1. Chapter 1 – The Study of Life
General Biology I
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Caption: This NASA image is a composite of several satellite-based views of Earth. To make the whole-Earth image, NASA scientists combine observations of different parts of the planet. (credit: NASA/GSFC/NOAA/USGS

2. Learning Objectives…by the end of this chapter you should be able to:
Identify the shared characteristics of the natural sciences
Summarize the steps of the scientific method
Compare inductive reasoning with deductive reasoning
Describe the goals of basic science and applied science
Identify and describe the properties of life
Describe the levels of organization among living things
Recognize and interpret a phylogenetic tree
List examples of different subdisciplines in biology

3. Introduction
Biology
The study of living organisms & their interactions with each other and their environment
Biotic environment – living components (predators, symbionts, etc.)
Abiotic environment – physical components (air, soil, water, etc.)
Cells to ecosystems, medicine to environmental science
Escherichia coli (E. coli) bacteria, seen in this scanning electron micrograph, are normal residents of our digestive tracts that aid in the absorption of vitamin K and other nutrients. However, virulent strains are sometimes responsible for disease outbreaks. (credit: Eric Erbe, digital colorization by Christopher Pooley, both of USDA, ARS, EMU)

4. Figure 1. 3. Escherichia coli (E
Figure 1.3. Escherichia coli (E. coli) bacteria, seen in this scanning electron micrograph, are normal residents of our digestive tracts that aid in the absorption of vitamin K and other nutrients. However, virulent strains are sometimes responsible for disease outbreaks. (credit: Eric Erbe, digital colorization by Christopher Pooley, both of USDA, ARS, EMU)

5. Introduction Natural sciences are interdisciplinary
Modern science includes knowledge from many fields
Chemistry, physics, mathematics, computational science, etc.
Life Science (biology) and the Physical Sciences
Biology has many subdisciplines – molecular, cellular, organismal, ecology, etc.
Figure 1.4. The diversity of scientific fields includes astronomy, biology, computer science, geology, logic, physics, chemistry, mathematics, and many other fields. (credit: “Image Editor”/Flickr)

6. Figure 1.2
Formerly called blue-green algae, these (a) cyanobacteria, shown here at 300x magnification under a light microscope, are some of Earth’s oldest life forms. These (b) stromatolites along the shores of Lake Thetis in Western Australia are ancient structures formed by the layering of cyanobacteria in shallow waters. (credit a: modification of work by NASA; credit b: modification of work by Ruth Ellison; scale-bar data from Matt Russell)

7. The Process of Science Science
Seeks general truths or operation of general laws
Especially those acquired and tested by the scientific method
Hypothesis – thoughtful explanation that accounts for some natural phenomenon, that can be tested
not just a “educated guess”

8. The Process of Science Scientific Reasoning – “a way of knowing”
Inductive reasoning
Uses related observations to arrive at a more general conclusion, based on evidence – part of “observational” science
Process used to formulate hypothesis about natural phenomena
Deductive reasoning
Uses general principle (hypothesis) to make predictions about future results.
Testing these predictions is large part of hypothesis-based science
Both types of reasoning involved in “good” science

9. Figure 1.7. Two types of reasoning
Scientists use two types of reasoning, inductive and deductive reasoning, to advance scientific knowledge.
As is the case in this example, the conclusion from inductive reasoning can often become the premise for deductive reasoning.
Can view inductive reasoning as developing a testable hypothesis from observations; deductive reasoning is making predictions based on the hypothesis, then testing it

10. The Process of Science The Scientific Method
A general logical, rational problem-solving method
Starts with observation(s) that leads to a question
From this question, a hypothesis (a possible explanation) is proposed to answer question
Hypotheses must be falsifiable and testable – the potential to be disproven by experimentation
Science does not “prove” anything – always open to modification
Example of inductive reasoning

11. Figure 1.5. Sir Francis Bacon (1561–1626) is credited with being the first to define the scientific method. (credit: Paul van Somer)

12. Figure 1.6. The scientific method consists of a series of well-defined steps. If a hypothesis is not supported by experimental data, a new hypothesis can be proposed.

