Biology Tenth Edition - Topic 1: A View of Life PDF

BIOLOGY tenth edition Topic 1 A View of Life © Cengage Learning 2015 SOLOMON MARTIN MARTIN BERG  A View of Life Biology is the science of life – Biologists constantly acquire new knowledge...

BIOLOGY tenth edition Topic 1 A View of Life © Cengage Learning 2015 SOLOMON MARTIN MARTIN BERG  A View of Life Biology is the science of life – Biologists constantly acquire new knowledge that gives insight to discoveries about millions of organisms on Earth © Cengage Learning 2015  Neural stem cells in the brain. Neural stem cells (green) in the hippocampus gather around a neuron (purple). Neural stem cells appear to receive and respond to signals transmitted from one neuron to another. © Cengage Learning 2015  1.1 Major Themes of Biology Five major themes of biology – Biological systems interact – Structure and function are inter-related – Information must be transferred – Life depends on a continuous input and transfer of energy – Populations change over time through the process of evolution © Cengage Learning 2015  Major Themes of Biology (cont’d.) Biological systems interact – Every organism is a biological system that is interdependent with many other biological systems Structure and function are inter-related – Example: both horses and wolves have teeth, but the horse’s teeth are designed to grind vegetation, whereas the wolf’s canine teeth are designed to tear meat © Cengage Learning 2015  Major Themes of Biology (cont’d.) Information must be transferred – Must be transmitted within cells, among cells, among organisms, and from one generation to the next Life depends on a continuous input and transfer of energy – All living cells and organisms require energy from the sun to live © Cengage Learning 2015  Major Themes of Biology (cont’d.) Populations change over time through the process of evolution – Evolution explains how the ancestry of organisms can be traced back to earlier forms of life © Cengage Learning 2015  1.2 Characteristics of Life All organisms – Are composed of cells – Grow and develop – Regulate their metabolic processes – Respond to stimuli – Reproduce – Adapt to the environment © Cengage Learning 2015  Organisms are Composed of Cells Every living organism is composed of one or more cells – New cells are formed only by division of previously existing cells – Unicellular life-forms: consist of a single cell – Multicellular organisms: depend on coordinated functions of cells organized to form tissues, organs, and organ systems © Cengage Learning 2015  Organisms are Composed of Cells (cont’d.) Plasma membrane: protects the cell and regulates passage of materials between the cell and its environment Specialized molecules, such as DNA: contain genetic instructions and transmit genetic information Organelles: internal structures of cells that are specialized to perform specific functions © Cengage Learning 2015  Organisms are Composed of Cells (cont’d.) Prokaryotic cells – Exclusive to bacteria and Archaea – Structurally simple: do not have a nucleus or other membrane-bound organelles Eukaryotic cells – Typically contain a variety of organelles enclosed by membranes, including a nucleus, which houses DNA © Cengage Learning 2015  Organisms Grow and Develop Biological growth is defined by: – An increase in size of individual cells of an organism, in number of cells or in both Development is defined by: – All changes that occur during an organism’s life © Cengage Learning 2015  Organisms Regulate Their Metabolic Processes Metabolism includes all chemical activities that take place in an organism, including: – Chemical reactions essential to nutrition – Growth and repair – Conversion of energy Homeostatic mechanisms carefully regulate metabolic processes to maintain an appropriate, balanced internal environment © Cengage Learning 2015  Organisms Respond to Stimuli Stimuli: physical or chemical changes in the external or internal environment that cause movement Complex animals have highly specialized cells that respond to specific types of stimuli, such as light Plants respond to light, gravity, water, touch, and other stimuli © Cengage Learning 2015  Organisms Respond to Stimuli (cont’d.) © Cengage Learning 2015  Figure 1-3 Plants respond to stimuli (a) When hairs on the leaf surface of the Venus fly trap (Dionaea muscipula) detect the touch of an insect, the leaf responds by folding. (b) The edges of the leaf come together and interlock, preventing the fly’s escape. The leaf then secretes enzymes that kill and digest the insect. © Cengage Learning 2015 © Cengage Learning 2015  Organisms Reproduce Asexual Sexual – Variation occurs – Fusion of egg and only by mutations sperm © Cengage Learning 2015  Figure 1-4 Asexual and sexual reproduction (a) Asexual reproduction. One individual gives rise to two or more offspring that are similar to the parent. Difugia, a unicellular amoeba, is shown dividing to form two amoebas. (b) Sexual reproduction. Typically, each of two parents contributes a gamete (sperm or egg). Gametes fuse to produce the offspring, which has a combination of the traits of both parents. A pair of tropical flies is shown mating. © Cengage Learning 2015  Populations Evolve and Become Adapted to the Environment Adaptations: – Inherited characteristics that enhance the ability to survival in a particular environment – May be structural, physiological, biochemical, behavioral or a combination of all four © Cengage Learning 2015  Figure 1-5 Adaptations These Burchell’s