Origin of Life PDF

ORIGIN Characteristi OF cs of Life Body and Ecological Organizatio  At the end of the lesson the student should be able to: 1. Explain the evolving concept of life based on emerging pieces of evidence. 2. Describe how unifying themes (e.g structure...

ORIGIN Characteristi OF cs of Life Body and Ecological Organizatio  At the end of the lesson the student should be able to: 1. Explain the evolving concept of life based on emerging pieces of evidence. 2. Describe how unifying themes (e.g structure and function,  EARTH’S EARLY ATMOSPHERE 4.6 Billion Years Old Geologic evidence shows Earth formed 4.6 BYA Early Atmosphere Probably contained CO₂, CO, Nitrogen, Ammonia, Methane But, No Oxygen! (wouldn’t support life) 3.8 BYA Earth cooled enough for liquid water to form I. Early Theory a. Spontaneous Generation (Abiogenesis)- The hypothesis that life arises regularly from non-living thing II. Experiments That Helped to Disprove Spontaneous Generation a. Italian physician and poet, Francesco Redi (1668) 1. Hypothesis: Maggots arose from tiny, non-visible eggs laid on meat 2. Procedures: a. Put pieces of meat in several jars, leaving half open to the air b. Cover the other half with thin gauze to prevent entrance of flies 3. Results: a. After a few days, meat in all jars spoiled and maggots were found only on the meat in the uncovered jars b. One of the first documented experiments to use a control! II. Experiments That Helped to Disprove Spontaneous Generation cont. a. French scientist, Louis Pasteur (1859) The French Academy of Sciences held a contest for the best experiment either proving or disproving spontaneous generation 1. Hypothesis: Microorganisms do not arise from meat broth 2. Procedures: a. Place meat broth in a flask with a long, curved neck. (This permitted air to enter, but trapped dust and other airborne particles) b. Boil the flask thoroughly to kill any microorganisms c. Do NOT seal the open end of the flask d. Wait an entire year before gathering results Results: a. After a year, no microorganisms could be found in the broth! b) Pasteur then removed the curved neck, permitting dust and other particles to enter. In just one day, the flask contained microorganisms! c) Microorganisms had clearly entered the flask with the dust particles from the air III. Theories Explaining the Formation of Life a. The Formation of Complex Molecules: the Miller/Urey Experiment (1953) 1. Miller and Urey simulated the conditions of Earth’s early atmosphere and oceans, adding energy to simulate the lightning that was believed to be commonplace 2. After one week, 10-15% of the carbon had turned into organic compounds, and 2% of the carbon had created amino acids, the building blocks of proteins/life III. Theories Explaining the Formation of Life cont. B. Molecules from Space 1. Many of the compounds produced by the Miller/Urey experiment are known to exist in space. 2. If these compounds can survive the harshness of space, perhaps they were present when earth initially formed. 3. Organic molecules could have also been brought to earth by space debris. IV. Current Theories a. The Formation of Complex Molecules 1. Collections of these molecules tend to gather together into tiny round droplets known as coacervates a. In the laboratory, these droplets have been shown to grow and divide! b. Coacervates are not living cells, but their existence suggests ways in which the first cell may have formed. c. Early oceans are the perfect environment for coacervates – warm, wet, large, and the water “protected” their delicate structure Figure 16.9 IV. Current Theories B. The First True Cells 1. They were prokaryotic (lacked nucleus), anaerobic (survived in absence of O₂), heterotrophs that resemble types of bacteria alive today 2. Found in rock 3.5 billion years old IV. Current Theories C. The Evolution of Photosynthesis 1. Early heterotrophic bacteria fed on organic molecules, releasing CO₂ as a waste product. 2. 3.5 billion years ago, photosynthesis evolved that was mostly anaerobic, releasing sulfur as a waste product. 3. Natural selection favored organisms that could harness energy from the Living readily available sun stromatolite 4. 