Science 11 Notes PDF

MODULE 1: PERSPECTIVES ON LIVING SYSTEMS We are dependent on our immediate environment for: 1. Water 2. Food 3. Shelter 4. Clothing Knowledge of our environment -> systematic observations (share & pass to next generations) Knowledge was transmitted orally: 1. Telling stories 2. C...

MODULE 1: PERSPECTIVES ON LIVING SYSTEMS We are dependent on our immediate environment for: 1. Water 2. Food 3. Shelter 4. Clothing Knowledge of our environment -> systematic observations (share & pass to next generations) Knowledge was transmitted orally: 1. Telling stories 2. Chanting and music 3. Creation of visual arts Knowledge was transmitted experientially: 1. Direct teaching of younger generations in hunting and gathering expeditions 2. Experiencing living systems both physically and metaphorically in nature walks, rituals, and dream journeys Kinds of Knowledge Transmitters: play a role in teaching knowledge for survival 1. Elders a. Perform special roles b. Esteemed for their knowledge 2. Storyteller a. ability to tell stories in a memorable and engaging way b. Teaching about the life of a tribe: stories, myths, legends, and how tribe experiences were recorded 3. Hunter a. Knowledge of wildlife b. Read signs c. Create tools and weapons d. Teach knowledge of environment without words 4. Gatherer a. Knowledge of fruits, animals, herbs and uses 5. Farmer a. Knowledge of seasons b. Signs of the wind and sky Indigenous Knowledge Systems and Practices (IKSP) - Myths, legends, and folklore - Traditional knowledge passed on - Observations from the natural world - Affects art and oral literature - Knowledge of geography and climate - “Read” signs from nature (wind, animal behavior, appearance of indicator leaves and flowers) - Predict future environmental conditions - Create inventions/technologies for: a. Domestication of food, storage, preparation b. Herbal-based medicines c. Clothing and transportation d. Astronomy e. Agricultural and industrial practices Interplay among elements in the local living systems give rise to applications: 1. Indigenous knowledge systems 2. Modern scientific methods Biocultural knowledge knowledge that is rooted both in the natural environment and what is readily available, grounded on people’s cultures (values and norms) Indigenous cultural communities: holistic worldview Living Systems from Antiquity to the Renaissance (Holistic Worldview) 1. Written word - track of their livestock and grains, made bread, wine, and cheese - recorded astronomical data to keep time and predict the weather - need for myths and legends - human connection to the gods – the Priestly Class - exclusive access to the stored knowledge - knowledge was in the hands of the priest (political power & surplus production) Invention of the written word - knowledge production, transmission, and storage Oral cultures - Storyteller was the keeper of knowledge Literate cultures - knowledge was stored & transmitted - cuneiforms in clay tablets - Sumerians - papyrus scrolls - Egyptians - Bamboo, bone, wood tablets - east Asian - wax tablets - Romans - parchment - medieval Europe - paper - Chinese - Qu’ran copies Literacy - expansion of collective knowledge beyond the Storytellers’ collective memories - development of more complicated trains of logic, of more abstraction and thus analytical knowledge, reflection, and introspection, which were very difficult to keep track of in story, song, or art Sumerians and their Knowledge of Biology (4500 – 1750 BCE) - clay tablets written in cuneiform - medical lore: treatment of disease, the use of herbs and animal material - Sumerian Belief System: empirical and the magical; demon possession - sacrifice of animals would cure this possession through the transmission of the demon from the afflicted person to the lamb as a sign of compassion to the family. Greek Philosophers and their Theories (800 – 300 BCE) - History of Biology: abstract scientific thoughts to Greek philosophers - Written transcripts of lectures of learned men: Roman translators and scribes, Islamic translators and scribes, Christian monks and learned men - Greek philosophical inquiry resonated with the most important questions of human existence: What is Man? What is the world? - Knowledge is connected to the political powers of the time - Similar to ancient & indigenous people: use their experience, meditation, and learned intuition in trying to understand