general-zoology-lec-m1-3.pdf

lOMoARcPSD|44387785 General Zoology (Lec) M1-3 Foundation of Zoology (Centro Escolar University) Scan to open on Studocu Studocu is not sponsored or endorsed by any college or university Downloaded by Agatha De Los Reyes (d...

lOMoARcPSD|44387785 General Zoology (Lec) M1-3 Foundation of Zoology (Centro Escolar University) Scan to open on Studocu Studocu is not sponsored or endorsed by any college or university Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 GENERAL ZOOLOGY LECTURE Module #1, #2, and #3 ▪ Proposed that animals be grouped MODULE #1: HISTORICAL into blooded and non-blooded. BACKGROUND OF THE Works of Aristotle: DEVELOPMENT OF ZOOLOGY De Generatione Animalium (Generation of ZOOLOGY Animals) Historia Animalium (History of Animals) De Partibus Animalium (Parts of Animals) - Known as animal science. - This is one of the fields of biological sciences that deals with animals. - It studies about the morphological, anatomical and physiological characteristics of animals, from their microscopic to their macroscopic structures. - It also includes the evolutionary, taxonomical and ecological perspectives on animal life. - Animals are also known as fauna. HISTORY CRO-MAGNONS In the Ancient Greeks, the systematic study of Etching and cabe sketches of animals as animals became rational, which as encouraged by documentations the extensive descriptions of living things. Example: deer, fish, and raindeer ANCIENT SCIENCE STONE AGE Hellenic Period (400 – 330 BC) Focused on the work of Aristotle 1.8 million years to 18,000 years BC Wall pants; engraved bones ARISTOTLE (1650-1850) Example: deer reproduction - Created the science of biology, attempted a comprehensive classification of animals and established some type of hierarchy of MEDIEVAL TIME animals based on the logic of structure in his zoological works. - He is considered as the Father of Zoology Early to late middle aged (1200s) and Father of Biology. Important time period for the field of science - He collected facts about 500 animals. No zoological application - Devised the 1st Classification System of Used mythology and folklore to describe Animals natural history GRAVOSO, Danielle Samantha | Dent1I 1 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 Emphasized the works of Sir Albert the EARLY MODERN ERA Great 15th to 17th Centuries Many notable scientists have contributed to ALBERTUS MAGNUS the development of Zoology - Albert the Geat (1193-1280) - Cited animals according to their genus, PIERRE BELON dwelling places, and motion. - Translated the version of “On Animals, a - Noted anatomical similarities between Medieval Summa Zoology”, continuation the human skeleton and that of birds. of Aristotle’s observation in De Animalibus. - Published La Nature and Diversite Les - Gave attention to both terrestrial and Poisions (1551) that contained illustrations aquatic animals. of his observations on fishes, marine - Used dissection to connect behavior mammals and birds. functions to internal structures. EDWARD TOPSELL PHYSIOLOGUS - Famous Natural Historian - Medieval literature associated with specific - Published Historie of Four-Footed animal and character trait Beastes (1607) and Historie of Serpents (1608), contained mythological and observational combination of animals primarily to serve the religious context in the PLINY THE ELDER Bible. - Combined fact and fantasy for his studies of Natural History (Historia Naturalis) ANDREAS VESALIUS - Natural History is an encyclopedia compilation of myths and facts about - Introduced Modern Western Medicine with celestial bodies, geography, animals and his human anatomy treatise, De humani plants, metals and stones. corposis fabrica. - The said material consists of 37 volumes - He was considered as a great anatomist where Volume VII to XI are about Zoology and illustrator, and used animal parts to in which Volume VIII deals with land show structures such as the kidney. animals. CONRAD GESSNER (1516-1565) GALEN - Father of Modern Zoology - Dissected animals for his studies in - Contributed to the 16th century progression human anatomy, and his works became of Zoology the standard for use in medicine throughout - History Animaum is a 5-volume the Middle Ages. bibliography of his knowledge of plants and animals. It is considered as the starting point of modern zoology. GRAVOSO, Danielle Samantha | Dent1I 2 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 - He used the same method of classification MARCELLO MALPIGHI (1628-1694) and JAN as Aristotle by ordering data and SWAMMERDAM (1637-1680) observations on fish, insects, birds, etc. - Discovered the role of capillaries added to the body of information about animals. WILLIAM HARVEY (1578-1657) - “Anatomical dissertation concerning the ANTOINE VAN LEEUWENHOEK (1600s- motion of the heart and blood” 1700s) - He demonstrated the circulation of blood and functions of the heart, arteries and - Made the 1st simplest microscope (single veins. lenses, 25x to 250x magnification) ▪ One of the 1st scientists to observe microorganisms ▪ Introduced the term “animalcules” HANS AND ZACCHARIAS JANSSEN which means tiny creatures - Was said to be the ones who invented - 1st to see live bacteria and protozoa. the first simple and compound - Father of Microbiology, Bacteriology and microscope with 3x and 9x Protozoology. - Microscopy then became the backbone of magnifications, but they were not given the identifying and understanding the proper recognition, because they never microscopic