biology_sentence_54

All the tissues are in Aristotle's view completely uniform parts with no internal structure of any kind; a cartilage for example was the same all the way through, not subdivided into atoms as Democritus (c. 460–c. Aristotle's biology_sentence_55

370 BC) had argued. Aristotle's biology_sentence_56

The uniform parts can be arranged on a scale of Aristotelian qualities, from the coldest and driest, such as hair, to the hottest and wettest, such as milk. Aristotle's biology_sentence_57

At each stage of metabolism, residual materials are excreted as faeces, urine, and bile. Aristotle's biology_sentence_58

Temperature regulation Aristotle's biology_section_7

Aristotle's account of temperature regulation sought to explain how an animal maintained a steady temperature and the continued oscillation of the thorax needed for breathing. Aristotle's biology_sentence_59

The system of regulation of temperature and breathing described in Youth and Old Age, Life and Death 26 is sufficiently detailed to permit modelling as a negative feedback control system (one that maintains a desired property by opposing disturbances to it), with a few assumptions such as a desired temperature to compare the actual temperature against. Aristotle's biology_sentence_60

The system worked as follows. Aristotle's biology_sentence_61

Heat is constantly lost from the body. Aristotle's biology_sentence_62

Food products reach the heart and are processed into new blood, releasing fire during metabolism, which raises the blood temperature too high. Aristotle's biology_sentence_63

That raises the heart temperature, causing lung volume to increase, in turn raising the airflow at the mouth. Aristotle's biology_sentence_64

The cool air brought in through the mouth reduces the heart temperature, so the lung volume accordingly decreases, restoring the temperature to normal. Aristotle's biology_sentence_65

The mechanism only works if the air is cooler than the reference temperature. Aristotle's biology_sentence_66

If the air is hotter than that, the system becomes a positive feedback cycle, the body's fire is put out, and death follows. Aristotle's biology_sentence_67

The system as described damps out fluctuations in temperature. Aristotle's biology_sentence_68

Aristotle however predicted that his system would cause lung oscillation (breathing), which is possible given extra assumptions such as of delays or non-linear responses. Aristotle's biology_sentence_69

Information processing Aristotle's biology_section_8

Aristotle's information processing model has been named the "centralized incoming and outgoing motions model". Aristotle's biology_sentence_70

It sought to explain how changes in the world led to appropriate behaviour in the animal. Aristotle's biology_sentence_71

The system worked as follows. Aristotle's biology_sentence_72

The animal's sense organ is altered when it detects an object. Aristotle's biology_sentence_73

This causes a perceptual change in the animal's seat of sensation, which Aristotle believed was the heart, not the brain. Aristotle's biology_sentence_74

This in turn causes a change in the heart's heat, which causes a quantitative change sufficient to make the heart transmit a mechanical impulse to a limb, which moves, moving the animal's body. Aristotle's biology_sentence_75

The alteration in the heat of the heart also causes a change in the consistency of the joints, which helps the limb to move. Aristotle's biology_sentence_76

There is thus a causal chain which transmits information from a sense organ to an organ capable of making decisions, and onwards to a motor organ. Aristotle's biology_sentence_77

In this respect, the model is analogous to a modern understanding of information processing such as in sensory-motor coupling. Aristotle's biology_sentence_78

Inheritance Aristotle's biology_section_9

See also: Telegony (pregnancy) Aristotle's biology_sentence_79

Aristotle's inheritance model sought to explain how the parents' characteristics are transmitted to the child, subject to influence from the environment. Aristotle's biology_sentence_80

The system worked as follows. Aristotle's biology_sentence_81

The father's semen and the mother's menses have movements that encode their parental characteristics. Aristotle's biology_sentence_82

The model is partly asymmetric, as only the father's movements define the form or eidos of the species, while the movements of both the father's and the mother's uniform parts define features other than the form, such as the father's eye colour or the mother's nose shape. Aristotle's biology_sentence_83

