Lecture 13 : The Classification of Living Organisms تصنيف الكائنات الحية

1. Lecture 13: The Classification of Living Organisms تصنيف الكائنات الحية • Taxonomyعلم التصنيف • Taxonomy: is that branch of biology, concerned with the grouping and namingتسميةof organisms. • The modern taxonomic system was developed by the Swedish botanist Carolus Linnaeus كارلوس لينيوس(1707-1788). • Heclassified 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 شعبةطائفةرتبةعائلة جنسنوع

2. 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 وايتكرin 1969 proposed five kingdoms: 1) Kingdom: Animalia مملكة الحيوان 3) Kingdom: Fungi مملكة الفطريات 5)Kingdom: Monera مملكة البدائيات 2)Kingdom: Plantae مملكة النبات 4)Kingdom: Protista مملكة الطلائعيات

3. 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”.

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

5. 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 habitatsالموطنthat are too cold, too hot, too salty, too acidic, or too alkaline.

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

7. 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

8. A) Bacteria • Bacteria can be classified by shape intoBacillus عصوية, Coccus كرويةor 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 intestinesأمعائناproduce important vitamins. • Bacteria recycle CO2 and other chemical elements between organic matter and the soil and atmosphere.

9. B) Archaea Archaea can be classified into: a)- Halophilesمحب 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 الينابيع). • The optimum temperatures for most thermophiles are 60 - 80°C.