L3 Plant & Animal Development

• Plants have a unique life cycle that involves alternation between two distinct generations: the sporophyte and the gametophyte.
• Sporophyte Generation: is the dominant phase in most plants and is responsible for producing spores through meiosis.
• These spores develop into the Gametophyte generation, which produces gametes through mitosis.
• The fusion of gametes leads to the formation of a new sporophyte, completing the life cycle.
• Seed Development: In flowering plants, the development starts with the formation of a seed.
• Seed Development: The seed contains an embryo, which is the young plant, along with a food source and a protective seed coat.
• Seed Development: begins with pollination, where pollen grains are transferred from the male reproductive organ (stamen) to the female reproductive organ (pistil).
• Seed Development: Fertilization occurs when the pollen tube delivers sperm cells to the ovule, resulting in the formation of a zygote.
• Seed Development: The zygote then develops into an embryo, which eventually becomes a seed.
• Plant Development: Seed Development & Germination and Growth
• Germination and Growth: When conditions are favorable, the seed undergoes this, which is the process of the embryo growing and emerging from the seed coat.
• Germination and Growth: triggered factors such as water, temperature, and light
• Germination and Growth: Once the seed germinates, the embryo develops into a seedling, which grows into a mature plant through cell division and elongation.
• Germination and Growth: Plant growth occurs primarily at the tips of roots and shoots, where specialized cells called meristems continuously divide and differentiate into various tissues.
• Animal Development: do not have a distinct alternation of generations.
• Plant Development: involves alternation between two distinct generations: the sporophyte and the gametophyte.
• Animal Development: involves the growth and differentiation of cells and tissues to form complex body structures.
• Animal Development can be categorized into three stages: fertilization, embryonic development, and post-embryonic development
• Fertilization (Animals): occurs when a sperm cell fuses with an egg cell, resulting in the formation of a zygote.
• Fertilization (Animals): can happen internally or externally, depending on the species
• Fertilization: In some animals, fertilization is followed by the formation of a protective structure, such as an eggshell or amniotic sac, to support embryonic development.
• Embryonic Development: During this, the zygote undergoes a series of cell divisions and differentiations to form a multicellular embryo.
• Embryonic Development: This process involves the formation of germ layers, which give rise to different tissues and organs in the body.
• Embryonic Development: The three primary germ layers in animals are the ectoderm (outer layer), mesoderm (middle layer), and endoderm (inner layer).
• Embryonic Development (cont.): These layers develop into various structures, such as the nervous system, muscles, and digestive system.
• Post-embryonic Development: After the completion of embryonic development, animals continue to grow and mature through this.
• Post-embryonic Development: This stage involves further growth, organ formation, and functional specialization.
• Post-embryonic Development: during this, animals may undergo metamorphosis, a dramatic transformation in body structure.
• Post-embryonic Development: Examples of metamorphosis include the transformation of a tadpole into a frog or a caterpillar into a butterfly.
• Seed vs. Egg: Plants develop from seeds, which contain an embryo and a food source. Animals, on the other hand, develop from eggs, which also contain an embryo but may have additional protective structures.
• Alternation of Generations: Plants exhibit an alternation of generations, with the sporophyte and gametophyte generations. Animals do not have this alternation and instead have a continuous life cycle.
• Growth Patterns: Plant growth occurs primarily at the tips of roots and shoots, while animal growth occurs through the growth and differentiation of cells and tissues throughout the body.
• Metamorphosis: Some animals, such as insects and amphibians, undergo metamorphosis during their development, which involves a significant change in body structure. Plants do not undergo metamorphosis.