structures of both macroscopic published their work. and microscopic organisms. ROBERT HOOKE (1665) CAROLUS LINNAEUS (1707-1778) - Improved the compound microscope. - Observed the cork of plant and saw tiny - Father of Modern Taxonomy boxes which he called cell. ▪ Introduced the “Binomial System of - In his published book, Micrographia Nomenclature” (1665), presented the first published ▪ Scientific names contain the genus and species depiction of a microorganism, the microfungus Mucor. - Systema Naturae ▪ Introduced his taxonomy, published - He became Father of Cellular Biology. in Netherland. ▪ Marked the beginning of the modern system of classification and still in JOHN RAY (1627-1705) practice all over the world. - Sought to understand and classify all known animals based on internal physical characteristics like anatomy, and GEORGES CUVIER (1769-1832) divided birds into land and waterfowl in - Did not only established many of the which he included whales and dolphins as special group among fishes. fundamental taxonomic groups used by modern zoologists, but together with Lamarck studied invertebrates and vertebrates, respectively, and established the relationships of fossils to recent forms. GRAVOSO, Danielle Samantha | Dent1I 3 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 JEAN-BAPTISTE LAMARCK (1774-1829) CHARLES DARWIN (1809-1882) - Advocated the Theory of Inheritance of - Father of Biology Acquired Characters along with the tree On the Origin of Species: of life - Controversial figure in the study of evolution Natural Selection Theory (published 19th - Predecessor of Schwann and Schleiden century) concerning the cell theory. ▪ All species have come from a - Best known for his Lamarckism, a theory common ancestor and have evolved of evolution which says that acquired through the process of natural characteristics are inheritable. selection. MATTHIAS SCHLEIDEN AND THEODORE NIKOLAAS TINBERGEN (1907-1988) SCHWANN - One of the founders of ethology, used - Formulated the first unifying principle of field experiments by altering the biology, the Cell Theory, stating that, “The surroundings of the wasp’s burrows to cell is the structural unit of all living observe how they go back to them after things.” hunting. RUDOLF LUDWIG CARL VIRCHOW (1821- DESMOND MORRIS 1902) - Applied ethological techniques to humanity - Formulated the other component of the in his bestseller “The Naked Ape.” Cell Theory, which states that “Cell came from pre-existing cell.” EDWARD O. WILSON (1929) ROBERT BROWN (1831) - American sociobiologist and entomologist worked and wrote the preservation of - Discovery of the nucleus in plant cell. natural habits and creatures. - But one of the challenges now to modern zoology is the destruction of vast of the animal habitats, and the extinction of many ALFRED RUSSELL WALLACE (1823-1931) species where much of their natural - He came up with his Theory of Natural behavior cannot be observed. Selection before Darwin. - He defined a line, the Wallace Line, that separates the Indonesian archipelago in JAMES WATSON AND FRANCIS CRICK areas containing species of Australian origin and those of india origin. - First discovered the double helix - Father of Biogeography. structure of DNA in 1953. ▪ Due to his research on the basin of the river of Amazon. GRAVOSO, Danielle Samantha | Dent1I 4 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 8. EMBRYOLOGY – is the study of the LESSON #2: PRINCIPAL development of the embryo. DIVISIONS OF ZOOLOGY 9. ENTOMOLOGY – study of insects. EARLY MODERN ERA 10. ETHOLOGY – is the study of animal behavior. 11. GENETICS – is a field about heredity and variations. 12. HERPETOLOGY – study of reptiles and amphibians. 13. HISTOLOGY – study about tissues and microscopic anatomy of cells. The same as the other 2 Divisions, Zoology is composed of Sub-branches, these are: 14. ICHTHYOLOGY – study of fish. 1. ANATOMY - is concerned with the 15. MORPHOLOGY – is about the forms or internal features of animals, so this is with external features of animals. the involvement of dissection. 16. ORNITHOLOGY – deals with the study of 2. ANTHROZOOLOGY – study of birds. interaction between humans and other animals. 17. ORGANOLOGY – is about the different organs of the body. 3. ARACHNOLOGY – deals with the study of spiders and related species known as 18. PALEONTOLOGY – is the study of arachnids (scorpions, harvestmen). fossils. 4. ARCHAEZOOLOGY/ZOOARCHAEOL 19. PALEOZOOLOGY – is specifically for the OGY – study of dead animals (faunal study of animal fossils. remains) that includes their bones, shells and other body parts. 20. PATHOLOGY – is concerned with the diseases. 5. CETOLOGY – branch of zoology that deals with the study of marine mammals 21. PARASITOLOGY – study of parasites. that include whales, dolphins. 