Biology: Exploring Life Chapter 1 Biology: Exploring Life

THE SCOPE OF BIOLOGY 1.1 Life’s levels of organization define the scope of biology 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

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

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

The hierarchy continues downward with Organ systems Organs Tissues Cells Organelles Molecules

1.2 Living organisms and their environments form interconnecting webs 1.2 Living organisms and their environments form interconnecting webs Ecosystems cycle of chemical nutrients from the atmosphere and soil To producers to consumers to decomposers and back to the environment

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

1.3 A cell Is the basic unit of life

New proper ties emerge From the complex organization of a system, such as a cell The whole is greater than the sum of the parts

Contain membrane-enclosed organelles, including a nucleus Eukaryotic cells Contain membrane-enclosed organelles, including a 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 1.4 All forms of life have common features DNA is the genetic information

All organisms share a common set of features Ordered structures 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

1.5 The diversity of life can be arranged into three domains 1.5 The diversity of life can be arranged into three domains Into the prokaryotic domains Bacteria and Archaea and the eukaryotic domain Eukarya

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

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

1.6 Evolution explains the unity and diversity of life 1.6 Evolution explains the unity and diversity of life Charles Dar win synthesized the theory of evolution by natural selection Figure 1.6A

Natural selection is an editing mechanism Natural selection is an editing mechanism organisms have inherited variations, environmental factors favor the reproductive success of some individuals over others then populations change over time 1 2 3 Populations with varied inherited traits Elimination of individuals with certain traits Reproduction of survivors

All organisms have adaptations All organisms have adaptations That enhance survival in their environment Killer whale Pangolin Figure 1.6C

1.7 Two main approaches to learn about nature THE PROCESS OF SCIENCE 1.7 Two main approaches to learn about nature Discovery Science Scientists describe some aspect of the world and use inductive reasoning to draw general conclusions Hypothesis-Based Science Scientists attempt to explain observations by testing hypotheses

1.8 Hypothesis-based science 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 Figure 1.8D Figure 1.8E

Non-Science Many areas of life fall outside the realm of science. Religion, philosophy, ethics, politics, astrology, etc. Science must be consistent, observable, natural, predictable, testable and tentative

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

Technology is the application of science to make life better. Pencil, chair, cell phone, clock, computer…