Lecture 13: The Classification of Living Organisms تصنيف الكائنات الحية Taxonomy علم التصنيف Taxonomy: is that branch of biology, concerned with the grouping and namingتسمية of organisms. The modern taxonomic system was developed by the Swedish botanist Carolus Linnaeus كارلوس لينيوس (1707-1788). He classified all known organisms into two large kingdoms: a) Kingdom Plantae المملكة النباتية b) Kingdom Animalia المملكة الحيوانية Linnaeus developed a 7 level classification system based on similarities between organisms. Kingdom Phylum Class Order Family Genus Species مملكة شعبة طائفة رتبة عائلة جنس نوع

Linnaeus classified species as the smallest unit. Species is a Latin word meaning “kind” or “appearanceالشكل الظاهري ” Differences between species based on: Morphological differencesاختلافات شكلية The potential to interbreedالقدرة على التزاوج with each other in nature to produce fertile offspringنسل خصيب Robert Whittaker روبرت وايتكر in 1969 proposed five kingdoms: 1) Kingdom: Animalia مملكة الحيوان 2) Kingdom: Plantae مملكة النبات 4) Kingdom: Protista مملكة الطلائعيات 5) Kingdom: Monera مملكة البدائيات 3) Kingdom: Fungi مملكة الفطريات

Binomial nomenclature التسمية الثنائية Developed by Carolus Linnaeus. Binomial nomenclature consists of two names: The first name is the organism’s genus The second name is the organism’s species What rules are used to write scientific names? The first letter of the genus is always capitalized. The first letter of the species is always lowercase. Scientific names of organisms are always italicized or underlined. For example, Linnaeus assigned to humans the scientific name Homo sapiens, which means “wise man الإنسان العاقل”.

Systematic position of human الوضع التقسيمي للإنسان Kingdom: Animaliaالمملكة الحيوانية Phylum: Chordataشعبة الحبليات Class: Mammaliaطائفة الثدييات Order: Primatesرتبة الرئيسيات Family: Hominidaeعائلة البشر Genus: Homo الجنس البشري Species: sapiensالإنسان

First: Kingdom of Monera مملكة البدائيات All the organisms of this kingdom are prokaryotes .بدائية النواةThis means all cells do not have nuclear membrane. They are unicellular organisms كائنات وحيدة الخلية The kingdom is divided into two groups, a) Bacteria and b) Archaea. Monera exist in habitatsالموطن that are too cold, too hot, too salty, too acidic, or too alkaline.

Classification of Kingdom Monera Based on Mode of Nutrition طريقة التغذية 1) Autotrophs ذاتي التغذية 2) Heterotrophs غير ذاتي التغذية a) Saprophyte ترمم b) Parasitism تطفل c) Symbiosis تكافل i) Mutualism تقايض ii) Commensalism تعايش

Autotrophic bacteria: bacteria which prepare their own food. Heterotrophic bacteria: bacteria which are dependent on other organisms for their food. Parasitic bacteria: bacteria obtain their food from the tissues of living organisms (host العائل) and cause harm to the host. Saprophytic bacteria: bacteria obtain their food from dead organic matter. Mutualism: a relationship between individuals of different species in which both individuals benefit. Commensalism: a relationship between individuals of different species in which one organism benefits without affecting the other

A) Bacteria Bacteria can be classified by shape into Bacillus عصوية, Coccus كروية or Spirillum حلزونية. Different types of diseases are caused by bacteria include: cholera, many sexually diseases الأمراض الجنسية, and certain types of food poisoningالتسمم الغذائي However, more bacteria are beneficial مفيدة . Bacteria in our intestinesأمعائنا produce important vitamins. Bacteria recycle CO2 and other chemical elements between organic matter and the soil and atmosphere.

B) Archaea Archaea can be classified into: a)- Halophiles محب للملوحة live in saline waters (high salt concentrations) as the Great Salt Lake and the Dead Sea. Some species require an extremely salty environment to grow. b)- Thermophilesمحب للحرارة live in hot environments (hot springs). The optimum temperatures for most thermophiles are 60 - 80°C.