Animal Reproduction

• Asexual reproduction - individuals are exact clones of the parent with

  identical genetic makeup.
• Sexual reproduction - new individuals are formed from the combination of haploid gametes to form genetically unique offspring.
• Reproduction is a process by which an organism may

  produce offspring and perpetuate it species. Organisms are

  able to pass on traits from one offspring to another and

  from one generation to another. Living things can produce

  new organisms of the same kind.
• Terrestrial organisms – directly take in oxygen from the atmosphere.
• Aquatic Organisms – obtain the supply as dissolved oxygen, which occur in minute amounts.
• REGENERATION involves the production and differentiation of new tissues to replace missing and damaged parts of the body.
• BUDDING involves forming a new individual from an outgrowth on

  the parent’s body.
• PARTHENOGENESIS involves an activated unfertilized egg that undergoes mitosis in the absence of cytokinesis.
• Fragmentation - breaking of the body into several pieces
• DIOECIOUS Organisms producing only sperm are male and those

  producing egg only are female.
• MONOECIOUS OR HERMAPHRODITES In some animals, both female and male reproductive organs occur within the same individual. Organisms can produce both sperm and eggs, they usually do not self-fertilize.
• PROTANDRY, an organism may start off male converting to

  female.
• PROTOGYNY, an organism may start off female converting to

  male.
• External Fertilization THE FEMALE RELEASES EGSS INTO THE ENVIRONMENT, WHERE THE MALE THEN FERTILIZES THEM
• A moist habitat is almost always required to prevent

  the gametes from drying out and to allow sperm to

  swim to the eggs.
• Internal Fertilization

  THE MALE DELIVERS SPERM CELLS DIRECTLY

  INTO THE BODY OF THE FEMALE.
• INDIRECT DEVELOPMENT involves one or more intermediate larval forms before the adult form is attained.
• Among animals that show indirect development, fertilization follows the random release of gametes in the environment.
• Any animal that deposits an egg in the external environment is oviparous.
• Oviparity - Fertilized eggs are laid outside the female’s body and develop there, nourishment from the yolk that is a part of the egg
• viviparity - give birth to young ones without laying eggs.