zebras (Equus burchelli), photographed in Tanzania, are behaviorally adapted to position themselves to watch for lions and other predators. Stripes are thought to be an adaptation for visual protection against predators. They serve as camouflage or to break up form when spotted from a distance. The zebra stomach is adapted for feeding on coarse grass passed over by other grazers, an adaptation that helps the animal survive when food is scarce. Discussion question: What characteristics of certain animals do you think are an adaptation for survival? © Cengage Learning 2015  1.3 Levels of Biological Organization Reductionism: we learn about a structure by studying all its parts – Each level has its own emergent properties, or characteristics, not found at a lower level – Example: we can study individual neurons in isolation, but still not understand the full function of the brain © Cengage Learning 2015  Organisms Have Several Levels of Organization Atoms and molecules form cells Cells associate to form tissues Tissues organize into functional structures called organs In animals, major biological functions are performed by an organ system Organ systems function together to make up a complex, multicellular organism © Cengage Learning 2015 © Cengage Learning 2015  Several Levels of Ecological Organization Can Be Identified Population – All members of one species living in the same geographic area at the same time Community – Populations of various organisms living and interacting in a particular area Ecosystem – A community together with its nonliving environment © Cengage Learning 2015  Levels of Organization (cont'd.) Biosphere – All of Earth’s ecosystems together Ecology – The study of how organisms relate to one another and to their physical environment © Cengage Learning 2015  1.4 Information Transfer Biological systems receive and respond to information and store information Organisms inherit the information they need to grow, develop, carry on self- regulated metabolism, respond to stimuli, and reproduce © Cengage Learning 2015  DNA Transmits Information from One Generation to the Next DNA: a molecule that makes up genes – Two chains of atoms in a twisted helix – Each chain contains a sequence of chemical subunits called nucleotides – Four types of nucleotides – Each sequence of three nucleotides is part of the genetic code Transmits genetic information from generation to generation © Cengage Learning 2015  Information is Transmitted by Chemical and Electrical Signals Genes control development and function of every organism DNA genes contains instructions for making all the proteins required by the organism Proteins are large molecules important in determining the structure and function of cells and tissues © Cengage Learning 2015  Communication Between Cells Takes place through proteins and other molecules – Hormones: signal cells in distant organs to secrete a required substance or change a metabolic activity – Animals’ nervous systems transmit information through neurotransmitters, electrical impulses, and chemical compounds © Cengage Learning 2015  Communication Between Organisms Takes place through the release of chemicals, visual displays and sounds – Organisms can often combine several signals together – Many animals perform complex courtship rituals in which they display parts of their bodies to attract a mate © Cengage Learning 2015  1.5 The Energy of Life All life processes require a continuous input of energy Organisms can neither create energy nor use it with complete efficiency Whenever energy is used, some energy is converted to heat and dispersed into the environment © Cengage Learning 2015  The Energy of Life (cont'd.) A self-sufficient ecosystem includes producers, consumers, and decomposers – Autotrophs produce their own food, usually through photosynthesis – Heterotrophs consume producers – Bacteria and fungi break down all non-living organic material © Cengage Learning 2015  Photosynthesis The chemical process that utilizes carbon dioxide, water and light energy to synthesize glucose, the food energy used by autotrophs – Oxygen is released as a by-product carbon dioxide + water + light energy ➔ glucose + oxygen © Cengage Learning 2015  Cellular Respiration Process of capturing energy released by nutrient molecules through a series of carefully regulated chemical reactions – Cells use this energy to do work, including synthesis of new cell components glucose + oxygen ➔ carbon dioxide + water + energy © Cengage Learning 2015  Energy in Heat Light Ecosystems energy Heat Heat Food Producer Primary (plant) consumer (caterpillar) Secondary consumer (bird) Plant litter, Dead wastes bodies Decomposers (bacteria, fungi) © Cengage Learning 2015 Soil  Figure 1-9 Energy flow through the biosphere Continuous energy input from the sun operates the biosphere. During photosynthesis, producers use the energy from sunlight to make complex molecules from carbon dioxide and water. Primary consumers, such as the caterpillar shown here, obtain energy, nutrients, and other required materials when they eat producers. Secondary consumers, such as the bird, obtain energy, nutrients, and other required materials when they eat primary consumers that have eaten producers. Decomposers obtain their energy and nutrients by breaking down wastes and dead organic material. During every energy transaction, some energy is lost to biological systems, dispersing into the environment as heat. Discussion Question: How does air pollution