22. PHYSIOLOGY – is the study of the 6. CYTOLOGY – is everything about the functions of the different structures of the cell. body. It is concerned with animal digestion, respiration, and other 7. ECOLOGY – study of organisms and metabolic processes. how they interact with the environment around them. 23. TAXONOMY – is involved with the classifications of organisms. GRAVOSO, Danielle Samantha | Dent1I 5 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 LESSON #3: CURRENT EVOLUTION SIGNIFICANCE OF ZOOLOGY Zoology gives so much information about the past that are essential in knowing our ancestors and in Zoology is important in various fields concerning understanding the present forms. animals, such as: GENETICS ANATOMY AND PHYSIOLOGY Zoology includes the study of the genes of animals, Knowing the structural characteristics of animals is for us to have insights on their biology. It helps us to become aware of their functional properties. It understand the physiology and behavior of animals helps us understand how animals live, grow, for their protection. change and survive, for us to help preserve them, and prevent animal extinction. ENVIRONMENT / ECOSYSTEM MODULE #2: ANIMAL The science of zoology is concerned also with the ORGANIZATION, CELL DEVISION relationship of the organisms to their environment. AND INHERITANCE This is to know if the population is fit to stay in the environment and/or to determine if the environment can sustain the needs of the population. Knowing This is concerned with the organization of the such information is essential for the concerned animal body, which is specifically focused to one individuals or personalities to know how they of the most significant features, the cell. manage and sustain the life of various organisms and their habitats as well. LESSON #1: CELL STRUCTURES AGRICULTURE AND FUNCTIONS Zoology gives information on the roles of animals in The presence of cell is one of the common the field of agriculture. This helps in the characteristics that makes organisms living. identification of those animals that are good in the development and growth of crops, and those that Though the cell is identified as the smallest may cause damage as well. Equipped with such structure in an organisms’ body, it is considered as knowledge, the farmers will be able to expose their the most important characteristics of living things, crops to useful organisms, and to protect their because it carries all the biological processes crops to destructive ones. that life needs. The cell was discovered by Robert Hooke (1665) MEDICAL FIELD when he studies corks of plants and observed those tiny boxes or pores that look like the rooms in Many diseases known are passed on to humans monastery, where he coined the term “cell.” via animals. Armed with this knowledge and information, we are able to better understand the Theodore Schwann, a zoologist, and Matthias characteristics of animals on how they cause those Schleiden, a botanist, who proposed that cells diseases, and this gives us the idea on how to are the basic building blocks of all living things. counter them and protect ourselves. Rudolf Virchow observed that cells produced new cells through cell division, and proposed GRAVOSO, Danielle Samantha | Dent1I 6 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 that living cells arise only from other living - Multicellular Organisms (Plants, Protists, cells. Fungi & Animals) B. PROKARYOTIC CELL - “False” Nucleus - Non-membrane bound organelles - Unicellular (Organisms/Archaea & Bacteria) BASIC PARTS OF THE CELL CYTOLOGY Plasma Membrane Cytoplasm - Science about the cell. Nucleus TWO BASIC CELL TYPES ORGANELLES - Basic cell parts that perform the physiological activities of the cell. TYPICAL ANIMAL CELL A. EUKARYOTIC CELLS - “True” Nucleus - Membrane-bound and non-membrane bound organelles GRAVOSO, Danielle Samantha | Dent1I 7 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 CELL MEMBRANE / PLASMA CYTOPLASM / PROTOPLASM MEMBRANE - Also called the protoplasm. - Located inside of the cell. - It separates the cell from its external - It contains the chemical elements, and environment. tiny structures, the organelles, that are - The outer lining of the cell which encloses responsible in performing the metabolic all other cell organelles. activities of the cell. - A semi-permeable membrane that ▪ “Living Substance” – contains the controls the moving of materials into and organelles that perform all the out of the cell. physiological properties of the ▪ Envelope – covers and protects the cell. cell and gives shape to the cell. ▪ Cytosol – 70% cytoplasm. ▪ Bilayer Phospholipid ▪ Gel-like material a. Phosphate layers: polar heads; a. Sol: semi-liquid hydrophilic. b. Gel: semi-solid b. Lipid layers: non-polar tails; These organelles are: hydrophobic. ▪ Semi-permeable – selects materials that pass through it and regulates ENDOPLASMIC RETICULUM the movement of materials. ▪ Fluid Mosaic Model – contains - System of membranous tubules and various materials or molecules sacs. (phospholipids, cholesterol, and - “Circulatory system of the cell” proteins). ▪ Internal Transport System ▪ Allows molecules in the cell to move from one part to another. CELL WALL a. Rough Endoplasmic Reticulum – lined - It has none in animal cells. with ribosomes. For protein synthesis and - A rigid layer that surrounds the plant transport. cells. It is located outside the cell b. Smooth Endoplasmic Reticulum – has no membrane. ribosomes. It transports other materials ▪ Rigidity – gives support and other than protein. protection. ▪ Freely Permeable – porous; no RIBOSOMES direct effect on the movement of materials in and out of the cell. - Most common organelles in almost all cells. - It is not surrounded by a membrane. Components depend on the - Spherical, non-membranous organelle for organism: protein synthesis. a. Plants: with cellulose - It is scattered around the cyptoplasm. b. Fungi: with chitin ▪ Protein Micro-machines – sites for protein synthesis. ▪ Free Ribosomes – floating in the cytoplasm. It has the size of 70S in prokaryotes. ▪ Attached Ribosomes – line the membranes of endoplasmic GRAVOSO, Danielle Samantha | Dent1I 8 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 