Reproduction and Development

• Organismal Biology - Study of structure, function, ecology and evolution at the level of the organism.
• Biological Processes - These are vital for survival and interactions of organisms and the environment.
• Reproduction - Also called procreation or breeding. Biological process by which new individual organisms, offspring are produced from their parent/s.
• Asexual Reproduction - An organism can reproduce without the involvement of another organism. It is not limited to single-celled organisms. The cloning of an organism is a form of this reproduction. By this reproduction, an organism creates a genetically similar or identical copy of itself. This has four types of, namely: fission, fragmentation, budding, and sporulation.
• Fission - Division of a body into two or more equal parts. Example: Paramecium Caudatum
• Binary Fission - Two daughter cells are formed from a single parent. Example: Prokaryotic Bacteria
• Multiple Fission - Many daughter cells are produced from the parent cell. Example: Algae
• Fragmentation - Body breaks into two or more parts, and each fragment can develop into a complete individual. It is usually followed by regeneration to produce the missing parts. Example: Spirogyra
• Budding - An outgrowth or bud from its parent, arises and develops organs like those the parent, then detaches to become a new individual. Example: Hydra
• Sporulation - During unfavorable conditions, a bacteria can form an endosphere, a dormant cell will preserved DNA, in a process called sporulation. It can stay dormant for a long time before germinating. Endospores are present in vaccines. Example: Rhizopus Microsporus (fungus)
• Sexual Reproduction - An organism can reproduce with the involvement of another organism. This reproduction, organisms create genetically hybrid offspring. This has four types, namely: isogamy, heterogamy/anisogamy, and hermaphroditism
• Isogamy - Some gametes have similar morphology and are unusually both motile. Fertilization occurs due to slight variation in alleles, with mating types, either (+) or (-). Examples: fungi, algae, and protozoa.
• Conjugation - Two filamentous gametes line side-by-side, and one side will grow projections to form a bridge and allow fusion of protoplasts. This forms zygospore that can germinate under good conditions.
• Heterogamy/Anisogamy - Fusion of two gametes with different sizes or forms.
• Oogamy - Union of a large immotile egg and a small motile sperm. Example: Human
• Hermaphroditism - A hermaphrodite is an individual having both a male and a female reproductive organs. Hence, self-fertilization occurs. Some fishes are hermaphrodites, but hermaphroditic worms have means to avoid self-fertilization.
• External Fertilization - Usually occurs in aquatic environment where both eggs and sperm are released into the water which is called spawning. Examples: Nearly in all fish, crustaceans (crabs and shrimp), mollusks (oysters and squid), and echinoderms (sea oysters and sea cucumbers)
• Internal Fertilization - Occurs most often in land-based animals, although some aquatic animals also use this method. This has three ways of producing offspring, namely: oviparity, ovoviviparity, and viviparity.
• Oviparity - Fertilized egg are laid outside the female's body and develop there, receiving nourishment from the yolk that is part of the egg. Reptiles and insects produces leathery eggs, while birds and turtles produces eggs with high concentration of calcium carbonate in the shell, making them hard. Examples: Most bony fish, many reptiles, some cartilaginous fish, most amphibians, two mammals, and all birds
• Ovoviviparity - Fertilized egg are retained in the female, but the embryo obtains its nourishment from the egg's yolk; the young are fully developed when they are hatched. Examples: Fish (guppy and lebistes reticulatus), some sharks, some lizards, some snakes (garter snake and thamnopis sirtails), some vipers, and some invertebrate animals (madagascar hissing cockroach and gromphadorina portentosa)
• Viviparity - Young develop within the female, receiving nourishment from the mother's blood through placenta, and is born alive. Examples: Most mammals, some cartilaginous fish, and a few reptiles
• Developmental Biology - Study of growth and development of plants and animals.