Aristotle's theory has some symmetry, as semen movements carry maleness while the menses carry femaleness. Aristotle's biology_sentence_84

If the semen is hot enough to overpower the cold menses, the child will be a boy; but if it is too cold to do this, the child will be a girl. Aristotle's biology_sentence_85

Inheritance is thus particulate (definitely one trait or another), as in Mendelian genetics, unlike the Hippocratic model which was continuous and blending. Aristotle's biology_sentence_86

The child's sex can be influenced by factors that affect temperature, including the weather, the wind direction, diet, and the father's age. Aristotle's biology_sentence_87

Features other than sex also depend on whether the semen overpowers the menses, so if a man has strong semen, he will have sons who resemble him, while if the semen is weak, he will have daughters who resemble their mother. Aristotle's biology_sentence_88

Embryogenesis Aristotle's biology_section_10

Aristotle's model of embryogenesis sought to explain how the inherited parental characteristics cause the formation and development of an embryo. Aristotle's biology_sentence_89

The system worked as follows. Aristotle's biology_sentence_90

First, the father's semen curdles the mother's menses, which Aristotle compares with how rennet (an enzyme from a cow's stomach) curdles milk in cheesemaking. Aristotle's biology_sentence_91

This forms the embryo; it is then developed by the action of the pneuma (literally, breath or spirit) in the semen. Aristotle's biology_sentence_92

The pneuma first makes the heart appear; this is vital, as the heart nourishes all other organs. Aristotle's biology_sentence_93

Aristotle observed that the heart is the first organ seen to be active (beating) in a hen's egg. Aristotle's biology_sentence_94

The pneuma then makes the other organs develop. Aristotle's biology_sentence_95

Method Aristotle's biology_section_11

Further information: History of scientific method Aristotle's biology_sentence_96

Aristotle has been called unscientific by philosophers from Francis Bacon onwards for at least two reasons: his scientific style, and his use of explanation. Aristotle's biology_sentence_97

His explanations are in turn made cryptic by his complicated system of causes. Aristotle's biology_sentence_98

However, these charges need to be considered in the light of what was known in his own time. Aristotle's biology_sentence_99

His systematic gathering of data, too, is obscured by the lack of modern methods of presentation, such as tables of data: for example, the whole of History of Animals Book VI is taken up with a list of observations of the life histories of birds that "would now be summarized in a single table in Nature – and in the Online Supplementary Information at that". Aristotle's biology_sentence_100

Scientific style Aristotle's biology_section_12

Aristotle did not do experiments in the modern sense. Aristotle's biology_sentence_101

He used the ancient Greek term pepeiramenoi to mean observations, or at most investigative procedures, such as (in Generation of Animals) finding a fertilised hen's egg of a suitable stage and opening it so as to be able to see the embryo's heart inside. Aristotle's biology_sentence_102

Instead, he practised a different style of science: systematically gathering data, discovering patterns common to whole groups of animals, and inferring possible causal explanations from these. Aristotle's biology_sentence_103

This style is common in modern biology when large amounts of data become available in a new field, such as genomics. Aristotle's biology_sentence_104

It does not result in the same certainty as experimental science, but it sets out testable hypotheses and constructs a narrative explanation of what is observed. Aristotle's biology_sentence_105

In this sense, Aristotle's biology is scientific. Aristotle's biology_sentence_106

From the data he collected and documented, Aristotle inferred quite a number of rules relating the life-history features of the live-bearing tetrapods (terrestrial placental mammals) that he studied. Aristotle's biology_sentence_107

Among these correct predictions are the following. Aristotle's biology_sentence_108

Brood size decreases with (adult) body mass, so that an elephant has fewer young (usually just one) per brood than a mouse. Aristotle's biology_sentence_109

Lifespan increases with gestation period, and also with body mass, so that elephants live longer than mice, have a longer period of gestation, and are heavier. Aristotle's biology_sentence_110

As a final example, fecundity decreases with lifespan, so long-lived kinds like elephants have fewer young in total than short-lived kinds like mice. Aristotle's biology_sentence_111

