Lecture 2: Characters of Living Organisms PDF

Biology for Health Specialties Lecture (2) Characters of Living Organisms Lecture 2: Characters of Living Organisms, Biological Organization, Diversity of life. Dr. Abdelalim Gadallah Assistant Prof. of Embryology [email protected] Course Coordinator C...

Biology for Health Specialties Lecture (2) Characters of Living Organisms Lecture 2: Characters of Living Organisms, Biological Organization, Diversity of life. Dr. Abdelalim Gadallah Assistant Prof. of Embryology [email protected] Course Coordinator College of Science Biology Department (2nd Floor) Office No. 2621  Objectives After studying this lecture; the students should be able to: Define all definitions of biology-related terminology Differentiate between living and non-living things. Understanding levels of biological organization. Explain the scientific method and the diversity of organisms. Characters of living organisms Living organisms are characterized by many characteristics that distinguish them from non- living things such as: Organisms are composed of cells: All organisms are formed of basic structural and functional units called cells. According to the number of cells that form the body of an organism, organisms may be; unicellular or multicellular. ❑ Unicellular organisms consist of a single cell ex: Protozoa. ❑ Multicellular organisms consist of many cells (billions) ex: man. Growth: ❑ Means an increase in the size and number of cells. Development: It is the process that includes all changes during the life of an organism from a fertilized egg to an individual.  Unicellular Protozoa Regeneration https://byjus.com/biology/binary-fission/ https://bastiani.biology.utah.edu/courses/3230/db% https://www.sciencefacts.net/budding.html 20lecture/Lectures/a8Pattern.html  Characters of living organisms  Reproduction: It is the ability of an organism to reproduce its kind. Reproduction may be Asexual (without fusion between egg and sperm to form a fertilized egg), since It takes place by many different routes like binary fission (ex: Amoeba) or Sexual (carried out by the production of egg and sperm that fuse to form a fertilized egg that will develop to form the new individual).  Movement: Most organisms can crawl, walk, swim, and fly but micro-organisms move by special structures like (Cilia, Flagella, and Pseudopodia)  Metabolism: Is the sum of all chemical activities inside the cells and tissues of the organism. Characters of living organisms  Homeostasis: - Is a balanced internal state of physical, chemical, and social conditions maintained by living systems (or self-regulating control systems). - This is the condition of optimal functioning for the organism and includes many variables, such as body temperature and fluid balance, being kept within certain pre-set limits (homeostatic range). - Other variables include the concentrations of sodium, potassium, and calcium ions, as well as the blood sugar level, and these need to be regulated despite changes in the environment, diet, or level of activity. Each of these variables is controlled by one or more regulators or homeostatic mechanisms, which together maintain life. Characters of living organisms  Response to stimuli: - Responsiveness refers to the ability of an organism or a system within an organism to detect and respond to changes in its environment (temperature, light, sound, chemicals) or internal conditions, (hormones or neurotransmitters). - It involves the capacity to receive stimuli and generate appropriate responses to maintain homeostasis or adapt to new circumstances. - Examples include reflex actions, movement toward or away from stimuli (taxis), and physiological responses like changes in heart rate or hormone secretion.  Adaptation: - Is the ability of organisms to survive in a particular environment. Biological Organization There are three levels of biological organization: 1- Chemical levels: includes  The Atom: - Is the basic and smallest building block of matter, consisting of a nucleus composed of protons and neutrons, surrounded by a cloud of electrons. Protons carry a positive charge, neutrons have no charge, and electrons carry a negative charge.  The Molecule: - Is a neutral chemical structure consisting of two or more atoms held together by chemical bonds. Biological Organization 2- Cellular levels:  Organelle: - Is a specialized subunit, usually within a cell, that has a specific function (ex. mitochondria, Golgi bodies, and lysosomes).  Cell: - Is the basic structural and functional unit of all forms of life. Every cell consists of cytoplasm enclosed within a membrane; many cells contain organelles, each with a specific function (ex. Liver cells, muscle cells, and nerve cells).  Tissue: - It is a group of similar or dissimilar cells having the same origin, that together carry out a specific function (ex. epithelial tissue and connective tissue).  Biological Organization  Organ: - Organs are composed of various types of tissues working together to perform specific functions in the body. (ex. the heart, lungs, and liver).  