Organismal Biology Lesson Notes PDF

LESSON 1: ORGANISMAL BIOLOGY Objective: Compare and contrast the following processes in plants and animals: reproduction, development, nutrition, gas exchange, transport/circulation, regulation of body fluids, chemical and nervous control, immune systems, and sensory and motor mechanisms. Basis...

LESSON 1: ORGANISMAL BIOLOGY Objective: Compare and contrast the following processes in plants and animals: reproduction, development, nutrition, gas exchange, transport/circulation, regulation of body fluids, chemical and nervous control, immune systems, and sensory and motor mechanisms. Basis for Plants Animals Comparison Plants can reproduce either sexual or asexual reproduction. Some lower animals reproduce asexually through parthenogenesis (a form of reproduction in which an egg can develop into an embryo without being fertilized Flowering plants reproduce sexually through a process called pollination by a sperm), budding (small growth on surface of parent breaks off, resulting in (the transfer of pollen from flower-to-flower in angiosperms or cone-to- the formation of two individuals.), fragmentation (organisms break into two or more cone in gymnosperms, takes place through self-pollination or cross- fragments that develop into a new individual), or binary fission (single parent cell pollination). The flowers contain male sex organs called stamens and doubles its DNA, then divides into two cells, usually occurs in bacteria). female sex organs called pistils. While higher animals reproduce sexually through fertilization (the fusion of haploid Asexual reproduction includes vegetative propagation (new individuals gametes, egg and sperm, to form the diploid zygote) and give birth to the young 1. Reproduction are made without seeds or spores), fragmentation (part of the body being ones. divided. Ex: liverworts and mosses); and; budding (parent organism produces offspring by growing a tiny replica of itself). In vegetative propagation, example are: true bulb (underground shoots with modified leaves. Ex: onions, garlic), tubers (form buds which make new plants underground. Ex: potato), rhizomes (like runners but underground. Ex: ginger), and stolons (plant stems send out extensions above ground. Ex: strawberries). Fragmentation is another form of asexual reproduction that involves new plants growing from small parts of the parent plant that fall to the ground. The growth of the plant is not restricted and takes place through life in Animals are confined to grow up to the certain period and their organs and organ 2. Growth / their meristematic regions like roots, stems, tips of leaves, etc. system support the growth. Development  Plants are known as autotrophs. They have chlorophyll, due to which Animals are known as heterotrophs (organisms that cannot make their own food 3. Mode of they have the capability to prepare their own food in the presence of air, and obtain their energy from other organisms). They depend on plants for their Nutrition water and sunlight. food. 4. Gas Plants take in carbon dioxide and release oxygen into the atmosphere, Animals take in oxygen and release carbon dioxide into the atmosphere, which Exchange exchange of gases occurs through stomata. occurs through lungs, gills, skin, etc. Plants are less complex and requires less food and water to survive Animals are more complex creatures and require more food and nutrients because compared to animals. they are able to move about. An animal's circulatory system is the main transport system in the body and is one of the keys that make all other bodily functions A plant takes in water and dissolved nutrients from the soil via roots. The possible. An animal's circulatory system consists of the heart, blood vessels -- xylem is the specialized plant tissue that is responsible for carrying water arteries, veins, and capillaries -- and the blood. and dissolved minerals taken in from the roots. 