what they believe is the nature of things. - Healing & surgery, Medicine, astronomy, and engineering Aristotle - Curiosity about the natural world - most influential Greek thinker - Born on the end of Greek era - Student of Plato, teacher of Alexander the Great - philosopher whose works have been the backbone of philosophical studies from this era until the European Renaissance - first biologist in the Western tradition - Specialist: one who has a considerable body of experience in practical fieldwork (scientific knowledge) - Generalist: one who knows many different areas of study (generalist’s understanding) - Practived both specialist & generalist mode of study - Studies: levels of organization, systematics, reproduction, embryology - Observer of life: fishes - Defined a species: breeding particular plants/animals can breed & produce offspring = reproduce - species were fixed, immutable, and that they have always existed - Christian Philosophers: integrate Genesis to Aristotle (species as created by God) - Aristotelian thought was the dominant view for a millennium in the West - Aristotle’s “Great Chain of Being”, as a classification system, was the major organizing principle and foundation of the emerging science of biology until the 18th century. - Aristotelian worldview Medieval Europe and the Golden Age of the Islamic Civilization - feudal and hierarchical - production of food and goods that were used in the local communities - Knowledge: relegated to few who knew how to read and write - ruling class: the Monarchies and the Church were very powerful - Monastic schools: education, governance, and practical applications of astronomy and medicine - Church: territory & ideological influence, sole interpreter of Holy Texts, arbiter of the appropriate knowledge and use of knowledge - Outside of church: practical arts, metallurgy, navigation, agriculture, engineering - Near Eastern Culture Exposure: first to trade via the Silk Road, Crusades, colonial expansion - Combined knowledge of the Arabic, Byzantine, Persian, and Indian cultural traditions (Golden Age of Islamic Civilization in the 12th century onwards)  - Students of the 12th Century: a. Eager for knowledge b. Latin Classics c. Roman Law d. Works of Church Fathers e. Advanced scholars: Muslims of Islamic Civilization - great storehouses of knowledge -> traveled to Spain & Constantinople to obtain translations of Green manuscripts f. Scholars: renewed western knowledge of Greek science and philosophy, Arabic mathematics and medicine - Islamic scientists & mathematicians: criticisms of Greek assertions, refined theories of the classical philosophers to conform empirical information, modified Aristotelian ideas, invented Algebra & Trigonometry, improved Indian numeral system to include zero (Arabic number system) - University: open to scholars, for male feudal lords who can afford high fees but neither clerks/monks - New scholars: prayer & good work -> rational change The European Enlightenment: The hypothetico-deductive method and democratizing knowledge - Descartes: Cartesian metaphysics, the mechanistic worldview, the duality between matter and mind - understanding of mechanisms of living systems—very much independent of the need for spiritual and magical causes—unfolded into the one we accept today. - Methodological skepticisim: assumption of the existence of God - Experiments on Generations of Insects (Francesco Redi - late 17th century, court physician to Grand Duke of Tuscany): disprove spontaneous generation of living things - Theory on the Transmutation of Life (Lamarck, early 1800s): species change as individuals relate to environment - Actual, physical examination: a. Advances in optics - visualization and discovery of microscopic entities and paving the way for the study of anatomy in greater detail. b. Advances in chemistry - analytical studies of phlogiston (thenceforth purified to what we know now as oxygen gas) and to look into what was once thought of as a metaphysical vital substance that animated living organisms c. Proteins - enzymes Reductionist Science and the growth of Biology - 19th and 20th centuries - Scientific Method, with its materialist, mechanistic, and reductionist philosophy - The interdisciplinary field Environmental Science includes traditional science; combines in issues such as environmental ethics and social issues - Growth of the field of Biology (natural