Organ system: - A team of organs that cooperate in a larger function (ex. The human digestive system includes such organs as the tongue, stomach, and intestine)  Organism: - Is an individual living entity capable of carrying out life processes such as growth, metabolism, response to stimuli, and reproduction. (range from single-celled bacteria to complex multicellular organisms like plants and animals). Biological Organization 3- Ecological levels: Population: - All individuals of the same species living within a specified area. Community: - Populations of different species inhabit a particular area. Ecosystem: - Community (Living components) that interact with the surrounding non-living environment. Biosphere: - Is a combination of all of the earth’s ecosystems. (Planet Earth and all of its communities) https://www.google.com/url?sa=i&url=https%3A%2F%2Fm.youtube.com%2Fwatch%3F Diversity of life  The scientists classified the diversity of life into 6 kingdoms (others made it tens of kingdoms) and finer grouping according to structure, function, and other features.  Debatable issue.  Modern classifications are based on some other characteristics as DNA sequencing.  There are 3 domains of life diversity: 1. Archea 2. Bacteria 3. Eukarya  Diversity of life 1. Kingdom (Domain): Archea 2. Kingdom (Domain): Bacteria Prokaryotic Prokaryotic Single-celled Single-celled Microscopic Microscopic Divided by binary fission but no mitosis Divided by binary fission but no mitosis Autotrophic Autotrophic Live in salty lakes and hot springs The most diverse and widespread prokaryotic Its cell membrane has a branched Its cell membrane has an unbranched hydrocarbon chain attached to glycerol by hydrocarbon chain attached to glycerol by ether linkages ester linkages https://microbiologysociety.org/publication https://en.wikipedia.org/wiki/Bacteria /past-issues/archaea/article/comment- archaea-closet-pathogens.html Diversity of life  Domain 3: Eukarya  Kingdom 3: Protists - Are mostly unicellular eukaryotes and some multicellular. They have cell walls. They are autotrophic and heterotrophic. Includes protozoa, eukaryotic algae, and molds.  Kingdom 4: Fungi - Eukaryotic (multicellular) as mushrooms or (unicellular) as yeast. They have cell walls like plants but have a substance called chitin rather than cellulose. - They are heterotrophic and saprotrophic meaning they decompose - so they break things down or are parasitic. The body of a fungus is composed of thin filaments called hyphae. They secrete enzymes, do external digestion and then absorb the resulting nutrients. Diversity of life Kingdom 5: Plantae - Includes terrestrial multicellular eukaryotic plants, have cell walls with cellulose, also they are autotrophic i.e. use photosynthesis to make their energy from sunlight with CO2 and release O2. - Their growth is restricted to meristems - which are layers of dividing cells. - They are non-motile. https://www.slideshare.net/lhettinger/kingdom-plantae Diversity of life  Kingdom 6: Animalia - Includes multicellular eukaryotic (no cell wall) organisms, - Developed from the blastocyst, - It has nervous and hormonal control systems, - Heterotrophic, ingest other organisms (feed on organic matter), - Undergoes cell division to enable growth. https://www.etsy.com/au/listing/641627293/animalia-digital-latin-poster  Protista https://www.pinterest.com/pin/characteristics-of-protists-kingdom-- 240309330109512368/ Scientific Method (framework of scientific research) 1. Observation For example: Some Sun rays exposed Critical questions peoples suffer from Skin cancer Develop 2. Hypothesis Make 3. a Prediction that can be tested Perform 4. Experiments Further 5.RESULTS experiments Develop a theory and Interpretation New hypothesis principle & Conclusions  For reading only ….. Types of Nutrition in Biology  Autotrophs are known as producers because they are able to make their own food from raw materials and energy, include plants, algae, and some types of bacteria.  Heterotrophs are known as consumers because they consume producers or other consumers. Dogs, birds, fish, and humans are all examples of heterotrophs  Herbivores organisms that eat plants occupy the second level. Carnivores (organisms that eat meat) and omnivores (organisms that eat plants and meat) occupy the third level. Both primary (herbivores) and secondary (carnivores and omnivores) consumers are heterotrophs, while primary producers are autotrophs.  A third type of heterotrophic consumer is a detritivore. These organisms obtain food by feeding on the remains of plants and animals as well as fecal matter.  Also, Read and watch …. ❑Biology (concepts and connections), 9th Edition by Neil A. Campbell, Jane B. Reece, Martha R. Taylor, Eric J. Simon, and Jean L. Dickey. Pearson Benjamin Cummings, San Francisco, CA 94111, 2011. ❑Biology, 6th edition by Eldra P. Solomon, Lina R. Berg, and Diana W. Martin. Publisher: Brooks/Cole, Thomson Learning, 2002, ISBN: 0-03-033503-5.  https://www.youtube.com/watch?v=MB6mE6weCS4  https://www.youtube.com/watch?v=oID1h-zL- uw&list=PL6CpJGY2lfZfBbs0Jje2b5xbb013qbw6F&index=5  https://www.youtube.com/watch?v=c6Gp2R0wzhU