1 A View of Life Chapter 1: pp

Warm-Up Question What is the definition of the word life?

3 1.1 Defining Life Living organisms can be Microscopic: Bacteria Paramecium Living organisms can be Macroscopic (Multi-cellular): Snow goose Humans Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (Bacteria): © Dr. Dennis Kunkel/Phototake; (Paramecium): © M. Abbey/Visuals Unlimited; (Morel): © Royalty-Free Corbis; (Sunflower): © Photodisc Green/Getty Images; (Snow goose): © Charles Bush Photography BacteriaParameciumMorelSunflowerSnow goose

4 1.1 Defining Life Living things:  All made of chemical elements  All are organized: atoms → molecules → cells  Cells (Unicellular or Multi-cellular). The basic structural and functional unit of all living things Cells are produced from preexisting cells Cells are the smallest units to perform all vital physiological functions

Levels of Biological Organization Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 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 Biosphere Regions of the Earth’s crust, waters, and atmosphere inhabited by living things Ecosystem A community plus the physical environment Community Interacting populations in a particular area Population Organisms of the same species in a particular area Organism An individual; complex individuals contain organ systems Organ System Composed of several organs working together

6 A. LT are Organized Each level of organization builds on the previous Acquires emergent properties: Interactions between the parts making up the whole All emergent properties follow the laws of physics and chemistry

7 B. Living Things: Acquire & Process Food LT maintain organization with energy and nutrients Metabolism is all the chemical reactions that occur in a cell or in an organism. The sun is the ultimate source of energy Homeostasis - Maintenance of internal conditions within certain boundaries Temp, moisture, acidity Monitored by internal systems Feedback mechanisms

energy input, from sun Nutrient Cycling Producers (plants, and other self- feeding organisms)‏ Consumers Animals, most fungi, many protists, many bacteria energy output (mainly metabolic heat)‏

9 C. Living Things: Respond to Stimuli Living things interact with the environment and other LT Response ensures survival of the organism and it often results movement  Vulture can detect and find carcass a mile away and soar toward dinner  Monarch butterfly senses approach of fall and migrates south  Microroganisms can sense light or chemicals  Even leaves of plants follow sun Activities as a result of Responses are termed behavior

11 D. Living Things: Reproduce and Develop Every LT can reproduce or make another organism like itself  Simply split in two  Union of egg and sperm, followed by many cell divisions Must reproduce to ensure continued existence and maintain population

12 E. Living Things: Adapt to Change Adaptation  Modifications that make organisms better able to function in a particular environment  These take a long period time  Leads to evolution Population changes over many generations to better suit their environment

Evolution, the Unifying Concept of Biology Organisms share the same basic characteristics  Cells organized in a similar manner  Genes are composed of DNA  Same metabolic reactions to acquire energy Suggests they are descended from a common ancestor  Evolutionary tree

14 Evolutionary Tree of Life Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. BACTERIA ARCHAEA EUKARYA Protists common ancestor (first cells) cell with nucleus Past Time Present Photosynthetic protist Heterotrophic Protist Plants Fungi Animals common ancestor

15 A. Organizing Diversity Taxonomy:  ID and group organisms according to certain rules  Levels are, from least inclusive to most inclusive: Species, genus, family, order, class, phylum, kingdom, and domain

16 Domains Bacteria - Microscopic unicellular prokaryotes Archaea - Bacteria-like unicellular prokaryotes, living in extreme aquatic environments Eukarya – Eukaryotes (protists, plants, fungi, animals)

Comparison of Life’s Three Domains

18 Scientific Names Binomial nomenclature (two-word names)- used to assign each organism with two part name Latin-based to avoid confusion  First word = genus of organism e.g. Homo  Second word = specific epithet or genus of a species within the genus e.g. Sapience  Always italicized as a Genus species (Homo sapiens)  Genus may be abbreviated e.g. Escherichia Coli as E. Coli

B. Common Descent with Modification Natural Selection – a process by which the environment selects traits to be passed on to the next generation  Biotic and abiotic influence  Mutations fuel by the intro of variations  All individuals can reproduce but not all do with same success rate

Natural selection

21 Organization of the Biosphere Biosphere – air, land, and water where organisms exist Population - Members of a species within an area Community - A local collection of interacting populations making Ecosystems Food webs Chemical cycling and energy flow

22 Terrestrial Ecosystems: A Grassland Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. WASTE MATERIAL, DEATH, AND DECOMPOSITION heat solar energy Chemical cycling Energy flow heat

23 Human Populations Humans modify ecosystems & upset natural nutrient cycles  Ex: tropical rainforest, coral reefs However, humans depend upon healthy ecosystems for  Food  Medicines  Raw materials  Other ecosystem processes

24 Biodiversity Biodiversity – total # & relative abundance of species  The variability of their genes  The ecosystems in which they live Extinction is – the death of a species  Estimates of 400 species/day lost worldwide

25 The Scientific Method: A Flow Diagram Observation New observations are made, and previous data are studied. Hypothesis Input from various sources is used to formulate a testable statement. Conclusion The results are analyzed, and the hypothesis is supported or rejected. Scientific Theory Many experiments and observations support a theory. Experiment/Observations The hypothesis is tested by experiment or further observations. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Courtesy Leica Microsystems Inc.

Warm-Up Question What are the steps of the scientific process? Explain the purpose of each step.

The Scientific Method Scientific method is a standard series of steps in gaining new knowledge through research. Begins with observation Use of senses to understand a natural event After making the observation use inductive reasoning to lead to... Hypothesis - A tentative explanation for what was observed Can be tested Past experiences can influence

28 The Scientific Method: Experimentation Experimentation  Use deductive reasoning to determine how to test If, then logic  Predicts how groups should differ if hypothesis is valid If prediction happens, hypothesis is unchallenged If not, hypothesis is unsupportable

Experimental Design How the scientist will conduct the experiment  Ensures they are testing what they want  Control group  Experimental Group  Could use a model

30 Controlled Experiments Experimental (Independent) variable  Applied one way to experimental group  Applied a different way to control group Response (dependent) variable  Variable that is measured to generate data  Expected to yield different results in control versus experimental group

A couple of biologist had twins, one they called John and the other - control.

32 Results Results or Data  Observable, objective  Mathematical Data – graph/table  Statistical Data - probability that random variation could have caused the results Low probability (less than 5%) is good Higher probabilities make it difficult to dismiss random chance as the sole cause of the results

34 Conclusion Analyze data to reach conclusion as to whether the hypothesis is supported or not Conclusions are what the scientist thinks caused the results  Could lead to the hypothesis for another experiment Report findings in scientific journals to be Peer reviewed Others then attempt to duplicate or dismiss

36 Scientific Theory Scientific Theory:  Joins together two or more related hypotheses  Supported by broad range of observations, experiments, and data  Ex: cell, homeostasis, gene, ecosystem, evolution Scientific Principle / Law:  Widely accepted set of theories

37 A Field Study Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a. Scientist making observations b. Normal mountain bluebird nesting behavior c. Resident male attacking a male model near nest resident male female mate male bluebird model d. Observation of two experimental nests provided data for graph Approaches per Minute nest construction first egg laid hatching of eggs Stage of Nesting Cycle Approaches to male model Approaches to female mate nest 2 nest 1 © Erica S. Leeds