Chapter 1 Outline.pdf

Chapter 1 Outline 1.1: The Characteristics of Life 1. Biology is the study of all living organisms and their environments. a. All living organisms (1) are organized, (2) acquire materials and energy, (3) are homeostatic, (4) respond to stimuli, (5) reproduce and have p...

Chapter 1 Outline 1.1: The Characteristics of Life 1. Biology is the study of all living organisms and their environments. a. All living organisms (1) are organized, (2) acquire materials and energy, (3) are homeostatic, (4) respond to stimuli, (5) reproduce and have potential for growth, and (6) have an evolutionary history. Life is Organized 1. All organisms are made up of cells, the most basic building block of life. a. Organisms can be multicellular (composed of different types of cells) or single celled. b. Cells can be broken down into molecules and then further into atoms. 2. Groups of similar cells form tissues, which then form organs, then organ systems. An organism is a collection of organ systems. 3. A group of interbreeding organisms forms a species. All the species in a particular location form a population. Interactions between populations form a community. Communities interactions with their environments form ecosystems. The earth’s biosphere is made up of all its ecosystems. Life Requires Materials and Energy 1. No organism can survive without outside sources of energy, the capacity to do work. a. Animals acquire energy by eating food. 2. Food provides nutrient molecules, which are the building blocks of energy. a. Some molecules are broken down completely to provide energy to convert other molecules into parts and products of cells.  i. Metabolism is the sum of all these different chemical reactions (ex. The breakdown of food). 3. The sun is the main source of energy for the majority of life on Earth, such as plants, algae, and some bacteria. a. These organisms use photosynthesis to take the sun’s energy and convert it to chemical energy. This produces organic molecules that serve as the basis of the food chain. Living Organisms Maintain an Internal Environment 1. Homeostasis is the maintenance of an organism’s constant internal environment. This is crucial to the survival of the organism. 2. Body temperature plays a key role in homeostasis. a. Humans fluctuate between 36. 5 and 37.5 degrees C (97.7 and 99.5 degrees F) with the peak occurring at around 6 pm-10pm and the pit at around 2 am-4 am. b. Activity or lack thereof can also be a factor. i. Inactivity lowers, activity raises. c. A number of systems (including cardiovascular and nervous) work together to maintain a constant temperature (necessary for life). d. Also depends on external temperature. Body will shiver when cold, sweat when hot, but too high or too low is deadly. 3. Many systems work as one big system with the common purpose of maintaining homeostasis. a. Digestive system takes in nutrients. b. Respiratory exchanges gas w/ environment.  c. Cardiovascular system distributes nutrients/oxygen to cells, picks up their wastes. d. Metabolic waste products are excreted in the urinary system. e. Nervous and endocrine systems manage the functions of these other systems. Living Organisms Respond 1. Body’s ability to respond to stimuli (both internal and external) is vital to homeostasis. a. External response is more apparent since it involves movement, such as when one pulls their hand from a hot stove. b. Sensory receptors also detect internal environments. i. Ex. When startled, the heartbeat increases, which causes blood pressure to increase. If BP gets too high, the brain will increase blood vessels to restore normal BP. 2. All Life responds to stimuli, often by movement. a. Organisms use many mechanisms to move, but movement depends on the nervous and musculoskeletal systems of the particular organism. i. Plants track the sun and move face toward it. ii. In animals, whether movement is self-directed or a stimulus response, it constitutes behavior. 1. Behavior helps with food and reproduction. Living Organisms Reproduce and Develop 1. All living organisms are results of reproduction, the passing down of genetic information to the next generation; all living things have parents and no cell can be created if not from another cell.  a. Following fertilization, an egg forms into a zygote and undergoes a rapid period of development and growth, a part of development that involves increase in size and number of cells. b. Development refers to all changes from the time of fertilization until death, as well as the repair that takes place after an injury. 2. Deoxyribonucleic acid (DNA) contains all hereditary information that directs structure and function of all cells. a. DNA forms groups of genes, hereditary material with specific information for specific traits. b. An exact copy of each gene may be passed down to offspring. i. In humans, sperm and eggs contribute to direct growth and development so that the offspring resemble the parents. c. Sometimes, mutations occur so an organism can be better suited to its environment (evolution). Organisms Have an Evolutionary History 1. Evolution is the process by which a species changes over time (occurs in natural selection). a. Adaptation happens when a new mutation allows certain members of a species to gather new resources. These organisms are able to reproduce more, eventually phasing out those who lack said mutation. i. Ex. Those living on the Tibetan Plateau (4,000 m/14,000 ft) adapted a reduced amount of hemoglobin, the blood’s oxygen-carrying pigment. 2. Evolution is a constant throughout all life and future life. 1.2 Humans Are Related to Other Animals 1. All life on earth can be divided into three categories or domains 2. The three domains are Bacteria, Archaea, and Eukarya. a. Bacteria and Archaea contain prokaryotes (single celled, lack nucleus) b. Eukaryotic cells have a nucleus; can be single celled or multicellular 3. Initially eukaryotes were divided into four kingdoms, but new research suggests otherwise. a. Not all protists (earliest eukaryotes) share the same evolutionary lineage, meaning eukaryotes have evolved over several different paths. b. Scientists created six supergroups to explain these relationships, which is always being updated (so far, we believe that animals belong in the same supergroup [Opisthokonta] as fungi). 4. The four kingdoms are still widely used in classification, and they go as follows: a. Kingdom Protista, contains protists: i. Can be single-celled, with a few multicellular exceptions. ii. Some use photosynthesis, others find their own food. iii. Extremely diverse kingdom, meaning they don’t all share the same background and thus don’t belong to the same supergroup. b. Kingdom Plantae, contains plants: i. Multicellular, photosynthetic c. Kingdom fungi, contains fungi: i. Molds and mushrooms that help with decomposition. ii. Can be parasitic or photosynthetic.  d. Kingdom Animalia, contains animals: 5. Among the animals are vertebrates and invertebrates a. Only a few are vertebrates, meaning they have a spinal cord protected by a vertebral column (ex. Fish, reptiles, birds). i. Vertebrates with fur and mammary glands are mammals. b. The majority are invertebrates, so they lack a backbone (ex. Worms, insects, mollusks). 6. Humans are primates, most closely related to apes, but with a few key differences: a. Our developed brains, upright stance, creative language, and use of a far wider variety of tools b. We did not evolve from apes; they are our evolutionary cousins, sharing a common ancestor. If we had evolved from them, we wouldn’t both exist at the same time. Humans Have a Cultural Heritage 1. Humans also have a cultural heritage, which exists outside of their biological heritage. a. We communicate symbolically through language. b. Born without knowledge on how to behave, but learn through imitation and role models (mostly parents). c. Things like values, beliefs, and information are passed down from one generation to the next. d. We pass down the use of tools, but we have become so dependent on tools that we often forget we are part of the animal world around us. Humans Are Members of the Biosphere 1. Although humans are largely self sufficient, we still rely on the environment around us. a. Ex. We rely on microorganisms to decompose our waste and bacteria to clean up pollutants. 2. We rely on the environment to take care of us, even in our everyday lives. a. Rivers and lakes provide water for irrigation and drinking, as well as fish to eat. b. Prescription drugs were derived from naturally occurring plants. c. Forests can hold water to prevent flooding; they can also retain soil to prevent erosion.