Chapter 1 Biology - A View of Life PDF

Because learning changes everything. ® Biology Sylvia S. Mader...

Because learning changes everything. ® Biology Sylvia S. Mader Michael Windelspecht Chapter 1 A View of Life Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC.  Outlin e 1.1 The Characteristics of Life 1.2 Evolution and the Classification of Life 1.3 The Process of Science 1.4 Challenges Facing Science  1.1 How to Define Life Biology is the scientific study of life. Around 8.7 M species excluding bacteria. There is great diversity among living things. Living things: – are composed of the same chemical elements as nonliving things. – obey the same physical and chemical laws that govern everything in the universe. 3  Diversity of Life Simple Microscopic bacteria More Complex organisms Despite diversity, all living things share the same basic characteristics. 4  How to define life? Living Things: - Life is organized. The cell is the basic unit. - Requires materials and energy. - Maintain homeostasis. - Respond to stimulus. - Reproduce and develop - Have adaptations  1.1 Characteristics of Life 1. Living things are organized. The levels of biological organization range from atoms to the biosphere. The cell is the basic unit of structure and function of all living things.  Living things can be Unicellular or multicellular Each level of organization is more complex than the level preceding it.  As biological complexity increases, each level acquires new emergent properties that are determined by the interactions between the individuals parts. 6  Levels of Biological Organization (1) Atom Smallest unit of an element composed of electrons, protons, and neutrons Basic unit of matter  Levels of Biological Organization (2) Molecule Union of two or more atoms of the same or different elements  Atom Smallest unit of an element composed of electrons, protons, and neutrons  Levels of Biological Organization (3) The smallest and most basic unit of life Cell The structural and functional unit of all living things  Molecule Union of two or more atoms of the same or different elements Atom Smallest unit of an element composed of electrons, protons, and neutrons  Levels of Biological Organization (4) Tissue A group of cells with a common structure and function  Cell The structural and functional unit of all living things  Molecule Union of two or more atoms of the same or different elements  Atom Smallest unit of an element composed of electrons, protons, and neutrons  Levels of Biological Organization (5) Organ Composed of tissues functioning together for a specific task  Tissue A group of cells with a common structure and function  Cell The structural and functional unit of all living things  Molecule Union of two or more atoms of the same or different elements  Atom Smallest unit of an element composed of electrons, protons, and neutrons  Levels of Biological Organization (6) Organ System Composed of several organs working together  Organ Composed of tissues functioning together for a specific task  Tissue A group of cells with a common structure and function  Cell The structural and functional unit of all living things  Molecule Union of two or more atoms of the same or different elements  Atom Smallest unit of an element composed of electrons, protons, and neutrons  Levels of Biological Organism Organization (7) An individual; complex individuals contain organ systems  Organ System Composed of several organs working together  Organ Composed of tissues functioning together for a specific task  Tissue A group of cells with a common structure and function  Cell The structural and functional unit of all living things  Molecule Union of two or more atoms of the same or different elements  Atom Smallest unit of an element composed of electrons, protons, and neutrons  Species A group of similar, interbreeding organisms  Organism An individual; complex individuals contain organ systems  Organ system Composed of several organs working together  Organ Composed of tissues functioning together for a specific task  Tissue A group of cells with a common structure and function Cell The structural and functional unit of all living organisms  Molecule Union of two or more atoms of the same or different elements  Atom Smallest unit of an element composed of electrons, protons, and neutrons  The Complex Organization of Living Things What If the level of CO2 changes!!! Basic unit of matter 2. Living things require materials and energy. Food provides nutrients, which is used either as building blocks or for energy. Energy is the ability to do work.  Energy is required to maintain organization of the cell & conduct life-sustaining processes such as chemical reactions. Metabolism is all the chemical reactions that occur in a cell.  The SUN is the ultimate source of energy for nearly all life on Earth. Plants & algae capture solar energy & perform photosynthesis. Photosynthesis is a process that converts solar energy into the chemical energy of carbohydrates. 17  Ecosystems Ecosystems are characterized by chemical cycling and energy flow. Chemicals are not used up when organisms die. Chemicals move from one population to another in a food chain. Chemicals move from producers to consumers to decomposers. As a result of death and decomposition, inorganic molecules are returned to producers to use them again. Energy from the sun flows through plants and other members of the food chain as one population feeds on another. Therefore, there must be a constant input of solar energy. Energy flows & nutrients cycle in an ecosystem  Living things acquire materials and energy Ultimate source of Chemical energy Energy Solar Energy Photosynthesis Food (nutrients) Building blocks Energy- capacity to do work Metabolism- all chemical reactions in cell  3. Living things maintain homeostasis. Homeostasis is the maintenance of balanced internal conditions within certain boundaries.  Ability to maintain a state of biological balance.  Feedback systems monitor internal conditions and make adjustments without the need for any conscious activity. * The nervous system and endocrine system are important in maintaining homeostasis. 21  Ex: negative feedback: To maintain body temperature Control center sends data to directs response control center 98.6°F set point to stimulus Sensor Effect Blood vessels dilate; sweat glands secrete. negative feedback stimulus and return to normal temperature above n ormal Normal body temperature below norma l negative feedback stimulus and return to normal Effect Sensor Blood vessels constrict; sweat glands are inactive; shivering may occur. Control center directs response to stimulus Body temperature homeostasis. sends data to control center 98.6°F set point  4. Living things respond to stimuli. Living things interact with the environment & respond to changes in the environment.  