caused by human activity affect the balance of energy flow through the biosphere? © Cengage Learning 2015  1.6 Evolution: The Basic Unifying Concept of Biology Evolution is the process by which populations of organisms change over time – Involves passing genes for new traits from one generation to another © Cengage Learning 2015  Biologists Use a Binomial System for Naming Organisms Systematics: study of the diversity of organisms and their evolutionary relationships Taxonomy: a subspecialty of systematics; the science of naming and classifying organisms In the 18th century, Carolus Linnaeus developed a hierarchical system of naming and classifying organisms © Cengage Learning 2015  Carl Linnaeus 1707-1778 © Cengage Learning 2015  Species and Genus Species: a group of organisms with similar structure, function and behavior – Capable of breeding with one another – Population with a common gene pool and shared ancestry Closely related species are grouped into a genus (genera) © Cengage Learning 2015  Binomial System The Linnaean system: binomial system of nomenclature because each species has a two-part name: – First part: genus – Second part: the specific epithet; designates a particular species in that genus – Example: Canis familiaris, the domestic dog, and Canis lupus, the timber wolf © Cengage Learning 2015  Taxonomic Classification is Hierarchical Related genera are grouped in a family Families are grouped into orders, orders into classes, and classes into phyla (phylum) Phyla are assigned to kingdoms, and kingdoms are grouped in domains Each level is a taxon (taxa) © Cengage Learning 2015 © Cengage Learning 2015  Tree of Life: Three Domains and Several Kingdoms Cladogram: branching diagram showing proposed evolutionary relationships among organisms and fossil evidence – Clade: a group of organisms with a common ancestor – Most biologists assign organisms to three domains and several kingdoms or clades © Cengage Learning 2015  Domain Bacteria Domain Archaea Domain Eukarya Bacteria Archaea Protists Plants Animals Fungi Common ancestor of © Cengage Learning 2015 all organisms  Figure 1-11 A survey of the three domains of life Biologists assign organisms to three domains and to several kingdoms and other groups. The protists do not form a clade and are no longer considered a kingdom. They are assigned to several groups (not shown). Discussion Question: Why are the protists no longer considered a kingdom? a) These large, rodshaped bacteria (Bacillus anthracis) cause anthrax, a disease of cattle and sheep that can infect humans. (b) These archaea (Methanosarcina mazei ) produce methane. (c) These unicellular protozoa (Tetrahymena) are classied in one of the many protist clades. (d) Plants include many beautiful and diverse forms, such as the lady’s slipper (Phragmipedium caricinum). (e) Among the ercest animals, lions (Panthera leo) are also among the most sociable. The largest of the big cats, lions live in prides (groups). (f) Mushrooms, such as these y agaric mushrooms (Amanita muscaria), are fungi. The fly agaric is poisonous. © Cengage Learning 2015  Species Adapt in Response to Changes in Their Environment Every organism is the product of interactions between environmental conditions and genes inherited from its ancestors – Organisms must adapt to changes in the environment for survival – These evolutionary processes take place over time and involve many generations © Cengage Learning 2015  Natural Selection: An Important Evolutionary Mechanism Natural selection: proposed by Charles Darwin and Alfred Wallace – Darwin’s book, On the Origin of Species by Natural Selection (1859), proposes that present forms of life descended, with modifications, from previously existing forms © Cengage Learning 2015  Darwin’s Four Observations Individual members of a species vary from one another Organisms produce many more offspring than will survive to reproduce Organisms must compete for resources Survivors pass their adaptations for survival on to their offspring; the best adapted individuals of a population produce more offspring © Cengage Learning 2015 © Cengage Learning 2015  Organisms Produce More Offspring Than Can Survive Certain traits of each individual contribute to the probability for success in its environment © Cengage Learning 2015  Figure 1-12 Egg masses of the wood frog (Rana sylvatica) Many more eggs are produced than can develop into adult frogs. Random events are largely responsible for determining which of these developing frogs will hatch, reach adulthood, and reproduce. However, certain traits of each organism also contribute to the probability for success in its environment. Not all organisms are as prolific as the frog, but the generalization that more organisms are produced than survive is true throughout the living world. © Cengage Learning 2015  Mutation and Variation Most variations among individuals result from different varieties of genes that code for each characteristic Random mutations: source of variations; chemical or physical changes in DNA that can be inherited Mutations modify genes and provide the raw material for evolution © Cengage Learning 2015  Populations Evolve as a Result of Change Gene pool: all the genes in a population (a reservoir of genetic variation) – Natural selection acts on individuals within a population – Selection favors individuals with genes for traits that allow them to respond effectively to environmental pressure – Over time, members of a population become better adapted to