BIO G11 Unit 2: Animals PDF

Unit 2: Animals --- 2.1 Characteristics of Animals Overview - Eukaryotic and Multicellular: Animals have complex cell structures and are made up of many cells. - Heterotrophic Nutrition: Animals cannot produce their own food and rely on consuming other organ...

Unit 2: Animals --- 2.1 Characteristics of Animals Overview - Eukaryotic and Multicellular: Animals have complex cell structures and are made up of many cells. - Heterotrophic Nutrition: Animals cannot produce their own food and rely on consuming other organisms. - Motility: Most animals can move, either during their entire life or at some stage. - Sensitivity: Animals can respond to stimuli due to their nervous system. Animals can be classified into two main categories: vertebrates and invertebrates. --- 2.2 Invertebrates and Vertebrates Invertebrate Animals - Characteristics: Lack a backbone or vertebral column, may have an exoskeleton (e.g., insects). - Examples: Earthworms, insects, jellyfish, snails, and crabs. Vertebrate Animals - Characteristics: Have a backbone, a more complex organ system, and an internal skeleton. - Examples: Mammals, birds, fish, reptiles, and amphibians. - Cold-blooded (poikilothermic): Fish, reptiles, amphibians. - Warm-blooded (homeothermic): Mammals and birds. --- 2.3 Reproduction in Animals Types of Reproduction - Asexual Reproduction: Common in invertebrates, involves a single parent (e.g., budding, fragmentation, parthenogenesis). - Sexual Reproduction: Involves two parents and the fusion of male and female gametes. Fertilization can be internal or external. Reproduction in Specific Animals a) Insects: Can reproduce through complete or incomplete metamorphosis. b) Frogs: Exhibit external fertilization, undergoing metamorphosis from egg to tadpole to adult. c) Crocodiles: Practice internal fertilization and lay hard-shelled eggs. d) Birds: Engage in internal fertilization, laying eggs with a hard shell; display parental care through incubation and feeding. e) Rats: Represent mammalian reproduction with internal fertilization, live birth, and significant parental care. --- 2.4 Economic Importance of Animals (Insects) Beneficial Aspects - Pollination: Insects like bees are vital for pollinating crops, contributing to food production. - Decomposers: Break down organic matter, recycling nutrients in ecosystems. - Industrial Uses: Insects produce valuable substances like silk, honey, and dyes. Harmful Aspects - Pests: Insects such as locusts and termites can damage crops, stored food, and property. - Disease Vectors: Some insects transmit diseases to humans, animals, and plants (e.g., mosquitoes spreading malaria). --- Summary of Key Learnings - Animal Diversity: Animals display a wide range of characteristics, from simple invertebrates to complex vertebrates. - Reproduction: Varies across species, with adaptations for asexual and sexual reproduction. - Economic Significance: Insects play a critical role in agriculture, industry, and health, with both beneficial and harmful impacts. --- ---