Biology: Exploring Life Chapter 1 Biology: Exploring Life

What is Biology Biology can be defined as the study of Life “Bio” means Life and “ology” means Study Of It is a branch of science and a way of studying nature.

What is a biologist A Biologist is a person who strives to understand, explain and describe the natural world of living things. Biologists try to answer questions about The number of organisms The kinds of organisms The rate of reproduction The relationships among all organisms Biologists focus on questions that deal with how life works not why should there be life.

Why Study Biology Biology is relevant Great advances have been made in controlling and treating diseases caused by viruses, bacteria, parasites and organ failure Agricultural Biologists use bioengineering to develop new genetically enhanced pest resistant crops In making decisions about where to locate new living spaces for an ever increasing human population In bridging the gap between biology and technology related careers in the biotech fields of laboratory science and applied ecology.

THE SCOPE OF BIOLOGY Life’s levels of organization define the scope of biology Life’s structural hierarchy Defines the scope of biology, the scientific study of life Biosphere Ecosystem Florida coast Community All organisms on the Florida coast Population Group of brown pelicans Organism Brown pelican Organ system Nervous system Organ Brain Tissue Nervous tissue Cell Nerve cell Organelle Nucleus Molecule DNA Atom Spinal cord Nerve

All the living organisms in an ecosystem An ecosystem consists of all the organisms living in a par ticular area As well as the nonliving environmental components All the living organisms in an ecosystem Make up a community

An individual living entity A population Consists of a localized group of individuals of a species An individual living entity Is an organism

The hierarchy continues downward with The hierarchy continues downward with Organ systems Organs Tissues Cells Organelles Molecules Biosphere Ecosystem Florida coast Community All organisms on the Florida coast Population Group of brown pelicans Organism Brown pelican Organ system Nervous system Organ Brain Tissue Nervous tissue Cell Nerve cell Organelle Nucleus Molecule DNA Atom Spinal cord Nerve

Living organisms and their environments form interconnecting webs Ecosystems are characterized by the cycling of chemical nutrients from the atmosphere and soil To producers to consumers to decomposers and back to the environment Sun Air CO2 O2 H2O Chemical energy Inflow of light Loss heat Producers Cycling nutrients Consumers Decomposers Soil Ecosystem

Energy flows one-way through an ecosystem Energy flows one-way through an ecosystem From the sun to producers to consumers and exits as heat Sun Air CO2 O2 H2O Chemical energy Inflow of light Loss heat Producers Cycling nutrients Consumers Decomposers Soil Ecosystem Figure 1.2

Cells are the structural and functional units of life Cells are the structural and functional units of life A cell Is the basic unit of life

New proper ties emerge From the complex organization of a system, such as a cell

Eukaryotic cells Prokaryotic cells Eukaryotic cells Contain membrane-enclosed organelles, including a DNA-containing nucleus Prokaryotic cells Lack such organelles Nucleus (contains DNA) Eukar yotic cell Prokar yotic cell DNA (no nucleus) Organelles 25,000  Figure 1.3

EVOLUTION, UNITY, AND DIVERSITY The unity of life: All forms of life have common features DNA is the genetic information For constructing the molecules that make up cells and organisms

Each species’ genetic instructions Each species’ genetic instructions Are coded in the sequences of the four building blocks making up DNA’s two helically coiled chains A C T G

All organisms share a common set of features All organisms share a common set of features Ordered structures Regulation of internal conditions Figure 1.4B Figure 1.4C

Growth and development Energy use Response to environmental stimuli Growth and development Energy use Response to environmental stimuli The ability to reproduce and evolve Figure 1.4D Figure 1.4E

The diversity of life can be arranged into three domains The diversity of life can be arranged into three domains Organisms are grouped (classified) Into the prokaryotic domains Bacteria and Archaea and the eukaryotic domain Eukarya

Domains Bacteria and Archaea Domains Bacteria and Archaea SEM 25,000 Figure 1.5B SEM 3,250 Figure 1.5A

Domain Eukarya includes Domain Eukarya includes Protists (protozoans and algae, falling into multiple kingdoms) The kingdoms Fungi, Plantae, and Animalia Kingdom Fungi 275 Kingdom Animalia Protists (multiple kingdoms) Kingdom Plantae Figure 1.5C

Evolution explains the unity and diversity of life Evolution explains the unity and diversity of life Charles Dar win Synthesized the theory of evolution by natural selection

Natural selection is an editing mechanism Natural selection is an editing mechanism That occurs when populations or organisms, having inherited variations, are exposed to environmental factors that favor the reproductive success of some individuals over others 1 2 3 Populations with varied inherited traits Elimination of individuals with certain traits Reproduction of survivors Figure 1.6B

All organisms have adaptations All organisms have adaptations That have evolved by means of natural selection Killer whale Pangolin Figure 1.6C

THE PROCESS OF SCIENCE Scientists use two main approaches to learn about nature Science Is a way of knowing Seeks natural causes for natural phenomena

Discovery Science In discovery science Discovery Science In discovery science Scientists describe some aspect of the world and use inductive reasoning to draw general conclusion.

With hypothesis-based science, we pose and test hypotheses With hypothesis-based science, we pose and test hypotheses Hypothesis-based science involves Obser vations, questions, hypotheses as tentative answers to questions Deductions leading to predictions, and then tests of predictions to see if a hypothesis is falsifiable (Deductions are based on previous research and reliable fact based information).

A Case Study from Ever yday Life A Case Study from Ever yday Life Deductive reasoning is used in testing hypotheses as follows If a hypothesis is correct, and we test it, then we can expect a par ticular outcome Observations Question Hypothesis # 1: Dead batteries Hypothesis # 2: Burnt-out bulb Prediction: Replacing batteries will fix problem Replacing bulb Test prediction Test falsifies hypothesis Test does not falsify hypothesis Figure 1.8A

Percent of total attacks A Case Study of Hypothesis-Based Science In experiments designed to test hypotheses The use of control groups and experimental groups helps to control variables Percent of total attacks on artificial snakes 100 80 60 40 20 83% 17% 16% 84% Artificial king snakes Artificial brown snakes Coral snakes absent present Figure 1.8B Figure 1.8C Bar Graph-comparison of individual groups at one point in time

Biology is connected to many impor tant issues in our lives Biology is connected to many impor tant issues in our lives Environmental problems and solutions Genetic engineering Medicine Figure 1.9

Many technological advances Many technological advances Stem from scientific research The development of medicines to treat illness The development of devices to see inside of the human body The science-technology-society relationship Is an impor tant aspect of a biology course Enables students and their families to make intelligent decisions about health care Development of goods and services to improve the living standard throughout the world