Introduction: Evolution and the Foundations of Biology 1 Introduction: Evolution and the Foundations of Biology

Overview: Inquiring About Life An organism’s adaptations (fit) to its environment are the result of evolution For example, a beach mouse’s light, dappled fur acts as camouflage, allowing the mouse to blend into its surroundings Inland mice of the same species are darker in color, matching their surroundings Evolution is the process of change that has transformed life on Earth © 2016 Pearson Education, Inc. 2

Concept 1.1: The study of life reveals common themes Biology: study (ology) of living things (bios) To organize and make sense of all the information encountered in biology, focus on a few big ideas These 5 unifying themes help to organize biological information: Organization Information Energy and Matter Interactions Evolution © 2016 Pearson Education, Inc. 3

Figure 1.3 Theme: Emergent Properties at Successive Levels of Biological Organization 4 Tissues 10 The Biosphere 9 Ecosystems 5 Organs 8 Communities 3 Cells 1 Mole- cules Figure 1.3 Exploring levels of biological organization 6 Organ- isms 2 Organell-es 7 Populations © 2016 Pearson Education, Inc.

Emergent Properties All living things are complex and highly ordered Each level builds in complexity on the levels below it With each step becoming more complex, new properties emerge that were not previously present Called emergent properties : “an organism is a living whole greater than the sum of its parts” E.g. if the brain is injured, the whole organism will be affected, not just the brain © 2016 Pearson Education, Inc. 5

Structure and Function At each level of the biological hierarchy we find a correlation between structure and function Analyzing a biological structure can give clues about what it does and how it works “Form Fits Function” © 2016 Pearson Education, Inc. 6

The Cell: An Organism’s Basic Unit of Structure and Function Cell: lowest level capable of performing all activities of life All living organisms are made of cells: bounded by a plasma membrane (cell membrane) and cytoplasm Unicellular: bacteria, protists Multicellular: plants, fungi, animals The 2 main forms of cells are prokaryotic and eukaryotic © 2016 Pearson Education, Inc. 7

Prokaryotic cells: lack a nucleus or other membrane-bound organelles Primitive, oldest cells Found in domains Bacteria and Archae Smaller on size Contains loose DNA (not in a nucleus) All have tough external walls Eukaryotic cell: contains membrane-enclosed nucleus (with DNA) & membrane-enclosed organelles Newer cells Found in domain Eukarya Larger cells Not all eukaryotes have a cell wall Plants have a cell wall Animals do not © 2016 Pearson Education, Inc. 8

Life’s Processes Involve the Expression and Transmission of Genetic Information DNA (deoxyribonucleic acid) is packaged in the form of chromosomes © 2016 Pearson Education, Inc. 9

DNA, the Genetic Material A DNA molecule holds hundreds or thousands of genes, each a stretch of DNA along the chromosome Genes are the units of inheritance that transmit information from parents to offspring As cells grow and divide, the genetic information encoded by DNA directs their development © 2016 Pearson Education, Inc. 10

DNA molecule: 2 long strands in a double helix Figure 1.7 Nucleus A DNA C Nucleotide T Cell A DNA molecule: 2 long strands in a double helix Each link: 1 of 4 kinds of chemical building blocks called nucleotides, abbreviated A, T, C, and G T A C C G T Figure 1.7 DNA: The genetic material A G T A (a) DNA double helix (b) Single strand of DNA © 2016 Pearson Education, Inc.

DNA is blueprint for making proteins, which build & maintain a cell Figure 1.8 (b) A lens cell uses information in DNA to make crystallin proteins. Crystallin gene (a) Lens cells are tightly packed with transparent proteins called crystallin. Lens cell A C C A A A C C G A G T DNA T G G T T T G G C T C A DNA is blueprint for making proteins, which build & maintain a cell Genes/DNA--RNA-- protein Gene expression is the process of converting information from gene to cellular product/protein TRANSCRIPTION mRNA U G G U U U G G C U C A TRANSLATION Chain of amino acids Figure 1.8 Gene expression: Cells use information encoded in a gene to synthesize a functional protein PROTEIN FOLDING Protein Crystallin protein © 2016 Pearson Education, Inc.