5. Transport / The heart is the pump that pushes the blood to move along the arteries and veins. Circulation Another structure is the phloem, which is responsible for translocation or Blood from the heart and lungs usually passes through the arteries and carries the process of transporting food from the leaves into different parts of with it oxygen and nutrients to be distributed into the many organs and cells via the plant. The phloem is positioned just outside the xylem. smaller blood vessels called the capillaries. After distribution of these nutrients, the blood goes into the veins and takes with it waste products, like carbon dioxide and other chemical wastes, to be eliminated via the organs responsible for proper waste excretion. Higher plants use the stomata on the underside of leaves to control water Animals utilize an excretory system to control the amount of water that is lost to loss. Plant cells rely on vacuoles to regulate cytoplasm osmolarity. the environment and maintain osmotic pressure. Protein metabolism also Plants that live in hydrated soil (mesophytes) easily compensate for generates waste molecules which could disrupt osmotic pressure. The organs that water lost from transpiration by absorbing more water. The leaves and are responsible for osmoregulation depend on the species. 6. Regulation of stem of the plants may be protected from excessive water loss by a waxy Body Fluids outer coating called the cuticle. Marine invertebrates with body fluids that are generally hyperosmotic to their surroundings are called osmoconformers because they allow the osmolarity of Plants that live in dry habitats (xerophytes) store water in vacuoles, have their body fluids to match that of the environment. Marine vertebrates, birds and thick cuticles, and may have structural modifications (i.e., needle-shaped mammals, on the other hand are osmoregulators, because they keep the leaves, protected stomata) to protect against water loss. osmolarity of body fluids different from their environment.  Plants that live in salty environments (halophytes) have to regulate not only water intake/loss but also the effect on osmotic pressure by salt. Some species store salts in their roots so the low water potential will draw the solvent in via osmosis. Salt may be excreted onto leaves to trap water molecules for absorption by leaf cells. Plants that live in water or damp environments (hydrophytes) can absorb water across their entire surface. A plant’s sensory response to external stimuli relies on chemical Vertebrates have ductless glands/ Endocrine glands that produces hormones. messengers (hormones). Plant hormones affect all aspects of plant life, from flowering to fruit setting and maturation, and from phototropism to Hormones are chemical messengers secreted by a gland and affect the specific leaf fall. Just as in animals, hormones are signaling molecules which are target tissue or organ. The Endocrine and nervous system coordinate with each present in very small amounts, transported throughout the plant body, other through a series of feedback mechanism. Feedback mechanism is a and only elicit in responses in cells which have the appropriate hormone mechanism or a signal that tends to initiate (or accelerate) or to inhibit (or slow receptors. In plants, hormones travel large throughout the body via the down) a process. vascular tissue (xylem and phloem) and cell-to-cell via plasmodesmata. Potentially every cell in a plant can produce plant hormones. Here are some of the Endocrine glands and hormones they produced. a) Hypothalamus - the hormones from the hypothalamus govern physiologic 7. Chemical Some of these plant hormones are: functions such as temperature regulation, thirst, hunger, sleep, mood, sex drive, and Nervous a) Auxin - the master growth regulator; and the release of other hormones within the body; Control b) Cytokinin - which is responsible for cell division; b) Anterior Pituitary gland - Growth Hormone (GH), stimulates growth, c) Gibberellins - responsible for stem, fruit, and seed growth; Adrenocorticotropic hormone (ACTH), regulates levels of the steroid hormone d) Abscisic Acid (ABA) - that causes dormancy of the plant; cortisol, which released from the adrenal gland; e) Ethylene - promotes fruit ripening, flower wilting, and leaf fall; c) Parathyroid gland- secretes Parathyroid Hormone, increases blood 𝑪𝒂 𝟐+; f) Systemin - anti-herbivory hormone that activates plant responses to d) Thyroid gland – produces thyroxine that increases metabolic rate and heart rate; wounds from herbivores; promotes growth; g) Methyl Salicylate (MeSa) - hormone for immunity that helps regulate e) Adrenal glands – Epinephrine, produces many effects related to short-term responses to infection by parasites or pathogens stress response, Cortisol, produces many effects related to short-term and long- term responses, Aldosterone, increases reabsorption of 𝑁𝑎+ by kidneys; f) Pancreas - Islets of Langerhans Insulin, decreases blood glucose, Glucagon, increases blood glucose Kidneys, Erythropoietin (EPO), increases synthesis of red blood cells Vitamin D and decreases blood 𝐶𝑎2+;  g) Ovaries – Estradiol, regulates development and maintenance of secondary sex characteristics in females; other effects; Progesterone- prepares uterus for pregnancy; h) Testes – testosterone, regulates development and maintenance of secondary sex characteristics in males; other effects. All animals have a true nervous system except sea sponges. Cnidarians, such as jellyfish, lack a true brain but have a system of separate but connected neurons called a nerve net. Echinoderms, such as sea stars, have neurons that are bundled into fibers called nerves. Flatworms of the phylum Platyhelminthes have both a CNS made up of a small brain and two nerve cords, and PNS containing a system of nerves that extend throughout the body. Cephalopods, such as octopus, may have the most complicated of invertebrate nervous systems, with neurons that are organized in specialized lobes and eyes that are structurally similar to vertebrate species. Compared to invertebrates, vertebrate nervous systems are more complex, centralized, and specialized. While there is great diversity among different vertebrate nervous systems, they all share a basic structure: a CNS that contains a brain and spinal cord and a PNS made up of peripheral sensory and motor nerves. One interesting difference between the nervous systems of invertebrates and vertebrates is that the nerve cords of many invertebrates are located ventrally (along the belly) whereas the vertebrate spinal cords are located dorsally (along the back). Plants respond to infection using a two-branched innate immune system. Vertebrates have advanced protective system called the immune system. The The first branch recognizes and responds to molecules common to many immune system is a complex network of organs containing cells that recognize 8. Immune classes of microbes, including non-pathogens. The second responds to foreign substances in the body and destroy them. It protects vertebrates against Systems pathogen virulence factors, either directly or through their effects on host pathogens, or infectious agents, such as viruses, bacteria, fungi, and other targets. These plant immune systems, and the pathogen molecules to parasites. The human immune system is the most complex. which they respond, provide extraordinary insights into molecular recognition, cell biology and evolution across biological kingdoms. The Two Subsystems:  Methyl Salicylate (MeSa) is a hormone for plant immunity that helps 1. Innate immune system: nonspecific in aiming pathogens. It consist of 1st , 2nd , regulate responses to infection by parasites or pathogens. and 3rd line of defenses. 2. Adaptive immune system: specific in aiming pathogens. All living things respond to environmental stimuli primarily to survive. They have proper nervous system and response to any stimuli in a fraction of Plants, which are sessile exhibit responses to stimuli such as light, water, seconds, so they are regarded as highly sensitive. touch and wind. Responses are important to get a needed nutrient, survive a certain condition or defend itself from predators and to There are five sensory receptors: a) photoreceptors, responds to light; b) reproduce. Tropism, a biological mechanism that enables plant to move Mechanoreceptors, respond to physical stimuli such as sound or touch; c) toward (positive tropism) or against (negative tropism) the source of a Chemoreceptors, detect chemicals; d) Thermoreceptors, respond to temperature; 9. Sensory and stimulus. Examples are: Geotropism, gravity causes a response in a e) pain receptors, detect possible tissue damage. Motor plant’s growth; hydrotropism, the way plants grows or bends in response Mechanisms to water; thigmotropism, plants bend or grow because of touch; Animals can move from one place to another freely, and exceptions are Sponges phototropism; the way plant grows or bends in response to light. and Corals. Plants do not have the ability to move from one place to another, as plants are rooted into the ground, exceptions are Volvox and Chlamydomonas. References: https://pubmed.ncbi.nlm.nih.gov/17108957/#:~:text=Many%20plant%2Dassociated%20microbes%20are,microbes%2C%20including%20non%2Dpathogens. https://www.aber.ac.uk/~dcswww/ISYS/immune_system.html https://www.sciencedirect.com/topics/agriculturalandbiologicalsciences/parthenogenesis#:~:text=Parthenogenesis%20is%20a%20form%20of,known%20to%20reproduce%20by %20parthenogenesis.