2.7 billion years ago, photosynthesis s still exist that used sunlight and released in Shark Bay, oxygen as a waste product Australia developed. Commonly used in cyanobacteria (which produce fossils called stromatolites) V. The Road to Modern Organisms A. Oxygen and Life 1. Oxygen began to increase in the atmosphere about 2.3 bya 2. Oxygen was poisonous to early anaerobic organisms and many either died off or remained underground/underwater. Earth was transformed! Anaerobic bacteria such as these now live only deep within the ocean , deep in mud and in other places where the atmosphere does not h Organisms using Oxygen began to evolve and dominate the planet! V. The Road to Modern Organisms B. Eukaryotes and the Origin of Complex Cells 1. Eukaryotic organisms with a true nucleus, DNA and membrane- bound organelles evolved between 1.4 and 1.6 bya 1. Eukaryotes likely evolved because of endosymbiosis – one bacterium engulfing another and passing that structure on 2. For example, the modern chloroplast is the descendent of an engulfed cyanobacteria! V. The Road to Modern Organisms C. Sexual Reproduction and Multicellular Life 1. Multi-celled organisms are thought to have evolved when single- celled organisms stacked together to share the duties of life 2. The origin of sexual reproduction rapidly increased the rate of early evolution 3. Genes and traits began shuffling and combining in ways they were not capable of before 4. Genetic variation created new species under the influence of natural selection! Characteristics of Life  Biology = the study of life What does it mean to be alive??? There are 8 characteristics of life... No single characteristic is enough to describe a living thing... They must have all eight.  8 Characteristics of Life 1. Living things are made up cells. 2. Living things reproduce. 3. Living things are based on a universal genetic code (DNA). 4. Living things grow and develop.  8 Characteristics of Life (cont.) 1. Living things obtain and use materials and energy. 2. Living things respond to their environment. 3. Living things maintain a stable internal environment. (homeostasis) 4. Taken as a group, living things change over time.  1—Made up of cells They can be either unicellular or multicellular. ***Unicellular = made up of ONE cell Picture of a unicellular organism. Picture of a Cell ***Multi-cellular = made up of MORE than one cell Picture of multicellular organisms  2—Reproduction There are 2 types of reproduction: 1. Asexual 2. Sexual ***asexual = reproduction ***sexual = reproduction that requires ONE parent that requires TWO parents 3—Based on a genetic code ***DNA = DNA is the genetic code found in every cell. DNA is inherited from parents and controls your traits.  4—Grow and Develop **All living things grow ***Think about it... Do and develop during at you look the same as least part of their life. when you were born???? 5—Need for materials and energy **Living things need a constant supply of materials and energy. **Metabolism = the process of using those materials.  6—Response to the environment **Organisms detect and respond to STIMULI (or signals) from their environment. **Internal stimuli = signal comes from **External stimuli = inside the organism signal comes from outside the organism 7—Maintaining internal balance Despite changing conditions around them, organism must keep their internal conditions stable/balanced. **Homeostasis = the process of keeping the internal environment stable/balance/constant  8—Change over time Over hundreds, thousands, and millions of years, organisms have the potential to change = evolution Organization & Body Systems  Anatomy & Physiology The study of the human body Anatomy is concerned with the structure of a part Physiology is concerned with the function of the part  Levels of Organization Body is organized into levels from most simple to most complex  Atoms Most simple Compose all substances Chemicals elements Molecules Atoms joined together form molecules Example: amino acids  Macromolecules Molecules joined together form macromolecules Example: protein  Organelles Tiny structures found in cells that perform cellular functions Example: mitochondria – supplies cell with energy  Cells Macromolecules found in all cells Basic unit of all living things  Tissue Composed of similar types of cells and performs a specific function Example: blood, muscle, fat  Organs Groups of tissues working together to perform a specific function Example: heart, stomach Organ System Groups of organs that perform a particular function Example: digestive system: supply body with the nutrients needed for growth and repair  Organism All the body systems make up an organism Unicellular organism: made up of one cell Example: amoeba Multicellular organism: made up of many cells Example: gorillas  Review 1. ________ is concerned with the structure or an organ or part, while ________ is concerned with the function. 