reticulum. It is the size of 80S in CENTROSOMES / CENTRIOLES eukaryotes. ▪ Polysome/Polyribosome – group - Organizing centers for microtubule that of 80S ribosomes working together serve as the skeletal system of the cell. translating mRNA to polypeptides. - Contain 2 bundles of microtubules at the right angle to each other. - They are also responsible in the MITOCHONDRIA formation of spindle fibers which are important in cell division. - “Powerhouse of the Cell” ▪ Centrosomes is the house of the - Large organelles second to nucleus and centrioles. chloroplasts. - It is responsible in the production of Adenosine Triphosphate (ATP) as the LYSOSOME (suicide sacs) energy source. - It also act like a digestive system to - Tiny sac produced by Golgi body. breakdown nutrients to produce energy - They secrete enzymes, called lysozymes rich molecules (aerobic respiration). which are for digestion. ▪ ATP Manufacturer – metabolize ▪ It keeps the cell clean as it digests carbohydrate and fatty acid to excess and worn out organelles generate energy. and engulfed bacteria or viruses. ▪ Semi-autonomous Organelles – have own DNA, so can produce by PEROXISOME itself by dividing. ▪ Double-membrane Organelles – - Formerly known as a microbody. smooth outer membrane, folded ▪ Oxidative Organelle – it contains inner membrane. enzymes that oxidizes fatty acids a. Cristae: infoldings. and amino acids. Byproduct is hydrogen peroxide. ▪ Chemical Detoxification – GOLGI APPARATUS / GOLGI BODY oversees reactions that neutralizes - Also called Golgi Complex. free radicals, which cause cellular - Processing and Packaging Plant, and damage and cell death. Secretory Vesicle. - It collects materials from the organells VACUOLE that are needed to be disposed through secretory vesicles formed at the cell - Storage bubbles found in cells membrane. - A membrane bound fluid sac. - They are also lysosome builder. As - It stores large amount of various lysosomes are vesicles with protein materials, like organic, and inorganic enzymes pinched off by Golgi body to molecules. the cyptoplasm. - Transports needed materials into the cell via ▪ Cisternae – fused flattened sacs endocytosis. or folds. Also called dictyosome. ▪ Subordinate Role – assisting in ▪ Transport Agent – involved in the exocytosis and endocytosis. distribution of lipids around the cell. GRAVOSO, Danielle Samantha | Dent1I 9 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 CYTOSKELETON PLASTIDS - Complex network of interlinking - Storage organelles. filaments or tubules. - They store products like starch for synthesis - “Cell Skeleton” of fatty acids and terpenes. 3 Structures: ▪ Intermediate Filaments - provides strength and support. CELL THEORY ▪ Microfilaments – contracile (made of actin); for cell movement and Three Tenets of Cell Theory: cytokinesis. ▪ Microtubules – rigid, hollow tubes All living organisms are composed of cells. (made of tubulin); it maintains the Cells are structural and organizational unit cell shape. It also forms the of life. centrioles (spindle fibers). All cells come from pre-existing cells. CHLOROPLASTS LESSON 2: CELL CYCLE AND - None in animal cells. - Sites of photosynthesis. CELL DIVISION CELL CYCLE FLAGELLA AND CILIA - For cell movement. ▪ Cilia – short, hair-like and numerous in number. ▪ Flagella – long, thread-like, and fewer in number. NUCLEUS - Normally the largest organelle - “Brain of the cell” - It controls all the metabolic activities of the cell. ▪ Nuclear Envelope – double - A series of events that takes place in a membrane with many pores. It also cell as it grows and divides. controles the movement in and out of the nucleus. Cell division occurs during growth and repair ▪ Nucleoplasm – enclosed by a processes. Cell cycle has the following basic double membrane lining, called stages: nuclear membrane. It is where chromosomes, containing genetic Mitosis – division of nucleus. The materials, DNA are loccated. distribution of chromosomes between two ▪ Nucleolus – a spherical structure for daughter cells. the formation of ribosomes. Cytokinesis – division of the cytoplasm between two daughter cells. GRAVOSO, Danielle Samantha | Dent1I 10 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 Interphase – cell grows and carries out S (DNA synthesis) its various metabolic processes during interphase. - Growth continues, but this phase involves DNA replication. - Hence, each chromosomes consist of two sister chromatids. INTERPHASE - Last up to 8 hours. ▪ Each cell needs a complete and identical set of DNA. G2 (Second Growth or Gap Phase) - Also known as UGROWTH 2. - Serves as checkpoint to determine if the cell is ready for the next process. - Protein synthesis is also done in preparation for cell division. - This phase prepares the cell for division. It includes the replication of the - A cell spends most of its time (93%) in what mitochondria and other organelles, is called the interphase. synthesis of microtubules and protein. - During this phase, the cell grows and - Lasts up to 4 hours. replicates its chromosomes, and ▪ These microtubules and proteins will prepares for cell division. make up mitotic spindle fibers and - The cell then leaves interphase, undergoes chromosome condensation. mitosis, and completes its division. It has three parts: G1 (First Growth or Gap Phase) MITOSIS / MITOTIC PHASE (M) - Also known as UGROWTH 1. - It is when organelles duplicates and busy performing their metabolic activities. - With this, the cell is increasing in size. - This phase is the early growth phase of the cell. - Lasts up to 11 hours. ▪ Remember each new cell needs a complete set of organelles. G0 - Quiescent stage. - Metabolically active cell - Not dividing cell GRAVOSO, Danielle Samantha | Dent1I 11 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 DNA is tangled up into a substance of chromatin. The chromatin is packaged on the chromosome. - These includes events associated with partitioning chromosomes between two daughter cells and the division of the cytoplasm (cytokinesis). - The process by which the cell nucleus a. HAPLOID CHROMOSOMES - One copy divides into the two identical cell nuclei. of genetic material subdivided into - In some human cells interphases lasts chromosomes. 