Biology: Reproduction and Life Cycle

Reproduction

• Reproduction is the process that secures continuation of life forms on earth.
• In plants, fertilization typically involves the fusion of two gametes within the ovule.
• In animals, fertilization generally occurs within the female reproductive tract.
• Sexual reproduction in both plants and animals requires the fusion of gametes.
• Double fertilization can cause formation of a zygote and endosperm.

Nutrition

• Autotrophic nutrition in plants is more energy-efficient and resource-utilizing compared to heterotrophic nutrition in animals.
• Plants directly convert sunlight into usable energy through photosynthesis.
• Mycorrhizae originates from fungal symbiosis, whereas root nodules result from bacterial symbiosis.

Digestive System

• The digestive tract is commonly arranged in mouth, esophagus, stomach, small intestine, large intestine, rectum, and anus.

Respiration

• Pulmonary circulation involves the pumping of deoxygenated blood from the heart to the lungs for oxygenation and then returning to the heart as oxygenated blood.
• Lungs receive deoxygenated blood from the heart and return oxygenated blood.
• All gases exchanged between air and blood in mammals occur across the walls of alveoli.

Circulatory System

• Xylem transports water and minerals upward from roots to leaves.
• Phloem transports organic nutrients, such as sugars, bidirectionally between source and sink cells.
• Blood flows in pulmonary circulation happen between the heart and the lungs, while systematic circulation sends oxygenated blood out to the cells.

Nervous System

• The human nervous system is capable of a wide range of functions, and neurons are the basic unit of the nervous system.
• Central nervous systems refer only to the brain and spinal cord.
• Nervous systems do not produce hormones and distribute them to the receptors.

Hormones

• Hormones in plants regulate biochemical and physiological responses.
• Consuming sweets can increase the hormone insulin.
• Excess number of hormones secreted by glands can lead to disorders related to the endocrine system.

Excretory System

• The human excretory system is designed in order (kidney, ureter, urinary bladder, and urethra).
• Nitrogenous waste is removed by the kidney in the human body.
• Build-up of toxins in the bloodstream can occur if there is no disposal of metabolic wastes.

Immunity

• The primary similarity between plant immunity and the innate immune system of animals is that they both recognize and respond to pathogens using innate mechanisms.
• Innate immune response provides immediate protection against a wide range of pathogens.
• Humans infected with a bacterial infection secrete antibodies or immunoglobulins to neutralize and mark the bacteria for destruction.

Homeostasis

• Homeostasis is the maintenance of stable internal conditions within an organism.
• The chemical and nervous control in our body maintains homeostasis in our body.