Lecture 14: Animal Classification

1. Eukaryota 3 1 2 Prokaryota Lecture 14: Animal Classification 2- Kingdom Protistaالأوليات (Eukaryotic uni-/multi-cellular) • In the five-kingdom system of classification, the eukaryotes were distributed among four kingdoms: Protista, Plantae, Fungi, and Animalia. • Protists are eukaryotes and thus are much more complex than the prokaryotes. • The first eukaryotes were unicellular. • eukaryotic and multi-cellular animals originated from protists.

2. Protists • Protista (mostly unicellular eukaryotes) ranging from uni-celled microscopic members, simple multi-cellular forms, and complex giants like seaweedsحشائش البحر. • Still,“protist” is used as a term for a great diversity of eukaryotic kingdoms. • Most of the 60,000 known protists are unicellular, but some are colonial مستعمرات and others multi-cellular. • Many protists form resistant cells (cysts حوصلة) that can survive harsh conditions.

3. Characters of Protistsصفات الأوليات A)- Nutritionالتغذية : • Most protists are aerobicهوائية التنفس , with mitochondria for cellular respiration. • Some protists are photoautotrophs with chloroplasts. • Still others are heterotrophs that absorb organic molecules or ingest larger food particles. • A few are mixotrophs, combining photosynthesis and heterotrophic nutrition. • Protists may include photosynthetic species, heterotrophic species, and mixotrophic species.

4. Protists B)- Movementالحركة : - Most protists move with flagellaالأسواط or ciliaالأهداب during some time in their life cycles. - The eukaryotic flagella are not homologous to those of prokaryotes. • The eukaryotic flagella are extensions of the cytoplasm with a support of the 9 + 2 microtubule system. • Cilia are shorter and more numerous than flagella. • Cilia and flagella move the cell with rhythmic power strokes, analogous to the oars of a boat. C)- Reproductionالتكاثر : - Reproduction and life cycles are highly variedمتنوع among protists. Mitosis occurs in almost all protists. - Some protists are asexualلاجنسية . - Others are primarily asexual but can also reproduce sexually occasionally.

5. Protists F)- Importanceالأهمية : • Many protists are symbiontsمتطفلة that inhabit the body fluids, tissues, or cells of hostsالعائل . • These symbiotic relationships span the continuum from mutualism to parasitism. • Some parasitic protists are important pathogens of animalsممرضات للحيوان , including those that cause potentially fatal diseases in humans.

6. Protists (e.g. Euglena) G)- Example of Protista: Systematic Positionالوضع التقسيمي Kingdom: Protista الأوليات Subkingdom: Protozoaتحت مملكة (عويلم) الأوليات الحيوانية Phylum: Protozoa شعبةالأوليات الحيوانية Subphylum: Mastigophoraتحت شعبة (شعيبة) السوطيات example: Euglenaاليوجلينا • a single-celled mixotrophic متعدد الغذاءprotist, • can use chloroplasts to undergo photosynthesis if light is available • or live as a heterotroph by absorbing organic nutrients from the environment. • Reproduce asexually by “binary fission”. • Sometimes form resistant cells (cysts) that can survive harsh conditions.

7. سوط مستشعر ضوئي فجوة منقبضة النواة بلاستيدة خضراء الغشاء البلازمي أشرطة بروتينية حبيبات 1. Protists use flagella (flagellates) for movement Euglena بقعة عينية

8. 2- Trypanosomaالتريبانوسوما • Trypanosoma : is symbiotic and include pathogenic parasites. causes African sleeping sickness. Systematic Position Kingdom: Protista Subkingdom: Protozoa Phylum: Protozoa Subphylum: Mastigophora example:Trypanosoma • It is pathogenic parasite • causes African sleeping sickness مرض النوم الأفريقي

9. 3. Parasitic Protists: Apicomplexansمعقدة القمة • All apicomplexans are parasites of animals and some cause serious human diseases. • The parasites are tiny infectious cellsخلايا صغيرة ممرضة(sporozoites) with a complex of organelles specialized for penetratingاختراق host cells and tissues at the apexقمة of the sporozoite cell. • Most apicomplexans have life cycles with both sexual and asexual stages and often require two or more different host species for completion. • Plasmodium, the parasite that causes malaria, spends part of its life in mosquitoes and part in humans.

10. Kingdom: Protista Subkingdom: Protozoa Phylum: Protozoa 2- Subphylum: Sporozoa example: Plasmodium بلازموديوم الملاريا Subphylum: Sporozoa البوغيات الطور المعدي الحويصلات الجرثومية الحويصلات البيضية

11. Subphylum: Ciliophoraالهدبيات , Protists use ciliaأهداب for movement • The Ciliophora (ciliates), a diverse protist group, is named for their use of cilia to move and feed. • Most ciliates live in freshwater. • Their cilia coordinate movement. • Some ciliates are completely covered by rows of cilia, whereas others have cilia clustered into fewer rows. • The specific arrangement of cilia adapts the ciliates for their lifestyles.

12. الأهداب الفجوة الغذائية الميزاب الفمي النواة الصغيرة النواة الكبيرة الفجوة المنقبضة Subphylum: Ciliophora شعيبة الهدبيات • Paramecium: has cilia along the oral grooveالميزاب الفمي draw in foodيبلع الغذاء that are engulfed by phagocytosis, and expelsويُخرج accumulated water from the contractile vacuoleالفجوة المنقبضة .

13. Paramecium • Parameciumhas two types of nuclei, a large macronucleus and usually several tiny micronuclei. • Paramecium generally reproduce asexually by binary fission of the macronucleus, rather than mitotic division. • The micronuclei (with between 1 and 80 copies) are required for sexual processes that generate genetic variation.

14. 4. Subphylum: Sarcodinaالسركودينا Protists use pseudopodia الأقدام الكاذبة for movement and feeding • Sarcodina are protists use pseudopodia, cellular extensions, to move and often to feed. • Most species are heterotrophs that actively feed on bacteria and other protists. • Other species are symbiotic, including some human parasites. • Amoebas are all unicellular and use pseudopodia to move and to feed. • Amoeboid movementالحركة الأميبية occurs by changes in microtubules and microfilaments in the cytoskeleton. • Pseudopodia activity is directed toward food.

15. Amoebas inhabit freshwater and marine environments • They may also be abundant in soils. • Most species are free-living heterotrophs. • Some are important parasites. • These include Entamoeba histolytica which causes amoeboid dysentery مرض الدوسنتاريا in humans. • These organisms spread by contaminated drinking water, food, and eating utensils.