15.3 hours, while mitosis lasts only.7 hours. b. DIPLOID CHROMOSOMES - Two copies - The type of cell division in which number of of genetic material subdivided into chromosomes remains constant in the chromosomes. daughter generations. - A form of nuclear division that produces daughter nuclei containing the same number of chromosomes as the parent nucleus. What is Cell Division? Biological Basis of Life ▪ Reproduction: to produce new individual of the same kind. Maintains the genome ▪ Keeps the genomic information consistent between generations. Cell Multiplication ▪ Increase in number of cells for a. HOMOLOGOUS CHROMOSOMES – growth, development and repair. have alleles for same genes at specific loci. Similar but NOT identical. CHROMOSOMES b. SISTER CHROMOSOMES – have the same alleles for each gene. Identical Must duplicate and separate during chromosomes. mitosis. Structures of the tightly packaged DNA. GRAVOSO, Danielle Samantha | Dent1I 12 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 - Centromeres of the chromatid pairs line up in the middle of the cell. - By the end of metaphase each sister chromatid has attached to the spindle fibers. Mitosis/Mitotic Phase occurs in 4 main stages: ANAPHASE PROPHASE - Chromosomes separate and move to - Chromosomes are now called chromatids opposite poles. because they doubled to form short thick - Each centromere divides. rods. - The spindle fibers pull the chromatids - A centromere connects the two halves of apart. the doubled chromatids. - Now, there are two identical sets of - Spindle fibers begin to form by the chromosomes. centrioles. - Once the chromatids are separated, they - Centrioles move to opposite sides of the are called daughter chromosomes. cell. - The nuclear membrane breaks down and nucleus disappears. TELOPHASE METAPHASE - When the chromosomes reach opposite sides of the cell the spindle fibers break up. GRAVOSO, Danielle Samantha | Dent1I 13 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 - The nuclear membrane begins to reform and nuclear envelope begins to appear. MEIOSIS - A furrow begins to develop between the two sets of chromosomes. CYTOKINESIS - The two identical cells completely divide and the cell membrane is completely formed. - Type of cell division in sexually reproducing organisms that reduces the number of chromosomes in gametes. ADDITIONAL TERMS - The production of new organisms is called reproduction. G2 (Second Growth or Gap Phase) ORGANISM DIPLOID GAMETE - An exact copy of the DNA is formed before Human 46 23 the cell division. Pea 14 7 - The double stranded DNA makes a replica, Fruit fly 8 4 or duplicate, of itself. Dog 78 39 - Each daughter cell receives the same genetic material as the parent cell. MEIOSIS I SPINDLE FIBERS - A fibrous structure from the cytoplasm which forms to the centriole. METAPHASE PLATE - Location where the centromeres line up in the center of the cell. In mitosis, two daughter cells are produced, INTERPHASE each with diploid chromosomes. - Chromosomes replicate. Whereas, meiosis produced four haploid cells. - Each chromosome consists of 2 identical sister chromatids. GRAVOSO, Danielle Samantha | Dent1I 14 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 PROPHASE I ▪ Re-condensation ▪ Tetrad chromosomes are visible. - Each pair of homologous chromosomes ▪ Terminalization: chiasmata at the come together to form a tetrad. ends. - Chromatin threads condense, coil and ▪ Nucleolus vanishes and nuclear shorten to become chromosomes. membrane breaks down. - The chromosomes are now visible under the microscope. METAPHASE I - Chromosomes are attached to the meiotic spindle and arranged at the metaphase plate. - Homologous chromosomes line up together 1. LEPTOTENE in pairs. ▪ Condensation of chromosomes ▪ Shortening and thickening of chromosomes ANAPHASE I ▪ Doubled chromosomes. 2. ZYGOTENE ▪ Pairing of homologous chromosomes ▪ Synapsis begins 3. PACHYTENE ▪ Observed with the complete - Separation of homologous chromosome, condensation of chromosomes each moving to opposite poles. ▪ Bivalent formed and crossing-over - Sister chromosomes remain attached. has occurred. - Spindle fibers attached to the centromeres of each pair. 4. DIPLOTENE ▪ The completion of the crossing-over of chromosomes. TELOPHASE I ▪ Coiling stage ▪ Chiasmata holds the homologous chromosomes. 