history before) = medicine, food, agriculture - Chemistry: X-ray crystallography (chemical composition of cells as an object of study - 16th to 17th century: different organisms in different environments, Darwin’s “Theory of Evolution” - 18th to 19th century: scientific expeditions by trained naturalists - Late 19th century: ecology  - Mid-20th century: matter & energy flows + ecology - 1960s-1970s: basis of systems ecology, circa - Carson’s The Silent Spring (1962) Limits of mechanistic and reductionist paradigms - Human senses: creation of tools - Energy: do work - Human and animal power: machines fueled by coal, petroleum, & electricity - Rational skepticism: scientific communities to abrogate models - Cartesian Framework: analytical power and focus; control conditions to maximize gains, tool for industrial and economic growth - Cartesian analytical framework: industrial practices - singular focus on desired outcomes has led to many unforeseen consequences to the environment and to human societies - utilitarian view of Nature that has led to the environmental crises that we experience today - Cartesian science: complex systems, behaviour of the whole could be analysed in terms of the properties of its parts - Systems science: living systems cannot be understood by analysis. The properties of the parts are not intrinsic properties - Reductionist science has given us the concepts and tools with which to analyze parts of the living system Biocultural Expressions: - diverse/different - changing - people in different places, tradition (culture) Biocultural: - human culture-nature interrelationship - linkage between and among biological, cultural, and linguistic aspects - Biocultural studies (in Anthropology) refers to influence of physical and social environment on human biology and well being; integration of methodically collated cultural data with biological and environmental data (Biocultural diversity = biodiversity) freedom of choice (participation) Biocultural Knowledge: - intimate knowledge of the interplay among elements in the local living systems (validated by indegenous knowledge systems and modern scientific methods) - rooted in natural environment and culture (values & norms) How ancestors understood living systems: - based on observations, scientific methods, graphical situation, close relationship with environment How our Ancestors understood Living Systems: - intimate knowledge of our environment, gained through systematic observations - knowledge shared and passed on to the the next generation for survival (orally, written, through experience by elders) - each has a role to play in the creation, recording, teaching of knowledge Examples: cuneiforms in clay tablets - sumerians papyrus scrolls - egyptians bamboo tablets - east asian wax tablets - romans parchment - europe paper - chinese PARADIGM SHIFTS: FROM ANTIQUITY TO RENAISSANCE - paradigm: framework of theories, methods, standards and guiding principles - mechanistic worldview (reductionist science) to systemic (holistic/integrative science) - reductionist: analysis of complex system into parts - growth of science: rise of scholars, inventions, and scientific discoveries Scientific method can mechanistic worldview & systemic work together? - systemic = bigger picture - case to case basis per problem 1. Copernican Revolution 2. Theory of Evolution by Natural Selection - "survival of the fit enough" > "survival of the fittest" 3. Germ Theory of Disease Indigenous Knowledge Systems and Practices (IKSP) - traditional knowledge (myths, legends, folklores) passed on across generations - products of careful and methodologically sound observations of the natural world (the ones you visually see) - tested & re-tested for many years for survival and well-being MODULE 2. LIVING SYSTEM FROM THE BIOLOGICAL PERSPECTIVE System - set of parts connected to one another to achieve a certain goal - Interacting or interdependent group of items forming a unified whole Characteristics of a Living System 1. Organized into hierarchy or complexity (progressive function/specialization) - Living systems have: lower level to higher levels of organization / emergent properties: (dynamic interactions and exchanges with the environment) - 7 Basic Functions that operate all levels(Transcending Factors) 1. Energetics 2. Behavior 3. Development/succession 4. Evolution 5. Diversity 6. Integration 7. Regulation  2. Open