their environment and less like their ancestors © Cengage Learning 2015  Populations Evolve (cont'd.) a b c © Cengage Learning 2015  Figure 1-13 Adaptation and diversification in Hawaiian honeycreepers All three species shown here are endangered, mainly because their habitats have been destroyed by humans or species introduced by humans (a) The bill of this ‘Akiapola’au male (Hemignathus munroi ) is adapted for extracting insect larvae from bark. The lower mandible (jaw) is used to peck at and pull off bark, whereas the maxilla (upper jaw) and tongue remove the prey. (b) ‘I’iwi (Vestiaria cocciniea) in ‘ohi’a blossoms. The bill is adapted for feeding on nectar in tubular owers. (c) Palila (Loxiodes bailleui ) in mamane tree. This finch-billed honeycreeper feeds on immature seeds in pods of the mamane tree. It also eats insects, berries, and young leaves. © Cengage Learning 2015 © Cengage Learning 2015  1.7 The Process of Science Science is a way of thinking, and a method of investigating, the natural world in a systematic manner The scientific method: – A series of steps in which scientists make observations, ask questions, develop hypotheses, test those ideas with experiments, gather and analyze data, and then draw a conclusion from that data © Cengage Learning 2015  Science Requires Systematic Thought Processes Science is systematic, with standard rules and procedures Science requires rigorous methods to examine a problem – Deductive reasoning: begins with supplied information (premises) and draws conclusions based on that information – Inductive reasoning: begins with specific observations and draws a conclusion or general principle © Cengage Learning 2015  Careful Observations and Chance When a blue mold invaded one of his bacterial cultures, Alexander Fleming noticed that the contaminated area was surrounded by a zone where bacteria did not grow Fleming did not set out to discover penicillin in 1928, but as a scientist, he was prepared to make observations and formulate critical questions © Cengage Learning 2015 A Hypothesis is a Testable Statement Hypothesis: a tentative explanation for observations or phenomena – Reasonably consistent with well-established facts – Capable of being tested; and test results should be repeatable by independent observers – Falsifiable (can be proven false) © Cengage Learning 2015 A Hypothesis is a Testable Statement (cont’d.) A falsifiable hypothesis can be tested – If no evidence is found to support it, the hypothesis is rejected – Models are used to develop/test hypotheses Provide a comprehensive explanation for a large number of observations – Many hypotheses can be tested by experiment Control groups vs. experimental groups © Cengage Learning 2015  Researchers Must Avoid Bias Example: in a double-blind study neither patient nor physician knows who gets an experimental drug and who gets a placebo Not all experiments can be so neatly designed – it is often difficult to establish appropriate controls © Cengage Learning 2015  Scientists Interpret Results and Make Conclusions Scientists gather data in an experiment, interpret their results, and then draw conclusions from them – Even results that do not support the hypothesis may be valuable and may lead to new hypotheses Sampling error can lead to inaccurate conclusions Experiments must be repeatable © Cengage Learning 2015  Scientists Interpret Results and Make Conclusions (cont’d.) Curtain Curtain Marbles Marbles Single selection Multiple selections produces produces Assumption Assumption Actual ratio 100% blue Actual ratio 30% blue 20% blue 20% blue 70% white 80% white 80% white a b © Cengage Learning 2015  Figure 1-18 Statistical probability (a) Taking a single selection can result in sampling error. If the only marble selected is blue, we might assume all the marbles are blue. (b) The greater the number of selections we take of an unknown, the more likely we can make valid assumptions about it. © Cengage Learning 2015  A Theory is Supported by Tested Hypotheses Scientific theory: – An integrated explanation of some aspect of the natural world, based on a number of hypotheses, each supported by consistent results from many observations or experiments – By showing relationships among classes of facts, a scientific theory clarifies our understanding of the natural world © Cengage Learning 2015  Many Hypotheses Can’t be Tested by Direct Experiment Indirect evidence of early evolution: – Fossils of the simplest organisms are found in the oldest strata (rock layers), and increasingly complex organisms in more recent strata – Physical and molecular similarities between organisms – Studies of ongoing evolutionary processes in the laboratory or in the field © Cengage Learning 2015  Paradigm Shifts Allow New Discoveries Paradigm: a set of assumptions or concepts that constitute a way of thinking about reality – As new facts are discovered, biologists have to make paradigm shifts – they change their view of reality to accommodate new knowledge © Cengage Learning 2015  Systems Biology Integrates Different Levels of Information Systems (integrative) biology: develops large data sets with mathematics, statistics and engineering principles © Cengage Learning 2015  Science Has Ethical Dimensions Science depends on truthfulness and the ability to communicate results Scientists: – Face many societal and political issues in the 21st century Example: human genome research – Must be responsible for educating the public about their work © Cengage Learning 2015