5. DIAKINESIS ▪ The formation of four sister chromatids. GRAVOSO, Danielle Samantha | Dent1I 15 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 - Homologous chromosomes reached the - Sister chromatids separate to become poles daughter chromosomes, which are pulled - Nuclear envelopes form towards opposite poles of the cell. - Cytoplasm divides (cytokinesis) - The formation of two diploid daughter cells. TELOPHASE II - Nuclei reform. - Spindle fibers disappear. - Cytoplasm divides into two. MEIOSIS II CYTOKINESIS II - Cleavage of cytoplasm results in four daughter cells being produced, each with half the number of chromosomes as the parent cell. - It is just like mitosis, but remember the chromosomes did not duplicate in interphase II. - There is also two daughter cells produced in Meiosis II divide and each forms two haploid daughter cells. - So that, total of four cells are produced in the entire Meiosis. PROPHASE II - Two pairs of centrioles move to opposite poles of the cell. - Spindle fibers begin to form. - Nuclear envelope disappears. METAPHASE II - Chromosomes arrange themselves along the equatorial plane of the spindle. ADDITIONAL TERMS ANAPHASE II GAMETES - Centromeres split. - Reproductive cells that contain half the number of chromosomes as the normal body cells. GRAVOSO, Danielle Samantha | Dent1I 16 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 - In human, the sperm is the male gamete and the egg (ovum) is the female gamete. FERTILISATION - Occurs when the nucleus of the male gamete fuses with nucleus of the female gamete to form a zygote. ▪ Zygote refers to the fertilized egg which has a diploid number of chromosomes. ALLELE - Gene form for each variation of a trait of an organism. CROSSING-OVER - The exchange of genetic material by non- sister chromatids during late prophase 1 or meiosis. LESSON #3: THE GENETIC MATERIAL (DNA) Humans and almost all organisms are composed of DNA (Deoxyribonucleic Acid) which is a molecule that contains the genetic code of organisms, and thus considered as the genetic material. DEOXYRIBONUCLEIC ACID (DNA) - DNA stores all the information that a cell needs in order to grow and to carry out vital activities. - A molecule that carries the genetic information for it is important in the coding of protein and genetic information guide for life and its processes. GRAVOSO, Danielle Samantha | Dent1I 17 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 - It stores, copies and transmits genetic cytosine is paired with guanine, and adenine with information for the development and thymine. reproduction of organisms. - A biological macromolecule with structural unit, the nucleotide that is composed of sugar molecule, phosphate group, and nitrogenous base. - It has two twisted strands, called double helix, and described like a twisted ladder. ▪ The sides of the ladder is made up of alternating molecules of phosphate and sugar (deoxyribose) in which covalent bonds join the sugar of one nucleotide to the phosphate group of the next nucleotide, forming the sugar- phosphate backbone. ▪ Whereas, the rungs are composed of the nitrogenous bases: a. PURINE GROUP – adenine and guanine. The two strands of the double helix are antiparallel, b. PYRIMIDINE GROUP – cytosine which means that they run in opposite direction, and thymine. wherein the 5’ end of one strand matches with the 3’ end of the other. NUCLEOTIDE This orientation of the DNA strands permits base pairing by providing complementarity between the - The basic unit of DNA. two bases, which is important for DNA replication. - Nucleotides can be joined together to form long chains called polynucleotides. - Each nucleotide is made up of: ▪ A sugar called deoxyribose; CENTRAL DOGMA ▪ A phosphate group; and ▪ A nitrogen-containing base (adenine (A), cytosine (C), guanine (G), and thymine (T)). The sequence of the nitrogenous bases on one strand of a DNA molecule is matched in a particular way with the sequence on the other strand. This pairing is due to the different chemical structure of the bases. The cytosine and - Refers to the processes involved on how thymine which are the pyrimidines, have one the genetic information of the DNA is ring, and the adenine and guanine which are the converted into gene products, RNAs and purines, have two rings. proteins. The pyrimidines are paired with the purines, so that GRAVOSO, Danielle Samantha | Dent1I 18 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 DNA REPLICATION - In this process, DNA segment is copied into RNA molecules, the messenger RNA - By which DNA makes new DNA. (mRNA). - This is a biological process in which DNA - The mRNA leaves the nucleus and goes makes a copy of itself. out to the cytoplasm to direct protein It has four steps: synthesis. - This time, thymine is replaced by uracil. FORK FORMATION – the split of two strands of DNA, in which each of the single strands becomes the template of TRANSLATION the new strand of a complementary DNA. - In which proteins are made from RNA. This is the pairing of the bases in the - This is a process when mRNA acts as a template strand, the adenine paired with template in the synthesis of protein. thymine, and guanin with cytosine. - Sequence of mRNA codons used to make polypeptide. PRIMER BINDING – binding of primers to DNA template by complementary base pairing to start the replication. ▪ A primer refers to the nucleotides of ADDITIONAL TERMS DNA, with 18 to 24 base pairs in length. RULE OF BASE PAIRING ELONGATION – lengthening of the DNA - Adenine (A) always bonds with thymine (T). by the addition of nucleotides to the 3’ - Cytosine (C) always bond with Guanine (G). end of the newly synthesized strand. The - Adenine and Thymine are thus called DNA nucleotides added are specified by the complementary bases. template strand as to whether A, T, C, or G. - Complementary bases are joined together by hydrogen bonds. TERMINATION PHASE – end of DNA synthesis. This happens when two replication forks meet, DNA is unwound, GENES and gaps are filled. - Small segments of DNA that code for the production of polypeptides. - Each gene stores a message that determines how a protein should be made in a cell. - The message stored by a gene is known as the genetic code. TRIPLET CODE / CODON - Three bases code for one amino acid. DNA RNA TRANSCRIPTION The sugar unit is The sugar unit is - When DNA makes new RNA. deoxyribose. ribose. GRAVOSO, Danielle Samantha | Dent1I 19 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 The nitrogen- The nitrogen- Dominance, and (2) Law of Co-Dominance, and containing bases are containing bases are (3) Multiple Alleles. adenine, thymine, adenine, uracil, cytosine and guanine. cytosine, and guanine. It is a double stranded It is a single stranded molecule. molecule. 