General Biology II Notes PDF

GENERAL BIOLOGY II Notes Life Processes Organ Systems Acquire materials and energy Digestive System (food) Muscular System...

GENERAL BIOLOGY II Notes Life Processes Organ Systems Acquire materials and energy Digestive System (food) Muscular System Skeletal System Coordinate Body Activities Endocrine System Nervous System Eliminate Wastes Digestive System Urinary System Exchange gases Respiratory System Maintain Body Shape Muscular System Skeletal System Produce Offspring Reproductive System Protect the body from pathogens Immune System Lympathic System Transport Materials Cardiovascular System Chemicals called “Hormones” regulate many aspects of plant growth, flower, and fruit development, senescence and responses to environment changes. A hormone is a biochemical synthesized in small quantities in one part of the organism and transported to another location where it stimulates or inhibits a response from target cells. PLANT HORMONES CLASSIC FIVE Plant Hormone Site/s of Mode of Selected Actions Synthesis Transport Inhibits shoot growth and maintains bud Mature leaves dormancy especially in In xylem and Abscisic Acid plants under Phloem Induces and drought or maintains seed freezing stress dormancy Stimulates closure of stomata Promotes leaf, flower and fruit abscission Stimulates Shoot apical Diffusion elongation of cells Auxins meristem, between in stem developing leaves parenchyma cells and fruits with vascular Controls tissue phototrophisms,  gravitophism, and thigmotropism Suppresses growth of lateral buds Stimulates cell division in seeds, roots, young Root Apical In xylem leaves, and fruits Cytokinin Meristem Delays leaves senescence Stimulates growth in lateral buds Hastens fruit ripening All parts especially under Diffusion of Gas Stimulates leaf Ethylene stress, aging or and flower ripening senescence Stimulates leaf and fruit abscission Participates in thigmotropism Gibberellin Young shoot, In xylem and Stimulates cell developing seeds phloem division and elongation in roots, shoots, and young leaves Breaks seed dormancy PLANT REPRODUCTION VS. ANIMAL REPRODUCTION Reproduction is the biological process by which new individual organisms— “offspring”—are reproduced from their parents. Reproduction is a fundamental feature of all known life; each individual organism exists as a result of reproduction. Feature Plants Animals Behavior Displayed Uses bright colors to Males thinging for attract insects females (inclusive fitness) Ophyrys Kotschyi mimics the shape of a Courtship pheromones bee to attract insects and ultrasound are  used by males in attracting female Method of Fertilization Sex cells are Two sex cells transmitted by a vector spermatozoa and oocyte (bird or insect) meet during sexual intercourse Method of Asexual Reproduction Asexual Reproduction Reproduction does not involve gametes Sexual Reproduction Sexual reproduction use of male and female gamete forming a zygote PLANT REPRODUCTION Plants have reproductive structures called Flowers. Plants reproduce sexually through Pollination—refers to the transfer of pollen from the anther to the stigma of the same flower or another flower. It comes in two forms: self-pollination and cross-pollination. Self-pollination occurs when pollen from another is deposited on the stigma of the same flower, or anther flower on the same plant. Cross-pollination is the transfer of pollen from one anther of one flower to the stigma of anther flower of the same species. Pollination is possible through various agents like birds, insects, and wind. Plants can also reproduce asexually. It means that plants can propagate even without the union of gametes. The two main types of asexual reproduction in plants are Vegetative propagation and Apomixes. Vegetative Propagation—means that vegetative tissues (non-reproductive tissues) such as stem, leaf or root of the parent plant are used to reproduce new plants. Natural vegetative propagation includes stolon or runner, bulb, rhizome, tuber, corn, and sucker. SEXUAL AND ASEXUAL REPRODUCTION Both plants and animals can reproduce sexually involving male and female gametes. However, only plants can reproduce asexually (e.g., budding, fragmentation, vegetative propagation). Animals cannot reproduce asexually. The terminal portion of the female reproductive organ serves as the site for sperm entry during reproduction. During copulation, sperm from the male reproductive organ is deposited into the female reproductive tract, where it travels to meet the egg for potential fertilization. Other functions of the female reproductive system include the release of eggs during ovulation, which is carried out by the ovaries. The ovaries also play a role in producing female sex hormones. While some animals can store sperm for later fertilization, this is not a function of the human female reproductive system. The nervous system (brain, spinal cord, and nerves) regulates body activities using electrical signals. The endocrine system (glands like the hypothalamus, pituitary, and thyroid) controls body functions through hormones. Both systems work together to maintain homeostasis by adjusting body responses to internal and external changes. Parasympathetic nervous system controls the "rest and digest" functions, promoting relaxation and energy conservation. The sympathetic nervous system is responsible for triggering the "fight or flight" response, which prepares the body for emergency situations. When activated, it increases heart rate, dilates pupils, redirects blood flow to muscles, and releases adrenaline to enhance alertness and reaction speed. Somatic nervous system controls voluntary movements of skeletal muscles. Autonomic nervous system controls involuntary bodily functions. Animals react quickly to external stimuli using rapid electrical impulses transmitted by the nervous system (sensory and motor neurons) while Plants respond slowly to stimuli like light through phototropism (growth toward or away from light, regulated by hormones like auxins). Unlike animals, plants do not have a nervous system or electrical impulses for fast responses. Chemoreceptors are responsible for detecting chemical stimuli, such as taste and smell, rather than gravity. Gravity is sensed by mechanoreceptors in specialized structures like the vestibular system in animals. Mechanoreceptors detect touch and pressure (e.g., in the skin). Electroreceptors detect energy (common in some aquatic animals like sharks). Photoreceptors detect light (found in eyes and responsible for vision). The hypothalamus plays a central role in regulating homeostasis and body temperature. It maintains balance in the body by controlling functions such as thirst, hunger, sleep, and hormone release. It also communicates with the endocrine system to regulate body temperature by triggering responses like sweating or shivering. Cerebrum controls higher cognitive functions like thinking and memory. Cerebellum coordinates movement and balance. Medulla Oblongata regulates involuntary functions like heart rate and breathing but does not directly control body temperature. Homeostasis refers to the body's ability to maintain a stable internal environment despite external changes. It regulates factors such as body temperature, blood pH, and fluid balance to ensure that the body's systems function properly. Metabolism, on the other hand, involves the chemical processes that convert food into energy. Circulation is responsible for blood flow and the transport of nutrients and oxygen, while digestion refers to the breakdown of food into nutrients. Among these options, only homeostasis ensures that the body remains in balance for survival.