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This is the complete lecture note for ZOO 212 Invertebrate Zoology II. You can read it online below, open it in the full viewer, or download the PDF for offline study. It pairs with the course's video lectures, so you can read and watch together.
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LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS ZOO 212: Invertebrate Zoology II (2 Units C: LH 15; PH 45) Course Code: ZOO 212 Course Title: Invertebrate Zoology II Course Unit: 2 Units C Series 1: Taxonomy And Organisation Of Ectoprocta (Bryozoa) Series 2: Morphology And Evolutionary Significance Of Brachiopoda Series 3: Organisation And Life Processes Of Phoronida Series 4: Structural Diversity And Ecological Roles Of Annelida And Mollusca Series 5: Systematics And Evolutionary Importance Of Arthropoda And Echinodermata Series 1: Taxonomy And Organisation Of Ectoprocta (Bryozoa) Part 1.1 General features and classification of Ectoprocta (Bryozoa) 1.1.1 Definition and scope of Bryozoa 1.1.2 General features and body plan 1.1.3 Major classes and representative examples Part 1.2 Morphology and organisation of Bryozoa 1.2.1 Colony structure and zooids 1.2.2 Feeding structures and lophophore 1.2.3 Reproductive strategies and life cycle Part 1.3 Ecological roles and evolutionary significance of Bryozoa 1.3.1 Role in aquatic ecosystems 1.3.2 Fossil record and evolutionary importance Introduction Ectoprocta, commonly known as Bryozoa, are fascinating colonial invertebrates that often resemble delicate mosses growing on rocks, shells, or submerged surfaces. Despite their small size, they play important roles in aquatic ecosystems and provide valuable insights into
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS evolutionary history. Studying them helps us appreciate the diversity of higher invertebrates and their contributions to biodiversity. The aim of this Series is to introduce you to the taxonomy and organisation of Bryozoa, enabling you to classify them, describe their morphology, and explain their ecological and evolutionary significance. We shall commence this Series by examining the general features and classification of Bryozoa. Next, we will explore their morphology and organisation, focusing on colony structure, feeding mechanisms, and reproductive strategies. Finally, we will conclude by analysing their ecological roles and evolutionary importance, including their contributions to aquatic ecosystems and the fossil record. Series Learning Outcomes Upon completing this Series, you should be able to: SLO 1.1 define Bryozoa and explain their scope, SLO 1.2 describe the general features and body plan of Bryozoa, SLO 1.3 classify Bryozoa into major groups with examples, SLO 1.4 analyse the morphology and organisation of Bryozoa colonies, SLO 1.5 explain the feeding structures and reproductive strategies of Bryozoa, and SLO 1.6 evaluate the ecological roles and evolutionary significance of Bryozoa. 1.1 General Features And Classification Of Ectoprocta (Bryozoa) 1.1.1 Definition and scope of Bryozoa Bryozoa, also known as Ectoprocta, are small, aquatic, colonial invertebrates that often resemble mosses growing on submerged surfaces. They are sessile, meaning they remain attached to substrates such as rocks, shells, or seaweed. Each colony is made up of numerous individuals called zooids, which are interconnected and function together. The scope of Bryozoa includes their structural organisation, feeding mechanisms, reproduction, and their role in aquatic ecosystems. Short description: Diagram showing a Bryozoan colony with zooids attached to a substrate. Caption: Figure 1.1 General features of Bryozoa Fill in the blank: Bryozoa are colonial invertebrates made up of numerous interconnected ______. 1.1.2 General features and body plan
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Bryozoa are characterised by their lophophore, a crown of ciliated tentacles used for feeding and respiration. Each zooid has a protective outer casing called the exoskeleton, which may be calcareous or chitinous. The body plan is simple, with a U-shaped digestive tract that allows food to enter through the mouth and waste to exit near the same region. Bryozoans are coelomates, possessing a true body cavity, and they exhibit bilateral symmetry. Short description: Diagram showing the body plan of a Bryozoan zooid with lophophore and U-shaped digestive tract. Caption: Figure 1.2 Body plan of a Bryozoan zooid Fill in the blank: The crown of ciliated tentacles used for feeding in Bryozoa is called the ______. 1.1.3 Major classes and representative examples Bryozoa are classified into three major classes based on their structural organisation and habitat: Class Phylactolaemata: Freshwater Bryozoans, e.g., Cristatella. Class Gymnolaemata: Marine Bryozoans, often encrusting surfaces, e.g., Bugula. Class Stenolaemata: Marine Bryozoans with tubular zooids, e.g., Tubulipora. This classification highlights the diversity of Bryozoa across freshwater and marine environments. Table 1.3 Major classes of Bryozoa with examples