to systems with purposes and goals for stability and sustainability, operating on control feedback mechanisms (input & output) Types of Systems: have common principles, philosophies, theories A system consists of 3 things: 1. Elements or structures 2. Interconnections or interactions that hold elements together 3. Function or purpose that produces own pattern or behavior over time World Views on Living Systems: oral traditions -> written word Law of Specialization - The more highly adapted an organism is to a specific environment, the more difficult it is for the organism to adapt to a different environment When a living creature dies, it loses its “system-ness” according to Meadow (2008) (gone parts or no longer functioning) Biological Level of Organization 1. Atom - fundamental units of all substances, living or not 2. Molecules - only living things make the “molecules of life”: lipids, proteins, DNA, RNA, and complex carbohydrates 3. Organelles - membrane-enclosed structure 4. Cell - “basic unit of life”, live and reproduce independently 5. Tissues - organized cells 6. Organ - organized tissues that are carrying out specific tasks 7. Organ System - set of interacting organs 8. Organisms - made up of organ systems, can be unicellular or multicellular 9. Population - same type of species/individuals in a given area 10. Community - all populations in a given area 11. Ecosystem / Ecological system - community and non-living environment functioning together, 1st unit complete as it is necessary for survival 12. Biosphere / Ecosphere - encompasses all region’s of earth’s crust, waters, and atmosphere where organisms live 11 Ecological Levels of Organization of Living Systems (Biosystems): exists in physical space and time 1. Cell 2. Tissue 3. Organ 4. Organ system 5. Organism 6. Population 7. Community 8. Ecosystem 9. Landscape 10. Biome 11. Ecosphere Energetics: study involving energy and matter conversion, keep it stable Ecosystem Development/Succession: development at the level of the ecosystem Evolution: plays an important role in bringing about diversity Patterns of diversity can be seen at: 1. Genetic 2. Species 3. Ecosystem levels Integration and regulation: bring subsystems into a unified and stable unit Living systems are open systems with purposes and goals - it continues indefinitely within the natural cycles to attain sustainability Sun-driven Process of Photosynthesis - generates net increases in material quality on Earth - “open” system - Input: plants convert energy from sunlight -> chemical energy (as sugar) = work - Output: higher tropic levels (consumers) -> lost from the ecosystem as heat Cycling of Matter - Plants and animals = consumption - Breakdown of matter to elemental form, driven by microorganisms = decomposition - Making the living system a relatively closed system Sedimentation and Mineralization: unutilized decomposed materials become slowly deposited Slow geological cycles: volcanic eruptions and weathering Feedback Mechanism - keeping this cycle in control - Physiological regulation system in a living body to maintain internal state homeostasis 2 types of feedback: 1. Negative feedback - reduce excessive response 2. Positive feedback - happens when humans depart from this natural cycle POSITIVE (less) NEGATIVE (more) Result expansion/amplification Process is inhibited or of output slowed down Occurence Less frequent More frequent Effects on Stimulus Increases productivity by Decreases productivity by fostering stimulus reducing stimulus Stability Less stable More stable  Practical Examples Blood clotting, fruit Temperature regulation, ripening, childbirth in blood glucose level mammals, menstrual regulation cycle Tragedy of the commons: an economic theory related to sustainability - Commons: any shared and unregulated resource (water, fish stocks, trees, etc.) - Humans (society) fail due to greed or self-interest Negative feedback (natural cycle) - Increased population of grazers = increased grazing pressure on plants -> decreased plant quality and quantity Positive feedback (unregulated anthropological activity, raising & selling) - Increased population of grazers (to increase profit) = increased grazing pressure until nothing is left The natural system: can persist without humans Humans: cannot live without the natural system MODULE 3. LIVING SYSTEM FROM THE BIOLOGICAL PERSPECTIVE Living systems: dependent on a steady