Genomics: Large-Scale Analysis of DNA Sequences An organism’s genome is its entire set of genetic instructions Genomics is the study of sets of genes within and between species Proteomics refers to the study of sets of proteins and their properties The entire set of proteins expressed by a cell or group of cells is called a proteome © 2016 Pearson Education, Inc. 13

Life Requires the Transfer and Transformation of Energy and Matter What makes life possible? Input of energy, mainly from the sun Transformation of energy from one form to another Plants/other photosynthetic organisms convert the energy of sunlight into the chemical energy of sugars The chemical energy of these producers is then passed to consumers that feed on the producers © 2016 Pearson Education, Inc. 14

Organisms Interact with Other Organisms and the Physical Environment Every organism interacts with other organisms and with physical factors in its environment Both organisms and their environments are affected by the interactions between them Interactions between organisms include those that benefit both organisms and those in which both organisms are harmed Interactions affect individual organisms and the way that populations evolve over time © 2016 Pearson Education, Inc. 15

ENERGY FLOW Chemicals pass to organisms that eat the plants. I C A L C Figure 1.9 ENERGY FLOW Chemicals pass to organisms that eat the plants. I C A L C Y H E M C L I N C G Light energy comes from the sun. Plants convert sunlight to chemical energy. Heat is lost from the ecosystem. Organisms use chemical energy to do work. Plants take up chemicals from the soil and air. Decomposers return chemicals to the soil. Figure 1.9 Energy flow and chemical cycling Chemicals © 2016 Pearson Education, Inc.

Scientists calculate that the CO2 that human activities have added to the atmosphere has increased the average temperature of the planet by 1°C since 1900 Climate change is a directional change in global climate that lasts three decades or more Climate change has already affected organisms and their habitats all over the planet © 2016 Pearson Education, Inc. 17

The Core Theme: Evolution accounts for the unity and diversity of life Evolution makes sense of everything we know about living organisms Evolution explains patterns of unity and diversity in living organisms Similar traits among organisms are explained by descent from common ancestors Differences among organisms are explained by the accumulation of heritable changes © 2016 Pearson Education, Inc. 18

Classifying the Diversity of Life Taxonomy: branch of biology that identifies, names, and classifies organisms; 8 taxons Ranked from most general to most specific Domain….Kingdom….Phylum….Class…..Order……Family….Genus…..Species © 2016 Pearson Education, Inc. 19

Domains Bacteria and Archaea: unicellular prokaryotes 3 Domain System: Domains Bacteria and Archaea: unicellular prokaryotes Domain Eukarya includes all eukaryotic organisms Domain Eukarya: 1 unicellular eukaryotic group: Protista & 3 multicellular eukaryotic kingdoms: Plantae: produce their own food by photosynthesis Fungi: absorb nutrients Animalia: ingest their food © 2016 Pearson Education, Inc. 20

(a) Domain Bacteria (b) Domain Archaea 2 m 2 m (c) Domain Eukarya Figure 1.12 (a) Domain Bacteria (b) Domain Archaea 2 m 2 m (c) Domain Eukarya Kingdom Animalia 100 m Figure 1.12 The three domains of life Kingdom Plantae Kingdom Fungi Protists © 2016 Pearson Education, Inc.

Unity in the Diversity of Life A striking unity underlies the diversity of life Universal genetic code: All living things need DNA to reproduce All DNA has same 4 nitrogenous bases; A, T, C and G Similarities of cell structure Flagella of protozoa (protist) and mammalian sperm Cilia of paramecium (protist) and cilia in human lungs © 2016 Pearson Education, Inc. 22

Charles Darwin and the Theory of Natural Selection Charles Darwin published On the Origin of Species by Means of Natural Selection in 1859 Darwin made two main points Species showed evidence of “descent with modification” from common ancestors Natural selection is the mechanism behind “descent with modification” Darwin’s theory captured the duality of unity and diversity © 2016 Pearson Education, Inc. 23

Figure 1.14 Charles Darwin as a young man © 2016 Pearson Education, Inc.

European robin American flamingo Gentoo penguin Figure 1.15 Figure 1.15 Unity and diversity among birds © 2016 Pearson Education, Inc.

