biodiversity of animals invertebrates
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The document discusses early embryonic development and the biodiversity of animals, focusing on invertebrates. It describes how a zygote undergoes cleavage and forms a blastula through gastrulation. It then classifies animals into phyla based on their body plan, discussing characteristics like symmetry, tissues, and protostome vs deuterostome development. Major phyla include porifera, cnidaria, platyhelminthes, nematoda, annelida, arthropoda, mollusca, echinodermata, and chordata.
biodiversity of animals invertebrates
- 1. UNIT 4: BIODIVERSITY OF ANIMALS: INVERTEBRATES ( Campbell and Reece, 2010: Chapter 32 and 33)
- 2. Welcome to Your Kingdom • The animal kingdom extends far beyond humans and other animals we may encounter • 1.3 million living species of animals have been identified • Invertebrates (animals that lack a backbone) account for 95% of known animal species.
- 3. EARLY EMBRYONIC DEVELOPMENT IN ANIMALS Most animals reproduce sexually, with the diploid stage usually dominating the life cycle After a sperm fertilizes an egg, the zygote undergoes rapid cell division called cleavage Cleavage leads to formation of a blastula The blastula undergoes gastrulation, forming a gastrula with different layers of embryonic tissues.
- 4. Fig. 32-2-1 EARLY EMBRYONIC DEVELOPMENT IN ANIMALS Cleavage Zygote Eight-cell stage
- 5. Fig. 32-2-1 32-2-2 EARLY EMBRYONIC DEVELOPMENT IN ANIMALS Blastula Cleavage Cleavage Cleavage Eight-cell stage ygote Zygote Eight-cell stage Blastocoel Cross section of blastula
- 6. Fig. 32-2-1 32-2-2 Fig. 32-2-3 EARLY EMBRYONIC DEVELOPMENT IN ANIMALS Blastula Blastocoel Cleavage Cleavage Cleavage Cleavage Cleavage Endoderm Ectoderm Blastula Eight-cell stage Archenteron Zygote ygote Eight-cell stage Zygote Eight-cell stage Gastrula Blastocoel Blastocoel Blastopore Cross section of Cross section blastula of blastula Gastrulation
- 7. • Many animals have at least one larval stage. • A larva is sexually immature and morphologically distinct from the adult; it eventually undergoes metamorphosis.
- 8. 2. RELATIONSHIP BETWEEN BODY PLAN AND GROUPING OF ANIMALS IN PHYLA • Zoologists sometimes categorize animals according to a body plan. • A body plan is a set of morphological and developmental traits, integrated into a functional whole living animal.
- 9. CHARACTERISTICS WHICH EXPLAIN BODY PLAN • • • • • Symmetry Cephalization Tissues) Body cavities Protostome and Deuterostome development
- 10. A. SYMMETRY • Animals can be categorized according to the symmetry of their bodies, or lack of it • Some animals have radial symmetry • Two-sided symmetry is called bilateral symmetry
- 12. Bilaterally symmetrical animals have: – A dorsal (top) side and a ventral (bottom) side – A right and left side – Anterior (head) and posterior (tail) ends
- 13. B. CEPHALIZATION • Cephalization, the development of a head
- 14. C. TISSUES • Animal body plans also vary according to the organization of the animal’s tissues • Tissues are collections of specialized cells • During development, three germ layers give rise to the tissues and organs of the animal embryo
- 15. GERM LAYERS ARE: • Ectoderm is the germ layer covering the embryo’s surface • Endoderm is the innermost germ layer and lines the developing digestive tube, called the archenteron • Mesoderm: middle layer of some body plans
- 16. • Diploblastic animals have ectoderm and endoderm • Triploblastic animals have an ectoderm, endoderm and intervening mesoderm layer.
- 17. D. BODY CAVITIES • Most triploblastic animals possess a body cavity • A true body cavity is called a coelom and is derived from mesoderm • Coelomates are animals that possess a true coelom • A pseudocoelom is a body cavity derived from the mesoderm and endoderm • Triploblastic animals that possess a pseudocoelom are called pseudocoelomates • Triploblastic animals that lack a body cavity are called acoelomates
- 19. E. PROTOSTOME AND DEUTEROSTOME DEVELOPMENT • Based on early development, many animals can be categorized as having protostome development or deuterostome development • These two types of developments differ in regard to: • Different cleavage • Different coelom formation • Fate of the blastopore
- 20. CLEAVAGE • In protostome development, cleavage is spiral and determinate • In deuterostome development, cleavage is radial and indeterminate • With indeterminate cleavage, each cell in the early stages of cleavage retains the capacity to develop into a complete embryo
- 22. COELOM FORMATION • In protostome development, the splitting of solid masses of mesoderm forms the coelom. • In deuterostome development, the mesoderm buds from the wall of the archenteron to form the coelom.