flow of energy Energy - ability to do work - motion, heat, and light MRS. CHEN 1. Mechanical / kenetic energy 2. Radiant energy: sun 3. Sound energy 4. Chemical energy 5. Heat energy 6. Electrical energy 7. Nuclear energy Energy can be possessed in two ways: 1. Mechanical / Kinetic energy 2. Potential / Stored energy Energy can be from sources like: 1. Renewable sources 2. Non-renewable sources - supply the bulk of our energy needs Laws of Thermodynamics - basis of the flow of energy - Field about heat, work, temperature, energy transfer 1st law: Law of Conservation of Energy (universal empirical observation) - The amount of energy in the universe: constant - Energy can be transformed but cannot be created nor destroyed - Energy cannot be changed without conversion to heat energy - Flow of energy is the essence of life 2nd law: Law of Entropy - Energy can flow - More use of energy = convert to heat (energy of random molecular motion) - More energy transfer = more energy loss - Disorder (entropy) in the universe is increasing - Energy is transformed and converted into heat (waste form: heat energy) - Decreased capacity of energy to do work = lower level of entropy - Energy flows: higher to lower levels Chemical Evolution: H2O is a good medium of chemical reactions Biomolecules: sustain/support life 4 types of biological macromolecules: 1. Lipids/fatty acids - E.g. phospholipid bi-layer - hydrophilic head, hydrophobic tail 2. Nucleic acids 3. Carbohydrates 4. Proteins Primary source of energy: sun In photosynthesis, only 2% of total light is used to make food, most are transformed as heat. Energy can be obtained by living things in 3 ways: 1. Photosynthesis 2. Chemosynthesis 3. eating/digesting other living/dead organisms by heterotrophs Trophs 1. Heterotrophs - eating/digesting other living or dead organisms - cannot capture light or chemical energy to make food - Rely on autotrophs 2. Photoautotrophs (algae, plants, photosynthetic bacteria) - harness radiant energy -> chemical energy in the form of ATPs (adenosine triphosphates) - Synthesize complex organic molecules: glucose 3. Autotrophs - foundation of Earth's ecosystems - Form base of food chains & food webs - Energy captured from light/chemicals: sustains all community organisms 4. Chemoautotrophs - create their organic food from inorganic chemicals - supply energy to ecosystem Trophic levels: feeding level in a food chain or food web - Primary producers - Primary consumers (herbivores) - Secondary consumers - Tertiary consumers Energy flows 1. Food chains 2. trophic levels 3. Dissipated as heat because organisms carry metabolic processes 10% of net energy production at 1 trophic level in passed on next trophic level - Processes: respiration, growth, and reproduction to reduce energy flow Nutritional quality of consumed material affects efficiency of energy flows Consumers: convert high-quality food sources-> new tissue Decomposers (more important than producers): process large amounts of organic material -> return nutrients to the ecosystem in inorganic form Ecological pyramids / Trophic pyramids: graphical representation to show relationships between energy and trophic levels in an ecosystem Pyramids 1. Biomass 2. Energy (Lindeman’s 10% regulation law) 3. Numbers  4. Parasitic Food Chain Most useful pyramid: pyramid of energy (shows relationship between energy and tropic level) Biological magnification or biomagnification: - important environmental consequence of increasing the concentration of persistent, toxic substances at each trophic level, from the primary producers to the different consumer levels. - many substances bioaccumulate like pesticide dichlorodiphenyltrichloroethane (DDT) Pesticides and toxic substances - Banned in the U.S. - Prevalent in the PH -> mussels Energy: flows in one direction through ecosystems - entering as sunlight and leaving as heat - Passed form 1 organism to another through food webs & food chains Matter: makes up living organisms is conserved and recycled Cycle: continual transformation process, return to original form Biogeochemical Cycle: - Geology and chemistry - These elements cycle at different timescales and extent through the biosphere, from one organism to another, and between the biotic and abiotic worlds. - recycling inorganic matter between living organisms and their environment - move chemicals through the biosphere - ensure the survival of various