Mechanism and analogy Aristotle's biology_section_13

Aristotle's use of explanation has been considered "fundamentally unscientific". Aristotle's biology_sentence_112

The French playwright Molière's 1673 play The Imaginary Invalid portrays the quack Aristotelian doctor Argan blandly explaining that opium causes sleep by virtue of its , its virtus dormitiva. Aristotle's biology_sentence_113

Argan's explanation is at best empty (devoid of mechanism), at worst vitalist. Aristotle's biology_sentence_114

But the real Aristotle did provide biological mechanisms, in the form of the five processes of metabolism, temperature regulation, information processing, embryonic development, and inheritance that he developed. Aristotle's biology_sentence_115

Further, he provided mechanical, non-vitalist analogies for these theories, mentioning bellows, toy carts, the movement of water through porous pots, and even automatic puppets. Aristotle's biology_sentence_116

Complex causality Aristotle's biology_section_14

Main articles: Four causes and Tinbergen's four questions Aristotle's biology_sentence_117

Readers of Aristotle have found the four causes that he uses in his biological explanations opaque, something not helped by many centuries of confused exegesis. Aristotle's biology_sentence_118

For a biological system, these are however straightforward enough. Aristotle's biology_sentence_119

The material cause is simply what a system is constructed from. Aristotle's biology_sentence_120

The goal (final cause) and formal cause are what something is for, its function: to a modern biologist, such teleology describes adaptation under the pressure of natural selection. Aristotle's biology_sentence_121

The efficient cause is how a system moves and develops: to a modern biologist, those are explained by developmental biology and physiology. Aristotle's biology_sentence_122

Biologists continue to offer explanations of these same kinds. Aristotle's biology_sentence_123

Empirical research Aristotle's biology_section_15

Aristotle was the first person to study biology systematically. Aristotle's biology_sentence_124

He spent two years observing and describing the zoology of Lesbos and the surrounding seas, including in particular the Pyrrha lagoon in the centre of Lesbos. Aristotle's biology_sentence_125

His data are assembled from his own observations, statements given by people with specialised knowledge such as beekeepers and fishermen, and less accurate accounts provided by travellers from overseas. Aristotle's biology_sentence_126

His observations on catfish, electric fish (Torpedo) and angler fish are detailed, as is his writing on cephalopods including the octopus, cuttlefish and paper nautilus. Aristotle's biology_sentence_127

His claim that the octopus had a hectocotyl arm which was perhaps used in sexual reproduction was widely disbelieved, until its rediscovery in the 19th century. Aristotle's biology_sentence_128

He separated the aquatic mammals from fish, and knew that sharks and rays were part of the group he called Selachē (roughly, the modern zoologist's selachians). Aristotle's biology_sentence_129

Among many other things, he gave accurate descriptions of the four-chambered stomachs of ruminants, and of the ovoviviparous embryological development of the dogfish. Aristotle's biology_sentence_130

His accounts of about 35 animals are sufficiently detailed to convince biologists that he dissected those species, indeed vivisecting some; he mentions the internal anatomy of roughly 110 animals in total. Aristotle's biology_sentence_131

Classification Aristotle's biology_section_16

Aristotle distinguished about 500 species of birds, mammals and fishes in History of Animals and Parts of Animals. Aristotle's biology_sentence_132

His system of classification, one of the earliest in scientific taxonomy, was influential for over two thousand years. Aristotle's biology_sentence_133

Aristotle distinguished animals with blood, Enhaima (the modern zoologist's vertebrates) and animals without blood, Anhaima (invertebrates). Aristotle's biology_sentence_134

Aristotle's biology_table_general_0

Aristotle's Scala naturae (highest to lowest)Aristotle's biology_table_caption_0
GroupAristotle's biology_header_cell_0_0_0 Examples

(given by Aristotle)Aristotle's biology_header_cell_0_0_1

BloodAristotle's biology_header_cell_0_0_2 LegsAristotle's biology_header_cell_0_0_3 Soul