Species generally suit their environment Darwin observed that Individuals in a population vary in their traits, many of which are heritable More offspring are produced than survive, and competition is inevitable Species generally suit their environment Darwin inferred that Individuals that are best suited to their environment are more likely to survive and reproduce Over time, more individuals in a population will have the advantageous traits © 2016 Pearson Education, Inc. 26

Darwin called this process natural selection Figure 1.16-s4 In other words, the environment “selects” for the propagation of beneficial traits Darwin called this process natural selection Population with varied inherited traits Elimination of individuals with certain traits Reproduction of survivors Increased frequency of traits that enhance survival Figure 1.16-s4 Natural selection (step 4) © 2016 Pearson Education, Inc.

The Tree of Life The forelimb of a human, foreleg of a horse, flipper of a whale, and wing of a bat all share a common skeletal architecture The shared anatomy of mammalian limbs reflects inheritance of a limb structure from a common ancestor (Homology) The diversity of mammalian limbs results from modification by natural selection over millions of years Darwin proposed that natural selection could cause an ancestral species to give rise to two or more descendent species For example, the finch species of the Galápagos Islands are descended from a common ancestor © 2016 Pearson Education, Inc. 28

Figure 1.17 Green warbler finch Certhidea olivacea (insect-eater) Vegetarian finch Platyspiza crassirostris (fruit-eater) ANCESTRAL FINCH Woodpecker finch Camarhynchus pallidus (insect-eater) Evolutionary relationships are illustrated with treelike diagrams that show ancestors and their descendants Small tree finch Camarhynchus parvulus (insect-eater) Common cactus finch Geospiza scandens (cactus-eater) Figure 1.17 Descent with modification: finches on the Galápagos Islands Large ground finch Geospiza magnirostris (seed-eater) © 2016 Pearson Education, Inc.

In studying nature, scientists form and test hypotheses Science: means “to know” Inquiry: the search for information and explanation Involves the hypothetico-deductive reasoning Biology begins with careful observations Recorded observations are called data Data fall into two categories Qualitative data, or descriptions rather than measurements i.e.Jane Goodall’s observations of chimpanzee behavior Quantitative data, or recorded measurements, which are sometimes organized into tables and graphs © 2016 Pearson Education, Inc. 30

Figure 1.18 Figure 1.18 Jane Goodall collecting qualitative data on chimpanzee behavior © 2016 Pearson Education, Inc.

Inductive reasoning: used to develop a hypothesis What is a hypothesis? An educated guess Go from a large number of specific observations to general conclusions i.e.“all organisms are made of cells” :based on two centuries of microscopic observations Hypothesis leads to predictions that can be tested with additional observations or an experiment An experiment is a scientific test, often carried out under controlled conditions © 2016 Pearson Education, Inc. 32

Deductive Reasoning Deductive reasoning: used to make predictions Go from general premises to specific predictions The hypothesis is then tested experimentally A hypothesis can never be conclusively proven to be true because we can never test all the alternatives Hypotheses gain credibility by surviving multiple attempts at falsification, while alternative hypotheses are eliminated by testing A hypothesis must be testable and falsifiable For example, hypotheses involving supernatural explanations cannot be tested © 2016 Pearson Education, Inc. 33

The initial observations may lead to multiple hypotheses to be tested For example Observation: Your desk lamp doesn’t work Question: Why doesn’t your lamp work? Hypothesis 1: The bulb is burnt out Hypothesis 2: The lamp is broken Both these hypotheses are testable © 2016 Pearson Education, Inc. 34

FORMING AND TESTING HYPOTHESES Figure 1.19 EXPLORATION AND DISCOVERY FORMING AND TESTING HYPOTHESES SOCIETAL BENEFITS AND OUTCOMES COMMUNITY ANALYSIS AND FEEDBACK Figure 1.19 The process of science: a realistic model © 2016 Pearson Education, Inc.

Experimental Variables and Controls A controlled experiment compares an experimental group (the non-camouflaged mice) with a control group (the camouflaged mice) The factor that is manipulated and the effect of the factor on the system are both experimental variables The factor manipulated by the researchers—color—is called the independent variable The effect of the manipulated factor—amount of predation—is called the dependent variable Researchers usually control unwanted variables by canceling them out using control groups © 2016 Pearson Education, Inc. 36

Theories in Science In the context of science, a theory is Broader in scope than a hypothesis General enough to lead to new testable hypotheses Supported by a large body of evidence in comparison to a hypothesis Theory is the highest honor that can be given to any piece of information in science Cell Theory Theory of Evolution Big Bang Theory Wave Theory of Light © 2016 Pearson Education, Inc. 37