organisms - Can be influenced by humans (e.g. overuse of fertilizers, causing alterations in nitrogen cycle) 1. transfer molecules 2. storage of elements 3. functioning of ecosystems 4. link living organisms with abiotic factors 5. regulate the flow of substances Earth: a closed system for matter Matter: continually recycled on time scales Elements: critical components of life and must be available for biological processes, recycled & not replenished from outside sources Geological processes - Weathering and erosion: recycling of materials Radiant energy (photosynthesis & evaporation) - Drives cycle that involves reservoirs where chemicals are stored/concentrated for long periods 5 Most Common Elements that are Vital Components of Life 1. Hydrogen and oxygen (water) 2. Carbon 3. Nitrogen 4. Phosphorus Human activities influence biogeochemical cycles - Mined elements - Burnt fossil fuels - Clear areas of vegetation that store carbon - Overuse fertilizers because of runoff (altered nitrogen & phosphorus) Kinds of Cycles 1. Water Cycle 2. Oxygen Cycle 3. Carbon Cycle 4. Nitrogen Cycle 5. Phosphorus Cycle MODULE 4. CYCLES AND PATTERNS Cell - basic unit of life, smallest structure that exhibits almost all known properties/attributes of "being alive." Mitosis & Meiosis - reproduction and developmental processes Cell Theory - Cells arise from the division of pre-existing cells Cycle - series of events, repeated & same order, results in patterns Cell Cycle - series of events in a cell = cell growth & cell division SUMMARY Property Mitosis (body cells) Meiosis (sex cells) DNA Replication Interphase; before Interphase; before meiosis I mitosis begins begins No. of Divisions 1 (PMAT) 2 (PMAT) Synapsis of None Prophase I along with Homologous (maternal crossing over between & paternal) nonsister chromatids = chromosomes chiasmata that hold pairs together due to sister chromatid cohesion No. of daughter cells & 2 diploid (2n) cells; 4 haploid (n) cells; genetic composition Identical to parent cell Half as many chromosomes as parent cell yet different from parent cell  Role in animal body Multicellular adult to rise Gametes; reduces half of from zygote the no. of chromosomes & genetic variability in Cell growth gametes Cell repair Asexual reproduction Parts of a Chromosome Chromosome arm Centromere If 2: sister chromatids DNA Molecules thread-like structures in the nucleus (animal & plant cells) Made of: protein & DNA Carries genomic/genetic information from cell to cell Cell Cycle and DNA Replication Cell Division Important process among living organisms Allows growth, renewal/replacement of damaged/old body cells 24hr cell cycle: 1. Mitosis – 1 hour 2. Interphase – 95% of the cycle; cell growth & DNA replication Complex Eukaryotic Cell Cycle Phase Features Gap 0 (G0) No cell division & chromosomes in chromatin state that is made of DNA wrapping histone proteins Gap 1 (G1) Increased cell size for preparation (11 hours) Synthesis (S) DNA replication (8 hours) Gap 2 (G2) Protein synthesis & microtubule formation (4 hours) Mitosis (M) Nuclear and cytoplasmic division (1 hours) The Stages of Mitosis (in body cells) 1. Prophase 2. Prometaphase 3. Metaphase 4. Anaphase 5. Telophase 6. Cytokinesis (underway late telophase) Cleavage Furrow in animal cells – occurs after chromosomes have been segregated during anaphase where chromosomes are moving to opposite poles (involved in Cyntokinesis) Cell Plate Formation in plant cells – in mitosis telophase The Stages of Meiosis (in sex cells) 1. Meiosis I: 1st cell division, homologous chromosomes separate 2. Meiosis I = 2 haploid (n) daughter cells with replicated chromosomes (reductional division) 3. Meiosis II: 2nd cell division, sister chromatids separate 4. Meiosis II = 4 haploid (n) daughter cells with unreplicated chromosomes (equational division) Meiosis I Division in 4 Phases: (PMAT) Prophase I Metaphase I Anaphase I Telophase I & cytokinesis Cell Cycle Control System - sequential events of the cell cycle Regulated by both internal and external controls Clock has specific checkpoints where the cell cycle stops until a g-ahead signal is received Checkpoints: G1 checkpoint - most important checkpoint in many cells Go-signal in G1 checkpoint = complete S, G2, M phases and divide No go-signal in G1 checkpoint = exit cycle, switch to G0 phase (nondividing state) The Cell Cycle Clock: Cyclins and Cyclin-Dependent Kinases Regulatory