Exploring Life Chapter Key Concepts: 1- From microscopic to global scale 2- Complexity of biological systems 3- Across great diversity 4- Evolution: life unity and diversity 5- Methods of inquiry

Biology is the scientific study of life. The Scope of Life Biology is the scientific study of life. Life is structured on a size scale ranging from: The molecular scale to The global scale. The scope of Biology stretches across: The enormous diversity of life on Earth.

Properties and Processes Associted with Life Order Regulation Growth and development Energy processing Response to the environment Reproduction Evolutionary adaptation

Figure 1.2

Range of Life Organizational Levels Biologists explore life at levels ranging from: The biosphere, to The molecules that make up cells.

Levels of Biological Organization Biosphere: All environments on earth that support life Environments include: Most regions of land Most bodies of water (oceans, lakes, and rivers) Inner atmosphere (several kilometers)

Levels of Biological Organization Ecosystem (forests, deserts, coral reef): All organisms living in a particular area Affected by: Nonliving component of the environment: Water, air, soil & sunlight Community: All organisms in an ecosystem (many species) Population: Group of interacting individuals of one species

Levels of Biological Organization Organism: An individual living thing Organ system: Several organs make up a system (circulatory) Organ: Made of several different tissues (heart) Tissue: Group of similar cells performing specific function

Levels of Biological Organization Cell: Basic unit of life capable of reproduction Molecules: Chemical units of the cell, made of atoms (DNA) Atoms: Smaller chemical units

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Break Slide Aug , ‘14

Ecosystems Each organism interacts continuously with its environment. Both organism and environment are affected by this interaction. The dynamics of any ecosystem depend on two processes: Cycling of nutrients (within the ecosystem) Flow of energy (through the ecosystem)

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Two major types of cells: Cells and Their DNA The cell: Lowest level of structure (structural organization) Can perform all activities required for life. All organisms are composed of cells. Two major types of cells: Prokaryotic Eukaryotic

The prokaryotic cell: The eukaryotic cell: Small and simple Contains no organelles. Contains no nucleus (DNA?) The eukaryotic cell: Larger and more complex Contains organelles. The nucleus is the largest organelle in most eukaryotic cells.

Figure 1.5

Genetic engineering & biotechnology allowed us to: All cells: Use DNA as the chemical material of genes. Genes are: Units of inheritance on the DNA (Parts of DNA) Transmit information from parents to offspring. Genetic engineering & biotechnology allowed us to: Manipulate the DNA and genes of organisms. The DNA language consists of just four letters The four letters are A, G, C, and T

Consists of four letters A: for Adenine The DNA language: Consists of four letters The four letters are: A: for Adenine G: for Guanine C: for Cytosine T: for Thymine Figure 1.6

Life in Its Diverse Forms Diversity is the hallmark of life. The diversity of known life includes: 1.8 million species. Estimates of the total diversity: Range from 10 million to over 200 million species.

Grouping Species: The Basic Concept Biodiversity can be both: Beautiful, & Overwhelming. Taxonomy is the branch of biology that: Names species Classifies species. Formalizes the hierarchical order of organisms.

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The Three Domains of Life The three domains of life are: Bacteria (prokaryotic) Archaea (prokaryotic) Eukarya (eukaryotic)

Figure 1.9.1

Eukarya includes at least four kingdoms: Plantae: Make their own food, photosynthesis Fungi : Obtain food by digesting dead organisms Animalia: Ingest & digest other organisms Protista: Multiple kingdoms, mostly single cell

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Unity in the Diversity of Life Underlying the diversity of life is a striking unity This is especially seen at lower levels of structure. Example: the universal genetic language of DNA Biological evolution accounts for this combination of: Unity, & Diversity.

The Darwinian View of Life Evolutionary view of life: Came into focus in 1859 When Charles Darwin published : The Origin of Species.

Darwin’s book developed two main points: Descent with modification Natural selection Darwin’s theory of natural selection is based on: Fact 1: Overproduction and competition Fact 2: Individual variation The inescapable conclusion: Unequal reproductive success

Darwin called unequal reproductive success natural selection. The product of natural selection is adaptation. Natural selection is the mechanism of evolution. The light colored beetle example

Figure 1.14

Artificial selection: Types of Selection Artificial selection: Is the selective breeding by humans of: Domesticated plants Domistcated animals Example of natural selection in action: Development of antibiotic-resistant bacteria .

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The word science is derived from a Latin verb meaning “to know.” The Process of Science The word science is derived from a Latin verb meaning “to know.” Science developed from people’s curiosity about: Themselves The world around them. Two main scientific approaches: Discovery science Hypothesis-driven science

Seeks natural causes for natural phenomena. Discovery Science Seeks natural causes for natural phenomena. Limits studies to structures & processes that are: Observable Measurable In biology: It enables description of life at its many levels. Can lead to important conclusions based on a type of a generalized logic called inductive reasoning

Hypothesis-Driven Science Observations associated with: Asking questions Seeking explanations Investigation involves: A series of steps called scientific method. A hypothesis is: A tentative answer to a question.

An investigatior can use deductive logic to test the hypothesis. In deduction, the reasoning flows from the general to the specific.

Figure 1.18

In the process of science, the deduction usually takes the form of: Predictions about experimental results. Then the hypothesis is tested by: Performing an experiment to see whether the results are as predicted.

Figure 1.19

The Process of Science: Can colors protect a Snake? One way about how hypothesis-based science works is: Examining a case study: An in-depth examination of an actual investigation. Copyright © 2007 Pearson Education Inc., publishing as Pearson Benjamin Cummings

Figure 1.20

Biologists developed a hypothesis regarding mimicry in snakes. They tested the hypothesis by: making artificial snakes observing how often they were attacked Attackers are the snake predators. Results: Figure 1.21 below

Figure 1.21

This is an example of a controlled experiment. An experiment designed to compare two groups An experimental group and a control group. Ideally, the two groups differ in only one variable.

Scientists build on what has been learned from earlier research. The Culture of Science Scientists build on what has been learned from earlier research. They pay close attention to contemporary scientists working on the same problem. Both cooperation and competition characterize the scientific culture. Scientists check the conclusions of others by: Attempting to repeat experiments.

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Science, Technology, and Society Science and technology are interdependent. New technologies advance science. Scientific discoveries lead to new technologies. Example: The discovery of the structure of DNA 50 yr ago led to a variety of DNA technologies.

Figure 1.23

Technology has improved our standard of living in many ways, yet it is a double-edged sword: In the past 300 years: It has kept people healthier It enabled a tenfold human population growth Population growth may have devastating environmental consequences

Evolution Connection: Theories in Science What is a scientific theory, and how is it different from a hypothesis? A theory is broader in scope than a hypothesis. Theories only become widely accepted in science, if they are supported by: An accumulation of extensive and varied evidence.

Scientific theories are not the only way of “knowing nature.” Science and religion are two different ways of trying to make sense of nature.