- 24. FATE OF THE BLASTOPORE • The blastopore forms during gastrulation and connects the archenteron to the exterior of the gastrula • In protostome development, the blastopore becomes the mouth • In deuterostome development, the blastopore becomes the anus
- 27. 3. SYNOPTIC CLASSIFICATION OF THE ANIMAL KINGDOM Kingdom: Animalia Branch 1: Mesozoa (fish parasites) Branch 2: Parazoa (cellular) Phylum: Porifera (sponges) Branch 3: Eumetazoa (multicellular)
- 28. Branch 3: Eumetazoa (multicellular) • Grade 1: Radiata (Radial symmetry, tissue level) Phylum: Cnidaria hydras corals sea-anemones • Grade 2: Bilateria (Bilateral symmetry, organ level, cephalisation)
- 29. Grade 2: Bilateria (Bilateral symmetry, organ level, cephalisation) • Division 1: Protostomia • Division 2: Deuterostomia
- 30. Division 1: Protostomia • Group 1: Acoelomata (no body cavity) Phylum: Platyhelminthes (flat worms) • Group 2: Pseudocoelomata (pseudo body cavity) Phylum: Nematoda (round worms) • Group 3: Eucoelomata Phylum: Annelida (earthworms, leeches: Metamerism) Phylum: Arthropoda (crabs, insects: Tagmatisation) Phylum: Mollusca (slugs, snails)
- 31. Division 2: Deuterostomia Phylum: Echinodermata sea stars seaurchins Phylum: Chordata (vertebrates)
- 32. SUMMARY OF PHYLA • • • • • • • • Phylum: Phylum: Phylum: Phylum: Phylum: Phylum: Phylum: Phylum: urchins) • Phylum: Porifera (sponges) Cnidaria (Hydra, sea anemones) Platyhelminthes (flat worms) Nematoda (round worms) Annelida (earthworms, leeches) Arthropoda (crabs, insects) Mollusca (slugs, snails) Echinodermata (sea stars, sea Chordata (vertebrates)
- 33. Phylum: Porifera (sponges) • Sedentary animals (fixed in one position) • They live in both fresh and marine waters • Cellular level of development • Lack true tissues and organs • Asymmetrical
- 34. Phylum:Cnidaria (Hydra, sea anemones) • True tissue – Eumetazoa • Both sessile and motile forms including jellies, corals, and hydras • Diploblastic body plan • Radial symmetry • The basic body plan of a cnidarian is a sac with a central digestive compartment, the gastrovascular cavity • A single opening functions as mouth and anus
- 35. • Carnivores that use tentacles to capture prey • The tentacles are armed with cnidocytes, unique cells that function in defense and capture of prey • Nematocysts are specialized organelles within cnidocytes that eject a stinging thread.
- 36. Phylum: Platyhelminthes (flat worms) • Live in marine, freshwater, and damp terrestrial habitats. • Triploblastic development • Acoelomates • Flattened dorsoventrally and have a gastrovascular cavity • Gas exchange takes place across the surface • Protonephridia regulate the osmotic balance
- 37. Phylum: Nematoda (round worms) • Found in most aquatic habitats, in the soil, in moist tissues of plants, and in body fluids and tissues of animals • They have an alimentary canal, but lack a circulatory system • Sexual Reproduction • Internal fertilization • Some species are parasites of plants and animals.
- 38. Phylum: Annelida (earthworms, leeches) • Bodies composed of a series of fused rings or compartments - Metamerism
- 39. Phylum: Arthropoda (crabs, insects) • Found in nearly all habitats of the biosphere The arthropod body plan consists of a segmented body, hard exoskeleton (made of layers of protein and the polysaccharide chitin jointed appendages • The body is completely covered by the cuticle • When it grows, it molts its exoskeleton. • Includes: insects, crabs, spiders, millipedes, centipedes, mites…
- 41. Phylum: Mollusca (slugs, snails) • Includes snails and slugs, oysters and clams, and octopuses and squids • Most are marine, some inhabit fresh water and some are terrestrial • Soft bodied animals, but most are protected by a hard shell.
- 42. Phylum: Echinodermata (sea stars, sea urchins) • Shared characteristics define deuterostomes (Chordates and Echinoderms) – Radial cleavage – Formation of the mouth at the end of the embryo opposite the blastopore • Echinoderms have a unique water vascular system, a network of hydraulic canals branching into tube feet that function in locomotion, feeding, and gas exchange
- 44. Phylum: Chordata (vertebrates) • Phylum Chordata consists of two subphyla of invertebrates as well as hagfishes and vertebrates • Vertebrates are a subphylum within the phylum Chordata • Chordates are bilaterian animals that belong to the Deuterostomia. • All chordates share a set of derived characters • Some species have some of these traits only during embryonic development
- 45. Four key characteristics of chordates – Notochord – Dorsal, hollow nerve cord – Pharyngeal slits or clefts – Muscular, post-anal tail