proteins: cyclins and cyclin-dependent kinases (Cdks) Activity of these regulatory proteins fluctuates during the cell cycle MPF (maturation-promoting factor) - cyclin-Cdk complex: triggers a cell’s passage past the G2 checkpoint into the M phase Life Cycle - series of stages (form & function) an organism passes through Reproductive Cycles - happens in eukaryotic cells (with nucleus) 3 Reproductive Cycles in Eukaryotes 1. Haplontic / zygotic Meiosis Zygote (2n) undergoes meiosis = haploid (n) cells: “spores” Haploid cell: independent functioning organism E.g. Chlamydomonas - unicellular green alga 2. Diplontic Organism (2n) gets ½ from mother & father (23 pairs of chromosomes - 2n=46), meiosis for gamete formation Gametes: only haploid (n) cells Gametes uninte to form diploid (2n) zygote (Mitosis = fully functional multicellular organism) Meiosis: particular tissues, produce haploid gametes, cycle goes on E.g. Humans, most plants & animals Involves spermatogenesis, oogenesis, and fertilization Angiosperm life cycle is part of this 3. Diplohaplontic / alteration of generation Multicellular sporophyte (2n) & gametophyte (n) in algae, protists, fungi, and primitive plants Can be: macroscopic or microscopic Gametophytes releases tiny individual cells by Mitosis = acts as gametes (n) Gametes fuse together from a zygote Sporophyte: specific tissues undergo meiosis = haploid (n) gametes (“spores”) Spore that divides into many cells, produces gametophyte E.g. archegoniosphore & antheridiosphote in liverworts, fern Angiosperm Life Cycle - plants that bear flowers, development of functional gamtes allows successful reproduction Predominant plants Grasses (Rice) Domesticated vegetables Male Parts of a Flower 1. Stamen a. Anther -> pollen sacs (house pollen grains; 1 pollen grain contains sperm nuclei & tube nucleus that develop through microsporogenesis) b. Filament Female Parts of a Flower 1. Carpel (pistil) a. Stigma b. Style c. Ovary (contains ovules - has female megagametophyte) Megasporogenesis produces 8 nuclei: 1. Egg nucleus 2. Fused polar nuclei 3. Synergids 4. antipodals Reproductive Process and Patterns 1. Apomixis in plants gamete doubles in choromosome number -> seed formation from maternal tissues of ovule (no meiosis & fertilization) Asexual seed formation Greek: apo (away) & mixis (fusion) 2. Parthenogenesis in animals Unfertilized egg develops into a mature organism E.g. male bee from haploid egg cells (egg cells may also be fertilized and develop into mature organisms), Komodo dragon, Daphnia (sons and daughters) 3. Hermaphroditism in animals Organism has male & female reproductive system (sperm & egg production) No self-fertilization, mating is required Mostly for organisms in deep soil or mud or some parasities Opposite sex difficult to find = male & female reproductive tissues evolved E.g. earthworm hermaphrodite receives functional sperm cells from a male only one gonad produces a functional gamete. In persons born with such conditions in humans, both reproductive tissues are nonfunctional 4. Sex Reversal in animals Fish & oysters in response to environment Females (ovary = egg cells) & males (testis = sperm cells) Sequential hermaphroditism In response to environment, protandrous species are born as male, become females Protogyny: female first, male later Parthenogenesis, Hermaphroditism, Sex Reversal: Seasonal and hormonal cues control these patterns. They are often linked to favorable environmental conditions or energy supplies. Sexual Reproduction innate characteristic of animals to pass on genes to the next generation, promote variability and avoid extinction common during courtship and mating behavior in animals. Courtship and mating ensure the success of sexual reproduction, e.g., sperm and egg production can be triggered by sexual displays, rituals, and courtship behavior. Gametophyte – haploid stage that produces gametes Sporophyte – diploid stage that produces spores Pattern formation in animal development variations in life cycles and developmental patterns differential expression of genes in specific cells and tissues expression of homeobox genes in insects. Social organizations/ Social Insects social organization: family, club, barangay leader and members animals like social insects behave more efficiently in gathering food than we humans a. assume roles and follow the rules b. cooperate for survival c. E.g. phenomenon of