3 MENDELIAN LAWS OF The ratio of A:T and There is no fixed ratio INHERITANCE C:G is 1:1. between A and U, or between C and G. It is a permanent It is a temporary LAW OF SEGREGATION molecule in the molecule and is made nucleus. only when needed. - Says that everyone has two versions Unlike DNA. It can (alleles) for each trait, that randomly move out of the segregate during meiosis. nucleus. - This means that in fertilization, when an egg is joined by a sperm, one new organism is produced, with genotype consisting of the alleles contained in the gametes. LESSON #4: INHERITANCE - Hence, according to the law, two members of a gene pair segregate from each other PATTERNS OF ANIMALS during meiosis, each gamete has an equal probability of obtaining either member of the gene. The characteristics of organisms are influenced by genes, which are pieces of DNA that are in the chromosomes. These genes are responsible in carrying the characteristics of organisms from the parents to their offspring. This is stated in the Laws of Inheritance. There are 3 Mendelian Laws of Inheritance, these are: (1) Law of Segregation, (2) Law of Independent Assortment, and (3) Law of Dominance. Whereas, the 3 Non-Mendelian Laws of Inheritance are: (1) Law of Incomplete GRAVOSO, Danielle Samantha | Dent1I 20 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 LAW OF INDEPENDENT ASSORTMENT LAW OF DOMINANCE - This says that the alleles of two or more Dominant alleles always hide recessive alleles. different genes are categorized into - It states that each individual has two gametes independently of one another. copies of gene, these are the dominant - This means that the allele of a gamete for traits and the recessive traits. one gene does not influence the allele of ▪ Dominant traits are inherited another gene. characteristics that are - This law was introduced by Gregor Mendel phenotypically expressed in after doing the dihybrid crosses. Where he heterozygous organisms. noticed that new combinations of traits ▪ Recessive traits are present at the emerged from the cross of two parents with gene level, but are masked and different combinations of two traits. unexpressed. - This shows that each of the two alleles is inherited independently from the other, with a 3:1 phenotypic ratio for each. GRAVOSO, Danielle Samantha | Dent1I 21 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 - An individual has only two copies of each 3 NON-MENDELIAN LAWS OF gene, but many different alleles are within a INHERITANCE population. LAW OF INCOMPLETE DOMINANCE - This occurs when the dominant allele does not completely mask the recessive allele, so an intermediate phenotype is observed and this results to the blending of the two alleles. LAW OF CO-DOMINANCE - The genetic traits of different alleles of the same gene-locus are both expressed phenotypically. - This means both alleles are seen in the phenotype at the same time. ADDITIONAL TERMS ALLELES - Different forms of the same gene. - They occupy the same relative positions on a pair of homologous chromosomes. PHENOTYPE LAW OF MULTIPLE ALLELES - Refers to the expressed trait in an organism. - This means that genes exist in several - The phenotype of an organism is the result different forms. of its genes and the effects of its environment. GRAVOSO, Danielle Samantha | Dent1I 22 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 GENOTYPE - Genetic makeup (pairs of alleles) of an organism, that is, the combination of genes in an organism. ▪ An organism is said to be homozygous for a trait if the two alleles controlling the trait are identical, for example, TT or tt. ▪ An organism is heterozygous for a trait if the alleles controlling the trait are different, for example, Tt. DOMINANT ALLELE - Expresses itself and gives the same phenotype in both the homozygous and heterozygous conditions. RECESSIVE ALLELE - Does not express itself in heterozygous condition - It expresses only in the homozygous condition. PUNNETT SQUARE - Diagram to determine the genotype and phenotype of a cross or a breed. - Usually having 4 boxes = monohybrid - 16 boxes = dihybrid MONOHYBRID CROSS - Method of determining the inheritance pattern of a trait between 2 organisms. DIHYBRID CROSS - Is a cross between 2 parents that differ by 2 pairs of alleles. GRAVOSO, Danielle Samantha | Dent1I 23 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 MODULE #3: CONCEPTS OF LESSON #1: HISTORY OF EVOLUTION EVOLUTION INTRODUCTION Changes are expected to occur through a period of time among populations, this is rooted from the idea of organic evolution (“descent with modification”) as described by Charles Darwin. EVOLUTION - Change in the characteristics of a species over several generations and