Biology Practical 2 (PDF)

Biology practical 2 First class, Second semester Ass. Lec.Dunya.A.Mohammed Lab 4 Kingdom of animals The characteristics of the animal kingdom :- Cell Structure: Animals are multicellular organisms, meaning they are composed of more than one cell. These...

Biology practical 2 First class, Second semester Ass. Lec.Dunya.A.Mohammed Lab 4 Kingdom of animals The characteristics of the animal kingdom :- Cell Structure: Animals are multicellular organisms, meaning they are composed of more than one cell. These cells are eukaryotic, containing membrane-bound organelles such as nuclei. Body Symmetry: Animals can exhibit different types of body symmetry. Some, like humans, exhibit bilateral symmetry, where the body can be divided into two equal halves. Others, like jellyfish, display radial symmetry, where body parts are arranged around a central axis. Tissue Organization: Animals have specialized tissues that perform specific functions. These tissues may form organs and organ systems, such as the digestive system, circulatory system, and nervous system. Reproduction: Most animals reproduce sexually, although some can reproduce asexually. Sexual reproduction involves the fusion of gametes (sperm and egg) to form a zygote, which develops into a new organism. Asexual reproduction involves the production of offspring without the fusion of gametes. Development: Animals undergo embryonic development, starting from a single fertilized egg cell (zygote) that divides and differentiates into specialized cells, tissues, and organs. Classifications of animal kingdom: Phylum Porifera (Sponges): Sponges are simple multicellular animals characterized by their porous bodies. They are filter feeders, drawing in water through pores and extracting nutrients. 1 Biology practical 2 First class, Second semester Ass. Lec.Dunya.A.Mohammed Lab 4 Phylum Cnidaria (Jellyfish, Corals): Cnidarians exhibit radial symmetry and possess specialized stinging cells called cnidocytes. Examples include jellyfish, corals, and sea anemones. Phylum Platyhelminthes (Flatworms): Flatworms are dorsoventrally flattened worms with simple organ systems. They include parasites like tapeworms and free-living species like planarians. Phylum Mollusca (Mollusks): Mollusks are soft-bodied animals with a muscular foot and often a protective shell. Examples include snails, clams, octopuses, and squid. Phylum Arthropoda (Arthropods): Arthropods are the largest phylum in the animal kingdom and include insects, arachnids (spiders, scorpions), crustaceans (crabs, shrimp), and myriapods (centipedes, millipedes). They are characterized by their segmented bodies, exoskeletons, and jointed appendages. Phylum Chordata (Chordates): Chordates are characterized by the presence of a notochord, dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail at some stage of their development. This phylum includes vertebrates (animals with a backbone) and invertebrate chordates like tunicates and lancelets. Benefits of Animals 1- Ecosystem Services: Pollination: Many animals, particularly insects like bees and butterflies, play a crucial role in pollinating flowering plants, thereby facilitating reproduction and the production of fruits and seeds. Seed Dispersal: Animals such as birds, mammals, and even ants help disperse seeds of plants, contributing to the regeneration of forests and the maintenance of biodiversity. Nutrient Cycling: Animals, especially decomposers like bacteria, fungi, and detritivores, help break down organic matter, returning essential nutrients to the soil and contributing to 2 Biology practical 2 First class, Second semester Ass. Lec.Dunya.A.Mohammed Lab 4 nutrient cycling. 2- Food and Agriculture: Livestock: Animals such as cows, pigs, chickens, and sheep are raised for meat, milk, eggs, and other products, providing a major source of protein and nutrients in human diets. Fisheries: Fish and other aquatic organisms are harvested from oceans, rivers, and lakes, providing a significant source of protein and essential fatty acids for human consumption. 3- Scientific and Medical Research: Biomedical Research: Animals are used in scientific research to study diseases and develop treatments contributing to improve in human and animal health. Model Organisms: Certain animals, like mice, fruit flies, and zebrafish, are used as model organisms in biomedical research due to their genetic similarity to humans and ease of manipulation in laboratory settings. Harmful of Animals While animals provide numerous benefits, there are also instances where they can have harmful effects. Here are some examples of the harmful aspects of animals: Disease Transmission: Animals can serve as vectors for various diseases that can affect humans and other animals. For example, mosquitoes transmit diseases like malaria while rodents can carry diseases such as hantavirus. Zoonotic diseases, which originate in animals and are transmitted to humans, can have significant public health impacts. Examples include COVID-19, Ebola, and avian influenza. 3 Biology practical 2 First class, Second semester Ass. Lec.Dunya.A.Mohammed Lab 4 Differences between Vertebrates and Invertebrates Vertebrates Invertebrates 1. Vertebrates have a backbone or spinal 1. Invertebrates dont have backbone. column, have an internal skeleton made of bone 2. Invertebrates dont have cell walls 2. They have outer covering of protective 3. Examples of invertebrates are insects, cellular skin flatworms, flies 3. Examples of vertebrates are human, gorillas, monkeys, kangaroo, birds, 4. Invertebrates tend to be small and slow crocodiles, dolphins, mammals moving. 4. mostly bigger than the invertebrates and faster 5. 98% are invertebrates 5. 2% of animal species are vertebrates 6. Invertebrates have radial or bilateral symmetry 6. Vertebrates have only bilateral symmetry 4