eusociality Humans study complex systems like the bee colony and other social animals to understand the interactions that evolved in these systems all learn from nature Social interactions: may affect the way genes behave or become expressed Genes: may affect certain behaviors that determine an organism's success in life and survival via adaptations army ants - established models for social evolution and behavioral genetics, among others. MODULE 5. POPULATION DYNAMICS Population Total of individuals Same species Within a geographic area Life table or Mortality table Record of birth and death rates Survivorship Curve Graphical presentation of the elements of life table Age Structure “Groufie” of a population at a specific moment in time Members are clustered: age & sex categories Population Density Number of individuals divided by the size of the area Fertility Rate - 2.2 Life Expectancy 73.3 - both sexes 76.0 - females 70.7 - males Infant Mortality Rate & Deaths of Children under 5 Years Old 26.9 - infant mortality 36.0 - deaths under age 5 World Urban Population - 57.5% Median Age - 30.6 years old World Population by Region - Asia (top 1) World Population Density - more on India, Philippines, Indonesia, China, Japan World’s Prevailing Religion - Christianity World Population by Country - India (top 1) Principle of Population (Thomas Malthus Essay: 1798) 1. Exponential model a. 1st principle b. Any species can increase in number c. Environment is constant 2. Population Dynamics a. Results to density (adding & removing individuals) 3. Populations grow logistically under ideal environment conditions and resource dependent (constant supply) Logistic Model (Pierre Francois Verhulst - 1838) Rate of reproduction is proportional to both the existing population and the amount of available resources, all else being equal Predator Interaction (Alfred Lotka & Vito Volterra) Effect of another population Prey: an animal taken by a predator as food Predator: obtains food by killing & consuming another organism Demographic Factors Enter system: birth & immigration -> increase population size Exit system: death & emigration -> decrease population size Population Growth growth of a population without environmental resistance factors Carrying Capacity: total number of individuals that the environment can support Logistic growth model: when resources get diminished, population growth rate will ultimately plateau Exponential vs Logistic Growth Model Environmental Resistance Factors Limits population growth Examples: ○ Availability of raw materials ○ Availability of energy ○ Availability of space ○ Interactions among organisms ○ accumulation of waste products and their means of disposal Population Regulation Environmental checks & limits population growth 1. Density-dependent factors - Effect on birth & death increase as population increases (directly proportional) - E.g. biotic factors: parasitism, disease, predation, competition 2. Density-independent factors - Same influence on population (small/big size) - E.g. abiotic factors: temperature, weather, light (natural disaster & unusual weather) MODULE 6. POPULATION CHANGES OVER TIME IN LIVING SYSTEMS Charles Darwin - presence of variation Autosomes - numbered chromosomes Sex chromosomes - 1 pair, XX OR XY Albinism Albus (latin ) - white Reduced pigmentation (Inherited disorder) Mutated tyrosinase gene on Chromosome 11q14 for melanin synthesis (TYR) by base substitution Single gene pair controls the trait (Two recessive alleles aa) 2 alleles: ○ Dominant allele A ○ Recessive allele a ○ Homozygous dominant (AA) - Two dominant alleles ○ Heterozygous dominant (Aa) - Dominant and recessive allele Polydactyly Conditions of having extra digits Homozygous dominant (PP) / heterozygous dominant (Pp) = condition Homozygous recessive (pp) = normal Baldness Higher in males than females (due to difference in testosterone levels) Males: BB or Bb = condition, bb = normal Females: BB = condition, Bb or bb = normal Trait is sex-influenced Population’s Gene Pool Consider all genes in every individual in a population  Assumptions met = Hardy-Weinberg equilibrium At Hardy=Weinberg equilibrium = easy determination of allele frequency once genotypic frequencies are known Very rare to find a real population with this Mutations & Immigrants Bring novel variations or genes into the population’s gene pool while emigrants remove genes from the gene pool