relies on the process of natural selection. - These characteristics are the expressions of genes that are passed on from parent to offspring. PRE-DARWINIAN THEORIES OF CHANGE GENE FREQUENCY EMPEDOCLES AND ARISTOTLE - Living organisms undergo changes through time. - Sewell Wright - Allele Frequency - Relative frequency of an allele, expressed GEORGES-LOUIS BUFFON as a fraction or percentage. ▪ Fraction of all chromosomes in the population that carry the allele. GRAVOSO, Danielle Samantha | Dent1I 24 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 - Specific organs of related animals have conditions thereatening their survival. structural variations. - Change in organisms is brought about In the process of natural selection and evolution, by action of the environment. more traits and alleles emerge, and they are all - There is special creation of species, so stored in a “gene pool.” change is degenerate (for example, apes as degenerate humans). GENE POOL ERASMUS DARWIN - The collection of ALL the alleles for all the traits and genetic variations of a certain population that is necessary for evolution (traits include coat, color, ear size, eye color, eye shape, etc). - Some genes may have little to none at all variation among the population. - All organisms share a common ancestor. POPULATION - A group of organisms of the same JEAN BAPTISTE LAMARCK species with a common set of genes living in a particular area for a given time where genetic changes are passed on to every generation. Variations among individuals in a population may occurs due to: 1. Independent Assortment of - Basis of his theory is the widely accepted Chromosomes in the gametes THEORY OF INHERITANCE during his 2. Crossing Over among the homologous time (need is the driving force to develop chromosomes new organs, or modify existing organ) on 3. The Chances of an Egg Getting Fertilized the other hand. by a Sperm - DISUSE leads to degeneration of 4. Chromosomal Arrangements organs. 5. Mutation - Species could not become extinct, it simplye evolves into different species is his conclusion. POPULATION GENETICS - A biological field dealing with the genetic make-up of populations and the factors LESSON #2: EVOLUTION AND changing its composition. GENE FREQUENCY - Abstract Mathematical models are used to analyze and predict genetic patterns and variations. Organisms do not evolve alone, instead, organisms evolve collectively – as a population – when exposed to harsh environmental GRAVOSO, Danielle Samantha | Dent1I 25 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 HARDY-WEINBERG THEOREM LESSON #3: SPECIES AND SPECIATION - Allele frequencies remaind constant (or at equilibrium) over generations in the absence of distressing factors. The equilibrium can be disrupted by: a. MUTATIONS – introduction of new alleles. b. NATURAL SELECTION & NONRANDOM MATING – occurrence of beneficial or detrimental alleles. c. GENETIC DRIFT – the random fluctuations in the chances of allele frequencies, especially in small populations. d. GENE FLOW – inbreeding of two populations to produce another populations. - Rarely applies in reality due to random natural events. SPECIES ASSUMPTIONS IN THE HARDY-WEINBERG THEOREM: 1. Population must be large. 2. Non-existence of migration among the population. 3. Mutations must not occur, except during - Basic unit of classification mutational equilibrium where wild type to - Group of populations that can interbreed mutant mutations and vice versa are equal. and as a consequence genes either actually 4. Sexual reproduction must be random within or potentially exchanged, referred to as the population. biological species concept. - Group of populations that independently evolved, this on the other hand is phylogenetic species concept. GRAVOSO, Danielle Samantha | Dent1I 26 Downloaded by Agatha De Los Reyes ([email protected])  lOMoARcPSD|44387785 ▪ Parents plants produce offspring that SPECIATION are polypoid. - Formation of new species. - INTERBREEDING is avoided between subpopulations, so there is reproductive isolation or non-occurrence of gene flow. PARAPATIC SPECIATION - Para (near) and patric (homeland). - Occupying overlapping geographic areas; - Adjacent populations maintaining common FORMS OF SPECIATION contact along a common border. - Speciation happens within demes or small, local populations. - Members experience different selection pressures in a deme. Example: All of the frogs in a particular pond. SYMPATRIC SPECIATION - Sym (same) and patric (homeland). - This involves speciation occurriung within a parent species remaining in one location. - Speciation happens within a single population. Example: Indigobirds from Afrida – Cat Family (Felidae) Ancestral species splits into 2 or more descendant species that are genetically different from one another and can no longer interbreed. PERIPATRIC SPECIATION - New species is formed from an isolated ALLOPATRIC SPECIATION peripheral population. - Organisms are closely adjacent but do not - Allo (other) and patric (homeland). overlap. - This involves the geographic separation of populations from a parent species and subsequent evolution. - Speciation happens if there are geographic barriers (example: mountain range or river) between subpopulations. - Members of these separated groups can no longer mate successfully due to adaptations to different environments or genetic drift. Example: ▪ Finches on the Galapagos Islands. GRAVOSO, Danielle Samantha | Dent1I 27 Downloaded by Agatha De Los Reyes ([email protected])