1. ___________ are groups of tissues working together to perform a specific function. 3. ______________ organisms are made up of many cells, while ___________ organisms are made up of one cell. 4. Basic unit of all living things are called ________.  Introduction Organs in the body work together in systems 11 organ systems in the body Organ systems can be divided into 4 categories based on function  Body Systems Support, Integration & Maintenance Reproduction & Movement, Coordination Development of the Body & Protection Support, Movement, & Protection Integumentary System: Organs: skin and accessory organs (hair & nails) Function: protects tissue, regulate body temperature & contains sense organs Skeletal System Organs: bones, cartilage, & ligaments Function: protects body parts, produce blood cells, stores calcium & phosphorus salts Muscular System Organs: skeletal, cardiac, and smooth muscles Function: move voluntarily, respond to stimuli, produce body heat  Integration & Coordination Nervous System Organs: brain, spinal cord & nerves Function: conducts nerve impulses from the sense organs to the brain and then to the muscles and gland Endocrine System: Organs: Hypothalamus, pituitary, thyroid, parathyroid, adrenals, pancreas, ovaries, testes Function: secretes chemicals that are messengers between body part, maintain proper functioning of reproductive system Maintenance of Body Circulatory (Cardiovascular) system: Organs: Heart, blood vessels, blood Function: transports nutrients and oxygen to cells through blood, removes wastes Immune (Lymphatic) System: Organs: Lymph nodes, thymus, spleen Function: protects body from disease Respiratory System: Organs: Nose, pharynx, larynx, trachea, lungs Function: bring oxygen into lungs and take carbon dioxide out of the lungs Digestive System: Organs: mouth, pharynx, esophagus, stomach, small & large intestine, rectum Function: receive food and digest into nutrient molecules Urinary System: Organs: kidneys and urinary bladder Function: gets rid of nitrogenous wastes, helps regulate fluid level and chemical content of the blood  Reproduction & Development Reproductive System: Organs: Male: testes, epididymis, vas deferens, urethra, penis Female: ovaries, Fallopian tubes, vagina, uterus Function: produce sex cells, nourish and protect fetus (female) Level of Organization of an Ecosystem  Biosphere contains the combined portions of the planet in which all of life exist, including land, water and atmosphere  Species Species - group of organisms so similar to another that they can breed and produce fertile offspring  Population Population – same species and live in same area  Community Communities – different populations that live together in a defined area  Ecosystem Ecosystem – a collection of all organisms that live in a particular place together with their nonliving environment. What shapes an Ecosystem?  Biotic and Abiotic Biotic and Abiotic factors determine the survival and growth of an organism and the productivity of the ecosystem in which an organism lives.  Biotic Factors Living Factors that influence an ecosystem Plant life Animal life  Abiotic Factors Physical, non-living factors that influence an ecosystem Examples- temperature, precipitation, humidity, wind, nutrients, sunlight  Other factors that affect an Ecosystem The area where an A niche is the full organism lives is range of physical and called its habitat. biological conditions in which an organism Habitats provide lives and the way in populations of which the organism wildlife with food, uses those water, shelter and conditions. It is an space. organisms’ occupation.  Biome Biome – a group of ecosystems that have the same climate and similar dominant communities. 13.1 Ecologists Study Relationships KEY CONCEPT Ecology is the study of the relationships among organisms and their environment. 13.1 Ecologists Study Relationships Ecologists study environments at different levels of organization. Ecology is the study of the interactions among living things, and between living things and their surroundings. An ______is an individual living thing, such as an alligator. A __________is a group of the same species that lives in one area. A ___________ is a group of different species that live together in one area. An ________ includes all of the organisms as well as the climate, soil, water, rocks and other nonliving things in a given area. A ________ is a major regional or global community of organisms characterized by the climate conditions and plant communities that thrive there.