13. The Process of Science The Scientific Method Prediction
proposed based on the hypothesis
Can take the form of an if…then statement. If (the hypothesis is true),… then (we expect this to happen)
Design an experiment to test the prediction
Prediction should be stated within the context of the experimental design

14. The Process of Science The Scientific Method Experimental design
Has one or more variables and controls
Variables – part of the experiment that can change (vary) – ‘experimental groups’ or ‘treatments’
Controls – under same conditions as the treatments, except it lacks the manipulation
Compare the treatment groups with the control group(s) – use appropriate statistical methods

15. The Process of Science The Scientific Method
Analyze experimental results
If results do not match the predictions, then the hypothesis is rejected.
One may modify the falsified hypothesis and try again, or start over completely
There may be alternative hypotheses that are more appropriate
If results match the prediction, the data support the hypothesis
Positive results do not ‘prove’ hypothesis since there may be other reasons the data may be explained
Both positive and negative results should be reported to the scientific community (both are valuable)

16. The Process of Science Example – Drug discovery
Observation – scientists have found that many organisms, including many plants and simple marine organisms (e.g. sponges), produce chemicals that can treat a variety of diseases and medical conditions
Question – can a common sponge be used to treat cancer?
Hypothesis – the extract from this sponge kills cancer cells cultured in a petri dish

17. The Process of Science Example – Drug discovery
Prediction – if sponge extract is added to cultured cancer cells, the cells will die
Experiment – grow cancer cells in 20 petri dishes
Treatment: Sponge extract dissolved in water is added to 10 dishes
Control: pure water (placebo) is added to the other 10 dishes
Survival of cancer cells is followed for an appropiate amount of time
Survival rates are compared between the treatment and control groups
Replication – multiple samples in each group helps to reduce experimental bias and chance results

18. The Process of Science Example – Drug discovery Analyze results
If survival of cancer cells is higher in the control, compared to the treatment group (with sponge extract), then the data matches the prediction and supports the hypothesis
If survival is the same in both groups, or higher in the treatment group, the data do not match the predictions, and the hypothesis is rejected
Additional experiments are required to determine the active ingredient, and if the extract is effective in whole organisms

19. The Process of Science The Scientific Method Not as rigid as indicated
Some questions are difficult to approach experimentally
Climate science, paleontology
Good science can be performed using many different approaches
Observational studies
Comparative studies
Experimental (manipulative) studies
Computational/modeling studies
An example of an observational approach… using transects and quadrat sampling to quantify an ecosystem. (Image courtesy of B. Tyler)

20. The Process of Science Scientific theory
A large body of knowledge based on many confirmed hypotheses – working concepts of science
Explains many observations, widely supported by evidence, typically from many different fields
Very broad, encompassing many hypotheses
Although often challenged, never demonstrated to be untrue
Don’t confuse with “common” definition – more like a hypothesis (“I’ve got a theory about that”)
Examples: Atomic theory, plate tectonic theory, evolutionary theory

21. The Process of Science Two types of science: Basic and Applied
Basic science (“pure” science)
Basic understanding of natural phenomenon
Expands knowledge for knowledge’s sake
Seeks answers to questions regardless of it applicability
Applied science (“technology”)
Addresses “real-world” problems – environmental problems, agriculture, medicine
Often starts with basic understanding (basic science) – human genome project started with understanding of basic genetics and molecular biology – applied to treating genetic diseases

22. Figure 1. 8. After Hurricane Ike struck the Gulf Coast in 2008, the U
Figure 1.8. After Hurricane Ike struck the Gulf Coast in 2008, the U.S. Fish and Wildlife Service rescued this brown pelican. Thanks to applied science, scientists knew how to rehabilitate the bird. (credit: FEMA)

23. Figure 1.9
The Human Genome Project was a 13-year collaborative effort among researchers working in several different fields of science. The project, which sequenced the entire human genome, was completed in (credit: the U.S. Department of Energy Genome Programs (

24. Themes and Concepts of Biology
Properties of Life
Order
All organisms are highly organized
Atoms combine to form molecules which in turn are organized into organelles, which are organized into cells
All multicellular organisms are made of cells
A toad represents a highly organized structure consisting of cells, tissues, organs, and organ systems. (credit: “Ivengo”/Wikimedia Commons)

25. Figure All molecules, including this DNA molecule, are composed of atoms. (credit: “brian0918”/Wikimedia Commons)

26. Themes and Concepts of Biology
Properties of Life
Sensitivity/Response to Stimuli
Organisms are take in information from the environment (stimuli) and must be able to respond to it (attracted/repelled/etc.)
lants
The leaves of this sensitive plant (Mimosa pudica) will instantly droop and fold when touched. After a few minutes, the plant returns to normal. (credit: Alex Lomas)

27. Themes and Concepts of Biology
Properties of Life
Reproduction
Duplicate their DNA, cells divide
Multicellular organisms produce germline cells to form new individuals
DNA is passed from parent to offspring – passing along similar genetic characters (heredity)

28. Themes and Concepts of Biology
Properties of Life
Growth and development
Genes (DNA) provide “blueprint” for growth and development
Offspring grow up with similar characters as their parents
Although no two look alike, these kittens have inherited genes from both parents and share many of the same characteristics. (credit: Rocky Mountain Feline Rescue)