(Rational, Sensitive, Vegetative)Aristotle's biology_header_cell_0_0_4


(Hot–Cold, Wet–Dry)Aristotle's biology_header_cell_0_0_5

ManAristotle's biology_cell_0_1_0 ManAristotle's biology_cell_0_1_1 with bloodAristotle's biology_cell_0_1_2 2 legsAristotle's biology_cell_0_1_3 R, S, VAristotle's biology_cell_0_1_4 Hot, WetAristotle's biology_cell_0_1_5
Live-bearing tetrapodsAristotle's biology_cell_0_2_0 Cat, hareAristotle's biology_cell_0_2_1 with bloodAristotle's biology_cell_0_2_2 4 legsAristotle's biology_cell_0_2_3 S, VAristotle's biology_cell_0_2_4 Hot, WetAristotle's biology_cell_0_2_5
CetaceansAristotle's biology_cell_0_3_0 Dolphin, whaleAristotle's biology_cell_0_3_1 with bloodAristotle's biology_cell_0_3_2 noneAristotle's biology_cell_0_3_3 S, VAristotle's biology_cell_0_3_4 Hot, WetAristotle's biology_cell_0_3_5
BirdsAristotle's biology_cell_0_4_0 Bee-eater, nightjarAristotle's biology_cell_0_4_1 with bloodAristotle's biology_cell_0_4_2 2 legsAristotle's biology_cell_0_4_3 S, VAristotle's biology_cell_0_4_4 Hot, Wet, except Dry eggsAristotle's biology_cell_0_4_5
Egg-laying tetrapodsAristotle's biology_cell_0_5_0 Chameleon, crocodileAristotle's biology_cell_0_5_1 with bloodAristotle's biology_cell_0_5_2 4 legsAristotle's biology_cell_0_5_3 S, VAristotle's biology_cell_0_5_4 Cold, Wet except scales, eggsAristotle's biology_cell_0_5_5
SnakesAristotle's biology_cell_0_6_0 Water snake, Ottoman viperAristotle's biology_cell_0_6_1 with bloodAristotle's biology_cell_0_6_2 noneAristotle's biology_cell_0_6_3 S, VAristotle's biology_cell_0_6_4 Cold, Wet except scales, eggsAristotle's biology_cell_0_6_5
Egg-laying fishesAristotle's biology_cell_0_7_0 Sea bass, parrotfishAristotle's biology_cell_0_7_1 with bloodAristotle's biology_cell_0_7_2 noneAristotle's biology_cell_0_7_3 S, VAristotle's biology_cell_0_7_4 Cold, Wet, including eggsAristotle's biology_cell_0_7_5
(Among egg-laying fishes):

