Class 12 Zoology Application of Zoology Notes

Unit 10

Applied Biology

Chapter 10.1

Application of Zoology

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Introduction

Definition Applied zoology is the practical application of zoological knowledge and biological techniques for human welfare, medicine, agriculture, animal production and related fields.

In Grade 12 Biology, this chapter focuses on tissue and organ transplantation, in-vitro fertilization (IVF), amniocentesis, genetically modified or transgenic animals, poultry farming and fish farming.

1. Tissue and Organ Transplantation

Definition Transplantation is the transfer of cells, tissues or organs from one site or individual to another to replace damaged or non-functional biological structures.

Types of Grafts

TypeSource and RecipientExample
AutograftTissue transferred within the same individual.Skin graft from one body region to another.
IsograftBetween genetically identical individuals.Transplant between identical twins.
AllograftBetween genetically different individuals of the same species.Human kidney transplant.
XenograftBetween different species.Use of animal-derived biological tissue in humans.

Fig. 1 – Major Types of Transplantation

Transplantation Autograftsame person Isograftgenetically identical Allograftsame species Xenograftdifferent species

Transplant Rejection

The recipient immune system may recognize donor antigens as foreign and attack the transplanted tissue. Matching donor and recipient characteristics and carefully managed immunosuppressive treatment help reduce rejection risk.

ExamplesKidney, liver, heart, cornea, skin and bone marrow are among the tissues or organs that may be transplanted in appropriate medical settings.

2. In-Vitro Fertilization (IVF)

Definition In-vitro fertilization is an assisted reproductive technique in which fertilization of an egg by sperm occurs outside the body under laboratory conditions, followed by transfer of a developing embryo into the uterus.

General Steps of IVF

  1. Controlled stimulation of ovaries so that suitable oocytes develop.
  2. Collection of mature oocytes.
  3. Collection and preparation of sperm.
  4. Fertilization in the laboratory.
  5. Culture of the resulting embryo for a short period.
  6. Transfer of selected embryo(s) into the uterus.
  7. Follow-up to determine whether implantation and pregnancy occur.

Fig. 2 – Basic Steps of IVF

Ovarianstimulation Oocytecollection Laboratoryfertilization Embryoculture Embryotransfer Fertilization occurs outside the body; embryo is later transferred to the uterus.

3. Amniocentesis

Definition Amniocentesis is a prenatal diagnostic procedure in which a small sample of amniotic fluid is withdrawn under medical guidance for laboratory examination.

The fluid contains fetal cells and biochemical substances that can provide information about selected chromosomal or genetic conditions when clinically indicated.

Fig. 3 – Simplified Amniocentesis

Needle enters amniotic sac under imaging guidance Amniotic fluidFetus
ImportantAmniocentesis is a medical procedure performed only by trained healthcare professionals for appropriate clinical reasons. It has potential risks and is not a routine do-it-yourself test.

4. Genetically Modified Organisms and Transgenic Animals

Definition A transgenic animal is an animal whose genome has been deliberately modified so that introduced genetic material is stably present and may be expressed.

General Concept

  1. A gene or genetic construct of interest is selected.
  2. It is introduced into cells or an early embryo using an appropriate genetic technique.
  3. Modified cells or embryos are selected and developed.
  4. Animals carrying the intended genetic change are identified.
  5. The trait or gene expression is studied or used for a defined purpose.

Fig. 4 – Concept of a Transgenic Animal

Gene ofinterest Introduction intoembryo / cells Developinganimal Transgenicanimal

Applications

  • Study of gene function and disease mechanisms.
  • Development of biological products.
  • Testing of potential therapeutic approaches in research.
  • Improvement of selected livestock traits in controlled breeding programs.
EthicsGenetic modification of animals raises animal-welfare, ecological, biosafety and ethical questions and therefore requires regulation and oversight.

5. Poultry Farming

Definition Poultry farming is the scientific rearing and management of domesticated birds for products such as eggs and meat.

Major Production Types

Layer Farming

Birds are managed mainly for egg production.

Broiler Farming

Birds are raised mainly for meat production.

Important Management Factors

  • Selection of healthy and suitable breeds.
  • Balanced feed and clean drinking water.
  • Proper housing, ventilation, temperature and litter management.
  • Biosecurity and disease prevention.
  • Vaccination according to veterinary guidance.
  • Clean handling of eggs and poultry products.

Fig. 5 – Poultry Farming Management Cycle

Healthychicks Housing &sanitation Feed &water Health &biosecurity Good management improves productivity, welfare and disease control.

6. Fish Farming

Definition Fish farming or pisciculture is the controlled breeding, rearing and harvesting of fish for food, stocking or commercial production.

Basic Pond Types in Fish Farming

PondGeneral Purpose
Nursery pondRearing very young fry during early stages.
Rearing pondGrowing fry into larger fingerlings.
Stocking / grow-out pondGrowing fingerlings to harvestable size.

Fig. 6 – Simple Fish-Farming Pond System

Water inletOutlet Managed pond: suitable water quality, stocking density, feed and disease control

Major Management Principles

  • Choose appropriate fish species and healthy seed/fingerlings.
  • Maintain suitable pond depth, water quality and oxygen conditions.
  • Provide suitable natural or supplementary feed.
  • Prevent predators, escape and disease spread.
  • Use proper stocking density and monitor growth.
  • Harvest at appropriate size and handle fish hygienically.

Induced Breeding – Basic Concept

In hatchery practice, reproductive maturation and spawning can be managed under controlled conditions. Brood fish are selected, spawning is induced when appropriate, eggs are fertilized, and hatchlings are reared before transfer to nursery and grow-out systems.

Fig. 7 – Fish Seed Production Flow

Brood fishselection Spawning /fertilization Eggs &hatching Fry /nursery Fingerlingsgrow-out

7. Quick Revision & Exam Points

Important Questions
  • Define transplantation and explain the main types of grafts.
  • What is transplant rejection?
  • Define IVF and explain its main steps.
  • Define amniocentesis and state its purpose.
  • What is a transgenic animal?
  • Write applications and ethical issues of transgenic animals.
  • Differentiate layer and broiler poultry farming.
  • Write important management practices in poultry farming.
  • Define fish farming and explain the major pond types.
  • Describe the general process of fish seed production or induced breeding.

One-Minute Revision

  • Autograft = same individual.
  • Isograft = genetically identical individuals.
  • Allograft = different individuals of same species.
  • Xenograft = different species.
  • IVF = fertilization outside the body.
  • Amniocentesis = prenatal sampling of amniotic fluid.
  • Transgenic animals contain introduced genetic material.
  • Layers are reared mainly for eggs.
  • Broilers are reared mainly for meat.
  • Pisciculture = controlled fish farming.
  • Nursery → rearing → grow-out is a common pond sequence.
Diagram Practice Practice the transplantation-types chart, IVF flow, amniocentesis, transgenic-animal concept, poultry-management flow and fish-farming diagrams.

Source note: Nepal eNotes identifies this material as Unit 10, Applied Biology, Chapter 10.1, Application of Zoology. Its current page exposes a “PDF Link: View” control but the hidden Drive target was not available to automated extraction, so no Drive ID has been invented here. The typed notes follow the verified Grade 12 syllabus scope for this chapter.

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