Chapter 1: Biology: Exploring Life

What is Biology? The study of life or living organisms.

Ecosystem Community Population Organism Organ Systems Tissue Cell Molecule Atom Organs Organelle 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 Nucleus Brain Spinal cord Nerve

Levels of Organization (large scale) Ecosystem –Both living organisms and non- living or physical components of environment in a particular area

Levels of Organization (large scale) Community –All interacting organisms in an area (living component only)

Levels of Organization Population Individuals of one species living in same area

Levels of Organization Individual –One organism

Levels of Organization (within an Individual) Organ Systems –group of organs that work together in performing vital body functions excretory, nervous

Levels of Organization (within an Individual) Organs –structure consisting of several tissues adapted as a group to perform specific functions liver, intestine liver

Levels of Organization (within an Individual) Tissues –integrated group of cells with a common function, structure, or both Bone tissue

Levels of Organization (within an Individual) Cell – Unit of living matter separated from environment by its membrane red blood cell

Organelles Membrane bound Packages of goodness

Levels of Organization (within an Individual) Molecule –Cluster of atoms DNA, lipid, carbohydrate

Levels of Organization (within an Individual) Atom –Smallest particle of ordinary matter

Emergent properties New properties that emerge with each step in the hierarchy of life –e.g., birth rate, death rate is studied at population level, not organismal level or molecular level

Interconnected Webs producers –photosynthetic organisms –provide food for others consumers –eat plants or other animals decomposers –act as recyclers, breaking down dead matter to simple mineral nutrients

Ecosystem Producers (such as plants) Sunlight Cycling of chemical nutrients Chemical energy Consumers (such as animals) Heat

Cells: structural functional units of life Cells- –most basic unit of life –can perform all functions necessary for life.

Common Features of All Life Properties All Life Has in Common 1.Order 2.Regulation 3.Growth and development 4.Energy processing 5.Response to Environment 6.Reproduction 7.Evolutionary adaptation

Three Domains of Life taxonomy –branch of biology that names & classifies species

Three Domains of Life Domain –Highest level of taxonomic classification used by biologists 1.Bacteria 2.Archaea 3.Eukarya prokaryotes

Bacteria

Archaea

In Prokaryotes, the cells do not have a nucleus

Eukarya –Cells DO have nucleus –Includes all organisms except prokaryotes Plantae AnimaliaFungi

Unifying Theory Of Biology Theory –Comprehensive idea that has great explanatory power Evolution –Heritable changes that have produced Earth ’ s diversity of organisms –proceeds through process of natural selection

Charles Darwin Wrote: “ On the Origin of Species by Means of Natural Selection ”

Charles Darwin Two main concepts: –species living today descended from ancestral species –natural selection occurs as heritable variations are exposed to environmental factors that favor reproductive success of some individuals over others

Natural Selection –Inherited traits favor reproductive success of some individuals over others in a changing environment

1 2 3 Populations with varied inherited traits Elimination of individuals with certain traits Reproduction of survivors

Natural Selection Important Components –Variation or variability in inherited traits in a population –Environmental Factors –Reproductive Success of Some Individuals

Natural Selection The process of natural selection leads to ADAPTATIONS. evolutionary adaptation- inherited characteristic that enhances an organism ’ s ability to survive and reproduce in a particular environment.

Name Those Adaptations Polar Bear

Name Those Adaptations Bats

Name Those Adaptations Dolphin

Name Those Adaptations platypus

Name Those Adaptations Three-toed sloth

Name Those Adaptations Flamingo

Name Those Adaptations Rattlesnake

Name Those Adaptations Tiger

Science is Latin for “ to know ” So why do we do it?

The Process of Science First Approach –Discovery science Scientists describe some aspect of the world use inductive reasoning, to draw general conclusions

What is Inductive Reasoning? Take a lot of observations and from these draw general conclusions Specific to general

The Process of Science Second Approach –Hypothesis Driven Use deductive reasoning Propose hypothesis Make deductions leading to predictions Then test hypothesis

What is Deductive Reasoning? “ if, then ” statements From general ideas to specific observations Opposite of inductive

The Scientific Method 1.Observation 2.Questions 3.Hypotheses 4.Predictions 5.Tests

The Flying Squirrel Step 1: An Observation When flying squirrels land on a tree they scramble to the other side.

Step 2: The Question Why do they do that? Or more specifically why do flying squirrels always move to the opposite side of the tree when they land?

Step 3 Hypothesis Squirrels move around tree to prevent predation Alternative Hypothesis: Move around tree to avoid bright moonlight.

Hypothesis Tentative answer to a question An “ educated guess ” Alternative Hypothesis Another possible explanation or answer to a question

Step 4: Predictions If squirrels move around the tree to avoid predation, then squirrels that do NOT move will be preyed on and those that do move will not be preyed on. If the squirrel move around tree to avoid light then if we observe them landing on the dark side they should NOT move.

Step 5: The Tests Ideas?

Results Predation Experiment –No difference in predation rate between squirrels that land on one side of the tree and move and squirrels that do not move Do our results support or falsify our hypothesis? Squirrels move around tree to prevent predation Original hypothesis

Results Light Experiment –We find that when we watch squirrels landing on both light and dark sides of the tree, those that land on the light side scramble to other side, those on the dark side don ’ t Squirrels move around tree to avoid light Original hypothesis Do results support or falsify our hypothesis?

Steps of the Scientific Method Observation Question Hypothesis Prediction Test: Experiment or additional observation Test does not support hypothesis; revise hypothesis or pose new one Test supports hypothesis; make additional predictions and test them