placental selachiansAristotle's biology_cell_0_8_0

Shark, skateAristotle's biology_cell_0_8_1 with bloodAristotle's biology_cell_0_8_2 noneAristotle's biology_cell_0_8_3 S, VAristotle's biology_cell_0_8_4 Cold, Wet, but placenta like tetrapodsAristotle's biology_cell_0_8_5
CrustaceansAristotle's biology_cell_0_9_0 Shrimp, crabAristotle's biology_cell_0_9_1 withoutAristotle's biology_cell_0_9_2 many legsAristotle's biology_cell_0_9_3 S, VAristotle's biology_cell_0_9_4 Cold, Wet except shellAristotle's biology_cell_0_9_5
CephalopodsAristotle's biology_cell_0_10_0 Squid, octopusAristotle's biology_cell_0_10_1 withoutAristotle's biology_cell_0_10_2 tentaclesAristotle's biology_cell_0_10_3 S, VAristotle's biology_cell_0_10_4 Cold, WetAristotle's biology_cell_0_10_5
Hard-shelled animalsAristotle's biology_cell_0_11_0 Cockle, trumpet snailAristotle's biology_cell_0_11_1 withoutAristotle's biology_cell_0_11_2 noneAristotle's biology_cell_0_11_3 S, VAristotle's biology_cell_0_11_4 Cold, Dry (mineral shell)Aristotle's biology_cell_0_11_5
Larva-bearing InsectsAristotle's biology_cell_0_12_0 Ant, cicadaAristotle's biology_cell_0_12_1 withoutAristotle's biology_cell_0_12_2 6 legsAristotle's biology_cell_0_12_3 S, VAristotle's biology_cell_0_12_4 Cold, DryAristotle's biology_cell_0_12_5
Spontaneously-generatingAristotle's biology_cell_0_13_0 Sponges, wormsAristotle's biology_cell_0_13_1 withoutAristotle's biology_cell_0_13_2 noneAristotle's biology_cell_0_13_3 S, VAristotle's biology_cell_0_13_4 Cold, Wet or Dry, from earthAristotle's biology_cell_0_13_5
PlantsAristotle's biology_cell_0_14_0 FigAristotle's biology_cell_0_14_1 withoutAristotle's biology_cell_0_14_2 noneAristotle's biology_cell_0_14_3 VAristotle's biology_cell_0_14_4 Cold, DryAristotle's biology_cell_0_14_5
MineralsAristotle's biology_cell_0_15_0 IronAristotle's biology_cell_0_15_1 withoutAristotle's biology_cell_0_15_2 noneAristotle's biology_cell_0_15_3 noneAristotle's biology_cell_0_15_4 Cold, DryAristotle's biology_cell_0_15_5

Animals with blood included live-bearing tetrapods, Zōiotoka tetrapoda (roughly, the mammals), being warm, having four legs, and giving birth to their young. Aristotle's biology_sentence_135

The cetaceans, Kētōdē, also had blood and gave birth to live young, but did not have legs, and therefore formed a separate group (megista genē, defined by a set of functioning "parts"). Aristotle's biology_sentence_136

The birds, Ornithes had blood and laid eggs, but had only 2 legs and were a distinct form (eidos) with feathers and beaks instead of teeth, so they too formed a distinct group, of over 50 kinds. Aristotle's biology_sentence_137

The egg-bearing tetrapods, Ōiotoka tetrapoda (reptiles and amphibians) had blood and four legs, but were cold and laid eggs, so were a distinct group. Aristotle's biology_sentence_138

The snakes, Opheis, similarly had blood, but no legs, and laid dry eggs, so were a separate group. Aristotle's biology_sentence_139

The fishes, Ikhthyes, had blood but no legs, and laid wet eggs, forming a definite group. Aristotle's biology_sentence_140

Among them, the selachians Selakhē (sharks and rays), had cartilages instead of bones. Aristotle's biology_sentence_141

Animals without blood were divided into soft-shelled Malakostraka (crabs, lobsters, and shrimps); hard-shelled Ostrakoderma (gastropods and bivalves); soft-bodied Malakia (cephalopods); and divisible animals Entoma (insects, spiders, scorpions, ticks). Aristotle's biology_sentence_142

Other animals without blood included fish lice, hermit crabs, red coral, sea anemones, sponges, starfish and various worms: Aristotle did not classify these into groups. Aristotle's biology_sentence_143

Scale of being Aristotle's biology_section_17

Further information: Great chain of being Aristotle's biology_sentence_144

Aristotle stated in the History of Animals that all beings were arranged in a fixed scale of perfection, reflected in their form (eidos). Aristotle's biology_sentence_145

They stretched from minerals to plants and animals, and on up to man, forming the scala naturae or great chain of being. Aristotle's biology_sentence_146

His system had eleven grades, arranged according to the potentiality of each being, expressed in their form at birth. Aristotle's biology_sentence_147

The highest animals gave birth to warm and wet creatures alive, the lowest bore theirs cold, dry, and in thick eggs. Aristotle's biology_sentence_148

The system was based on Aristotle's interpretation of the four elements in his On Generation and Corruption: Fire (hot and dry); Air (hot and wet); Water (cold and wet); and Earth (cold and dry). Aristotle's biology_sentence_149