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Class Habitat Key Characteristics Representative Examples Phylactolaemata Freshwater (Lakes, ponds, and slow-moving rivers). Possess a horseshoe-shaped lophophore; produce dormant overwintering capsules called statoblasts. Non-calcified. Plumatella, Cristatella mucedo. Stenolaemata Exclusively Marine (Deep sea to coastal). Tubular, heavily calcified zooecia (skeletons); lophophore is circular. Most are extinct (Paleozoic), but one order (Cyclostomatida) survives. Tubulipora, Crisia. Gymnolaemata Mostly Marine (Some brackish water). The most diverse class; zooecia are box-like or cylindrical; lophophore is circular. Often possess specialized polymorphic zooids (e.g., avicularia). Bugula, Membranipora, Electra. Fill in the blank: Freshwater Bryozoans such as Cristatella belong to the class ______. Pilot questions 1.1 What are Bryozoa also known as? What is the name of the individual units that make up a Bryozoan colony? What feeding structure is characteristic of Bryozoa? Name the three major classes of Bryozoa. Which class of Bryozoa includes freshwater species? 1.2 Morphology And Organisation Of Bryozoa 1.2.1 Colony structure and zooids Bryozoa are colonial organisms, meaning they live in groups rather than as solitary individuals. Each colony is composed of numerous zooids, which are small individual units that function together. Zooids are interconnected by tissue or stolons, allowing communication and resource sharing across the colony. Colonies may take different forms, including encrusting sheets,
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS branching structures, or even gelatinous masses. This colonial organisation provides strength, stability, and efficiency in feeding. Short description: Diagram showing different colony forms of Bryozoa with zooids interconnected. Caption: Figure 1.4 Colony structure of Bryozoa Fill in the blank: The individual units that make up a Bryozoan colony are called ______. 1.2.2 Feeding structures and lophophore Bryozoa feed using a specialised structure called the lophophore, which is a crown of ciliated tentacles. The lophophore generates water currents that draw plankton and organic particles towards the mouth. The U-shaped digestive tract ensures that food enters through the mouth and waste exits near the same region, making feeding efficient. The lophophore also plays a role in respiration by facilitating gas exchange. Short description: Diagram showing the lophophore of Bryozoa with ciliated tentacles and feeding currents. Caption: Figure 1.5 Feeding structures of Bryozoa Fill in the blank: The crown of ciliated tentacles used for feeding in Bryozoa is called the ______. 1.2.3 Reproductive strategies and life cycle
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Bryozoa reproduce both sexually and asexually. In sexual reproduction, zooids produce gametes, and fertilisation usually occurs internally. The fertilised eggs develop into larvae, which disperse and settle to form new colonies. Asexual reproduction occurs through budding, where new zooids are formed from existing ones, allowing colonies to expand rapidly. This dual reproductive strategy ensures survival and adaptability in diverse environments. Short description: Diagram showing the life cycle of Bryozoa including larval dispersal and colony formation. Caption: Figure 1.6 Life cycle of Bryozoa Fill in the blank: In Bryozoa, new zooids are formed from existing ones through a process called ______. Pilot questions 1.2 What are the individual units of a Bryozoan colony called? What feeding structure is characteristic of Bryozoa? How does the lophophore assist in respiration? Name one method of asexual reproduction in Bryozoa. What type of digestive tract is found in Bryozoa? 1.3 Ecological Roles And Evolutionary Significance Of Bryozoa 1.3.1 Role in aquatic ecosystems Bryozoa play an important role in aquatic ecosystems as filter feeders. Their lophophore, a crown of ciliated tentacles, helps them capture plankton and organic particles from the water, thereby improving water quality. Colonies often form encrusting layers on rocks, shells, and submerged surfaces, providing habitats for other small organisms. In addition, Bryozoa contribute to the structural complexity of aquatic environments, supporting biodiversity. Short description: Diagram showing Bryozoan colonies encrusting rocks and shells in an aquatic ecosystem. Caption: Figure 1.7 Ecological roles of Bryozoa Fill in the blank: Bryozoa improve water quality by capturing plankton and organic particles using their ______. 1.3.2 Fossil record and evolutionary importance
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Bryozoa have a rich fossil record, dating back to the Ordovician period. Their calcareous skeletons are well preserved in marine sediments, making them useful in studying past environments. Fossil Bryozoa provide evidence of evolutionary trends, including changes in colony structure and skeletal composition. They are also important in biostratigraphy, helping geologists to date rock layers. Evolutionarily, Bryozoa demonstrate the development of colonial organisation and lophophorate feeding structures, which are significant in understanding the diversification of coelomate invertebrates. Box 1.8 Fossil and evolutionary significance of Bryozoa Evolutionary Milestone Description and Significance Late Appearance Unlike most phyla that appeared in the Cambrian Explosion, Bryozoans first appear in the Early Ordovician. This suggests a period of "hidden" evolution
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