Plant Reproduction and Life Cycle

Reproduction

• Reproduction is a biological process where organisms produce offspring, ensuring the continuation of their species.
• The life cycle is a continuous sequence of stages, from conception to offspring production.

Plant Life Cycle

• Plant sexual life cycle involves diploid sporophytes and haploid gametophytes, alternating in generations.
• Flowers are reproductive structures in flowering plants, consisting of four whorls.

Stages in Plant Embryonic Development

• Plant embryonic development includes male and female gametophyte development.
• This also requires pollination, double fertilization, embryo development, ovule maturation, seed germination, and seedling growth.

Double Fertilization

• During double fertilization, the generative cell divides into two sperm cells as the tube cell transforms into a pollen tube.
• One sperm cell unites with the egg to form the zygote, while the other fuses with polar nuclei to create the endosperm, nourishing for the early embryo.
• Cotyledons store food, the radicle develops into the root, and the plumule develops into the shoot.
• Endosperm is responsible for nourishing the developing embryo.

Plant Nutrition

• Plants are autotrophic organisms, synthesizing food through photosynthesis.
• Autotrophic nutrition is plants is more energy-efficient compared to heterotrophic nutrition in animals.
• Substrate feeders live in their food source, filter-feeders strain food particles, fluid feeders extract nutrients, and bulk feeders eat large food pieces.

Animal Reproduction

• The testes produce sperm and testosterone, which are male sex hormones that influence body development.
• Ovaries produce eggs (ova) and female sex hormones like estrogen and progesterone.
• Fertilization occurs in the fallopian tube, where a sperm cell fertilizes an egg cell to form a zygote.
• All of this result in the formation of a unicellular zygote.

Parts of Digestive System

• Digestive system parts include the mouth, esophagus, stomach, small intestine, large intestine, rectum and anus.

Animal Nutrition

• Nutrition is attained through Carbohydrates, which are the source of energy
• Vitamins and trace minerals are also utilized to support vision
• Proteins are also required for growth and repair
• Fats are used for high-energy storage and essential amino acids are used for building muscles

Gas Exchange and Transport/Circulation in Plants and Animals

• Plants uptake molecular oxygen from the environment and discharge carbon dioxide in gas exchange.

Gas Exchange in Plants

• Gas exchange in plants is facilitated by the stomata in leaves, lenticels in stems, root hairs, and pneumatophores in mangroves.
• Leaves provide a large surface area for gas exchange in plants.

Gas Exchange in Animals

• Thin, vascularized epidermis projects from the body surface in amphibians during external respiration.
• Rows of slits or pockets in adult fishes, positioned at the back of the mouth facilitating the flow of water in internal respiration.
• Counter-current flow system maximizes gas exchange by having blood and water flow in opposite directions.

Lungs

• Lungs are internal respiratory surfaces shaped as a cavity or sac.
• They also require a circulatory system as they are not in direct contact with all other parts of the body.
• The lungs receive oxygen-poor blood to the heart, oxygenate it, and return oxygen-rich blood.
• Oxygen is required to extract ATP from food, and carbon dioxide released preventing tissues from becoming too acidic.

Breathing Mechanisms in Vertebrates

• Amphibians utilize positive pressure breathing that forces air down the trachea.
• Birds use air sacs to keep air flowing through the lungs in one direction, preventing the mixing of air.
• Mammals pull air into the lungs but mix incoming and outgoing air.

Pulmonary Circulation

• Deoxygenated blood is pumped from the heart to the lungs for oxygenation and then returned to the heart as oxygenated blood.

Plant Transport and Circulation

• The vascular tissue system carries materials between the root and shoot systems.
• Xylem conducts water and dissolved minerals upward.
• Phloem transports sugars bidirectionally between source and sink cells.

Human Circulatory System

• The human circulatory system delivers oxygen and nutrients to cells.
• Removal of carbon dioxide and waste materials also happens through the circulatory system.
• Arteries carry blood away from the heart, veins carry blood back, and capillaries allow exchange between blood and tissues
• Blood comprises of red blood cells that transport oxygen, white blood cells that fight infections, platelets that help with clotting and plasma, the liquid component.

The Routes and Function of Blood Flow

• Pulmonary circulation moves blood between the heart and lungs, transporting deoxygenated fluids to absorb oxygen and release carbon dioxide.
• Systemic circulation is the movement of blood between the heart and the rest of the body.

Nerves and Plant Responses

• Tropism are Plant's growth responses to stimuli like light, gravity, or touch.
• Hormones are chemical messengers that regulate different processes in plants.
• Nervous control uses electrical impulses for quick, short-term responses.

Control Systems

• Chemical control uses hormones for slower, long-term regulation through the endocrine system.
• The nervous and endocrine systems coordinate and interact through feedback mechanisms.
• Nervous system which transmits signals throughout the body, gathering info and send it to the brain.

Neuron

• The neuron is the basic structural and functional unit of the nervous system.
• The control nervous system (CNS) consists of the brain and spinal cord
• The peripheral nervous system (PNS) consists of nerves branching out from the brain and spinal cord to specific body parts.

Disorders

• Disorders may arise from under- or over-secretion of hormones.
• Sensory and motor mechanisms facilitate perception and appropriate motor responses.
• The 5 types of receptors include photoreceptors, mechanoreceptors, chemoreceptors, thermoreceptors and pain receptors.
• The Human ear is divided into outer, middle, and inner segments that detects sound and regulates balance.

Sense of Taste

• Taste perception is also influenced by olfactory receptors in the oral cavity, even without direct tasting.

Homeostasis in Plants and Animals

• Salt and water content regulation are crucial for all living things.
• The buildup of toxins can harm organs if the body fails to eliminate metabolic wastes.
• Transpiration is the process of water movement and evaporation

Role of Stomata

• plants utilize stomata to control water loss.
• The root cortex actively transports ions and minerals

Osmolarity

• Osmoconformers match body fluid osmolarity.
• Osmoregulators maintain internal osmolarity,

Kidneys

• Kidneys are excretory organs that remove nitrogenous wastes through the sequence in the human excretory system: Kidneys, Ureter, Urinary bladder and Urethra.

Defence Mechanisms

• Plant immunity defends against pathogens in cell-surface and intracellular immunity.
• The immune system is the body's is defense against disease by utilizing a vital network of cells and organs.

Innate Immunity

• Innate immunity is the first line of defense, providing immediate protection against pathogens
• Adaptive immunity builds up through exposure or vaccination, with humoral response-involving B cells and antibodies-, and cell-mediated response during the event of infection.

Homeostasis and Mechanisms

• Homeostasis is the maintenance of stable internal conditions.
• Receptors detect changes, control centers process the information for response and effectors produce a response.
• Negative feedback reverses change whereas a positive feedback amplifies the stimuli.