These are arranged from the most energetic to the least, so the warm, wet young raised in a womb with a placenta were higher on the scale than the cold, dry, nearly mineral eggs of birds. Aristotle's biology_sentence_150

However, Aristotle is careful never to insist that a group fits perfectly in the scale; he knows animals have many combinations of attributes, and that placements are approximate. Aristotle's biology_sentence_151

Influence Aristotle's biology_section_18

On Theophrastus Aristotle's biology_section_19

Main article: Historia Plantarum (Theophrastus) Aristotle's biology_sentence_152

Aristotle's pupil and successor at the Lyceum, Theophrastus, wrote the History of Plants, the first classical book of botany. Aristotle's biology_sentence_153

It has an Aristotelian structure, but rather than focus on formal causes, as Aristotle did, Theophrastus described how plants functioned. Aristotle's biology_sentence_154

Where Aristotle expanded on grand theories, Theophrastus was quietly empirical. Aristotle's biology_sentence_155

Where Aristotle insisted that species have a fixed place on the scala naturae, Theophrastus suggests that one kind of plant can transform into another, as when a field sown to wheat turns to the weed darnel. Aristotle's biology_sentence_156

On Hellenistic medicine Aristotle's biology_section_20

Further information: Medicine in ancient Greece Aristotle's biology_sentence_157

After Theophrastus, though interest in Aristotle's ideas survived, they were generally taken unquestioningly. Aristotle's biology_sentence_158

It is not until the age of Alexandria under the Ptolemies that advances in biology resumed. Aristotle's biology_sentence_159

The first medical teacher at Alexandria, Herophilus of Chalcedon, corrected Aristotle, placing intelligence in the brain, and connected the nervous system to motion and sensation. Aristotle's biology_sentence_160

Herophilus also distinguished between veins and arteries, noting that the latter pulse while the former do not. Aristotle's biology_sentence_161

On Islamic zoology Aristotle's biology_section_21

Further information: Kitāb al-Hayawān and Science in the medieval Islamic world Aristotle's biology_sentence_162

Many classical works including those of Aristotle were transmitted from Greek to Syriac, then to Arabic, then to Latin in the Middle Ages. Aristotle's biology_sentence_163

Aristotle remained the principal authority in biology for the next two thousand years. Aristotle's biology_sentence_164

The Kitāb al-Hayawān (كتاب الحيوان, Book of Animals) is a 9th-century Arabic translation of History of Animals: 1–10, On the Parts of Animals: 11–14, and Generation of Animals: 15–19. Aristotle's biology_sentence_165

The book was mentioned by Al-Kindī (d. 850), and commented on by Avicenna (Ibn Sīnā) in his Kitāb al-Šifā (کتاب الشفاء, The Book of Healing). Aristotle's biology_sentence_166

Avempace (Ibn Bājja) and Averroes (Ibn Rushd) commented on On the Parts of Animals and Generation of Animals, Averroes criticising Avempace's interpretations. Aristotle's biology_sentence_167

On medieval science Aristotle's biology_section_22

Further information: Medieval science Aristotle's biology_sentence_168

When the Christian Alfonso VI of Castile retook the Kingdom of Toledo from the Moors in 1085, an Arabic translation of Aristotle's works, with commentaries by Avicenna and Averroes emerged into European medieval scholarship. Aristotle's biology_sentence_169

Michael Scot translated much of Aristotle's biology into Latin, c. 1225, along with many of Averroes's commentaries. Aristotle's biology_sentence_170

Albertus Magnus commented extensively on Aristotle, but added his own zoological observations and an encyclopedia of animals based on Thomas of Cantimpré. Aristotle's biology_sentence_171

Later in the 13th century, Thomas Aquinas merged Aristotle's metaphysics with Christian theology. Aristotle's biology_sentence_172