The ability to respond often produces movement. - unicellular organisms: - beating of microscopic hairs - movement toward or away from chemicals or light Ex: Paramecium moves towards warm & acid water (seeking bacteria) - multicellular organisms: - leaves of plants turns toward the sun - monarch butterfly flying south on the approach of fall 23 5. Living things reproduce and develop. Life comes from life. All living organisms must reproduce to maintain a population. The manner of reproduction varies among different organisms. When organisms reproduce, they pass on copies of their genetic information (genes) to the next generation.  Genes determine the characteristics of an organism.  Genes are composed of DNA (deoxyribonucleic acid). 24  Living things reproduce and develop 1- Asexual: 2- Sexual: Bacteria, Protista and in multicellular other unicellular organisms organisms Genes contain information on how organisms are to be ordered Chromosomes Cell DNA 6. Living things have adaptations. - An adaptation is any modification that makes an organism better an organism better able to function in a particular environment. Ex. Penguins: Lives in Antarctica, have stubby, flattened wings suitable for swimming. An extra layer of fat (blubber) to keep them warm. - The diversity of life exists because over long periods of time, organisms respond to ever changing environments by developing new adaptations. - Evolution is the change in a population of organisms over time to become more suited to the environment. 26  1.2 Evolution & the Classification of Life The theory of evolution explains the diversity and unity of life. – Organisms are diverse in form, function & life style, but they all made of cells, have same genetic, same metabolic rxns, acquire energy etc…. – The theory of evolution suggests how all living things descended from a common ancestor. – “Common descent with modification” 27  Natural Selection by Charles Darwin Natural selection is an evolutionary mechanism that makes modifications (adaptations) possible. The environment selects which traits are more apt to be passed on to the next generation. Selective agents can be biotic or abiotic agents. – Individuals with the favorable traits produce the greater number of offspring that survive and reproduce. – Increases the frequency of those traits in population Mutations fuel natural selection. – Introduce variations among members of a population 28 A plant species that generally have smooth leaves has undergone a mutation and some leaves are hairy Some plants within a population exhibit variation in leaf structure. Deer prefer a diet of smooth leaves over hairy leaves. Plants with hairy leaves reproduce more than other plants in the population. Generations later, most plants within the population have hairy leaves, as smooth leaves are selected against.  Organizing Diversity Taxonomy is the discipline of biology that identifies, names, and classifies organisms according to certain rules. Systematics is the study of evolutionary relationships between organisms. Evolutionary tree is like a family tree. Classification categories From least inclusive category (species) to most inclusive category (domain): Species, genus, family, order, class, phylum, kingdom, and domain Each successive category above species includes more types of organisms than the preceding one. How Living Things Are Classified? Most inclusive Scientific name: ex: Homo sapiens Universal, Binomial, Latin based  Evolutionary Tree of Life An evolutionary tree traces the ancestry of life on Earth to a common ancestor. Prokaryotes are structurally simple but metabolically complex 32  Three Domains 1. Domain Bacteria, unicellular Prokaryotes – Contains unicellular prokaryotes that live in all environments including our skin, mouth & gut. 2. Domain Archaea, unicellular Prokaryotes – Live in extreme environments. They organize their DNA different from bacteria. Their cell walls & membranes are more similar to eukaryotes than to bacteria. 3. Domain Eukarya: Protists, Fungi, Plantae, Animalia – Contains unicellular and multicellular eukaryotes Eukaryotes contain a membrane-bound nucleus. 33 34  Domain Bacteria Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Prokaryotic cells of various shapes Adaptations to all environments Absorb, photosynthesize, or chemosynthesize food Unique chemical characteristics Escherichia coli, a bacterium 6,600x © A.B. Dowsett/SPL/Science Source 35 Domain Eukarya Consists of four kingdoms 36  1.4 The Process of Science The scientific method is a standard series of steps used by scientists in order to gain new knowledge that is widely accepted among scientists. – The scientific method can be divided into four steps: Observation Hypothesis Predictions & Experiments Data Collection with Statistical Analysis Conclusion 37  The Scientific Method 1. Observation Scientists use their senses to gather information about a phenomenon or natural event. They use instruments to aid them. Literature review. 2. Hypothesis A hypothesis is a tentative or possible explanation of what was observed. It is developed through inductive reasoning by using creative thinking to combine isolated facts into a cohesive whole. It is testable 38  The Scientific Method 3. Prediction & Experiments Experiment is a series of procedures designed to test a hypothesis. It uses deductive reasoning “IF, then” logic. Scientist predicts an expected outcome. A test group is exposed to the experimental variable (Independent variable) A control group goes through all aspects of the experiment but is not exposed to the experimental variable. The data are the results of an experiment (dependent variable). Model, organisms used to test hypothesis. 39  The Scientific Method 4- Data collection with statistical analysis Data= results are presented in tables or graphs. Graphs= X-axis for experimental variable. Y- axis for results Statistics = help in analyzing & evaluating the data. Standard error or standard deviation: How far off the average is the data ? Statistical significance, Probability value (P) what is the probability that the results are due to chance or any other factor & not due to the experimental variable? » Less than 5% is acceptable (p