29. Themes and Concepts of Biology
Properties of Life
Regulation
Multiple regulatory mechanisms of internal functions
Coordinate internal body functions (nervous and endocrine systems)
Coping with environmental stress
Homeostasis
Steady state
Maintenance of consistent, appropriate conditions inside the cell or body
Thermoregulation, acid-base balance, electrolytes balance
Polar bears (Ursus maritimus) and other mammals living in ice-covered regions maintain their body temperature by generating heat and reducing heat loss through thick fur and a dense layer of fat under their skin. (credit: “longhorndave”/Flickr)

30. Themes and Concepts of Biology
Properties of Life
Energy processing
All organisms utilize energy
Autotrophs – obtain energy from the sun, produce own organic molecules (plants, cyanobacteria)
Heterotrophs – obtain energy and organic molecules from other organisms (animals, fungi)
The California condor (Gymnogyps californianus) uses chemical energy derived from food to power flight. California condors are an endangered species; this bird has a wing tag that helps biologists identify the individual. (credit: Pacific Southwest Region U.S. Fish and Wildlife Service)

31. Themes and Concepts of Biology
Organizational heirarchy
Atoms – smallest whole unit of matter
Molecules – made up of bound atoms
Macromolecules – large molecules
Organelles – specialized functions within a cell
Cells – the basic unit of life
Tissues – groups of similar cell types
Organs – groups of tissues working together
Organ system – groups of related organs (digestive, respiratory, etc.)
Organism

32. Themes and Concepts of Biology
Organizational heirarchy
Organism
Population – group of same species – able to interbreed
Community – populations living in the same habitat
Ecosystem – biotic and abiotic components of the habitat
Biosphere – all ecosystems on Earth

33. Figure 1.16
The biological levels of organization of living things are shown. From a single organelle to the entire biosphere, living organisms are parts of a highly structured hierarchy. (credit “organelles”: modification of work by Umberto Salvagnin; credit “cells”: modification of work by Bruce Wetzel, Harry Schaefer/ National Cancer Institute; credit “tissues”: modification of work by Kilbad; Fama Clamosa; Mikael Häggström; credit “organs”: modification of work by Mariana Ruiz Villareal; credit “organisms”: modification of work by “Crystal”/Flickr; credit “ecosystems”: modification of work by US Fish and Wildlife Service Headquarters; credit “biosphere”: modification of work by NASA)

34. Themes and Concepts of Biology
Diversity of Life
Enormous diversity of life: 8.7 (±1.3) million to upwards of 1 trillion species (mostly microbes) estimated
About 1.6 million have been “databased”
Diversity is due to evolution – process of gradual change over time from which new species arise
Phylogenetic tree – diagram showing evolutionary relationships

35. Three Domains of life Bacteria Archaea (ancient ones) Eukarya
Prokaryotes
Figure This phylogenetic tree was constructed by microbiologist Carl Woese using data obtained from sequencing ribosomal RNA genes. The tree shows the separation of living organisms into three domains: Bacteria, Archaea, and Eukarya. Bacteria and Archaea are prokaryotes, single-celled organisms lacking intracellular organelles. (credit: Eric Gaba; NASA Astrobiology Institute)

36. Themes and Concepts of Biology
Diversity of Life
Phylogenetic trees have nodes and branches (clades)
Internal nodes denote when ancestors split to form two new species
Length of branch – time elapsed since split

37. Figure 1.18
These images represent different domains. The (a) bacteria in this micrograph belong to Domain Bacteria, while the (b) extremophiles (not visible) living in this hot vent belong to Domain Archaea. Both the (c) sunflower and (d) lion are part of Domain Eukarya. (credit a: modification of work by Drew March; credit b: modification of work by Steve Jurvetson; credit c: modification of work by Michael Arrighi; credit d: modification of work by Leszek Leszcynski)

38. Themes and Concepts of Biology
Branches of Biological Study
Scope of biology is broad and interdisciplinary
Many subdisciplines to specialize, e.g. …
Molecular biology and biochemistry
Microbiology
Organismal biology
Physiology
Ecology
Paleontology
Zoology
Botany
Most subdisciplines today incorporate information, concepts and tools from other subdisciplines;
Neurobiology – uses molecular, cellular, developmental, medical and computational approaches

39. Figure 1.19
This forensic scientist works in a DNA extraction room at the U.S. Army Criminal Investigation Laboratory at Fort Gillem, GA. (credit: United States Army CID Command Public Affairs)

40. Figure 1.20
Researchers work on excavating dinosaur fossils at a site in Castellón, Spain. (credit: Mario Modesto)