Whereas Albert had treated Aristotle's biology as science, writing that experiment was the only safe guide and joining in with the types of observation that Aristotle had made, Aquinas saw Aristotle purely as theory, and Aristotelian thought became associated with scholasticism. Aristotle's biology_sentence_173

The scholastic natural philosophy curriculum omitted most of Aristotle's biology, but included On the Soul. Aristotle's biology_sentence_174

On Renaissance science Aristotle's biology_section_23

Renaissance zoologists made use of Aristotle's zoology in two ways. Aristotle's biology_sentence_175

Especially in Italy, scholars such as Pietro Pomponazzi and Agostino Nifo lectured and wrote commentaries on Aristotle. Aristotle's biology_sentence_176

Elsewhere, authors used Aristotle as one of their sources, alongside their own and their colleagues' observations, to create new encyclopedias such as Konrad Gessner's 1551 Historia Animalium. Aristotle's biology_sentence_177

The title and the philosophical approach were Aristotelian, but the work was largely new. Aristotle's biology_sentence_178

Edward Wotton similarly helped to found modern zoology by arranging the animals according to Aristotle's theories, separating out folklore from his 1552 De differentiis animalium. Aristotle's biology_sentence_179

Early Modern rejection Aristotle's biology_section_24

In the Early Modern period, Aristotle came to represent all that was obsolete, scholastic, and wrong, not helped by his association with medieval theology. Aristotle's biology_sentence_180

In 1632, Galileo represented Aristotelianism in his Dialogo sopra i due massimi sistemi del mondo (Dialogue Concerning the Two Chief World Systems) by the strawman Simplicio ("Simpleton"). Aristotle's biology_sentence_181

That same year, William Harvey proved Aristotle wrong by demonstrating that blood circulates. Aristotle's biology_sentence_182

Aristotle still represented the enemy of true science into the 20th century. Aristotle's biology_sentence_183

Leroi noted that in 1985, Peter Medawar stated in "pure seventeenth century" tones that Aristotle had assembled "a strange and generally speaking rather tiresome of hearsay, imperfect observation, wishful thinking and credulity amounting to downright gullibility". Aristotle's biology_sentence_184

19th century revival Aristotle's biology_section_25

Zoologists working in the 19th century, including Georges Cuvier, Johannes Peter Müller, and Louis Agassiz admired Aristotle's biology and investigated some of his observations. Aristotle's biology_sentence_185

D'Arcy Thompson translated History of Animals in 1910, making a classically-educated zoologist's informed attempt to identify the animals that Aristotle names, and to interpret and diagram his anatomical descriptions. Aristotle's biology_sentence_186

Darwin quoted a passage from Aristotle's Physics II 8 in The Origin of Species, which entertains the possibility of a selection process following the random combination of body parts. Aristotle's biology_sentence_187

However, Aristotle immediately rejected the possibility, and he was in any case discussing ontogeny, the Empedoclean coming into being of an individual from component parts, not phylogeny and natural selection. Aristotle's biology_sentence_188

20th and 21st century interest Aristotle's biology_section_26

Zoologists have frequently mocked Aristotle for errors and unverified secondhand reports. Aristotle's biology_sentence_189

However, modern observation has confirmed one after another of his more surprising claims, including the active camouflage of the octopus and the ability of elephants to snorkel with their trunks while swimming. Aristotle's biology_sentence_190

Aristotle remains largely unknown to modern scientists, though zoologists are perhaps most likely to mention him as "the father of biology"; the MarineBio Conservation Society notes that he identified "crustaceans, echinoderms, mollusks, and fish", that cetaceans are mammals, and that marine vertebrates could be either oviparous or viviparous, so he "is often referred to as the father of marine biology". Aristotle's biology_sentence_191

The evolutionary zoologist Armand Leroi has taken an interest in Aristotle's biology. Aristotle's biology_sentence_192

The concept of homology began with Aristotle, and the evolutionary developmental biologist Lewis I. Aristotle's biology_sentence_193 Held commented that Aristotle's biology_sentence_194

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