LifeLife is an organized genetic unit capable of

metabolism, reproduction and evolution

BiologyBiology: Is a branch of Life Science, and is

the study of living organisms and how they react to their environment.

Biology (cont.)Biology deals with every aspect of life in a

living organism. Biology examines the structure, function, growth, origin, evolution, and distribution of living things.

Biology (cont.). It classifies and describes organisms,

their functions, how species come into existence, and the interactions they have with each other and with the natural environment.

Biology: Exploring LifeThe scope of

biologyEvolution, unity,

and diversityThe process of

scienceBiology and

everyday life

Living organisms have an organized structure

Atoms form molecules that are organized into macromolecules that form cell components, called organelles.

Organisms may be unicellular or multicellular.

Multicellular organisms have structural levels above the cell: tissues, organs and organ systems.

Biological Organization

Molecule Organelle Cells Tissues Organ Organism

Structure and FunctionThe structure and

function of organisms is correlated at all levels of biological organization.

The continuity of life on earth is based on the inheritable information of thegenetic molecule, DNA. DNA molecules contain the instructions needed for theorganization and structure of organisms.

The internal functions of cells and organisms are coordinated through regulatory mechanisms. Such regulation includes on the cellular level, moving materials through membranes, transporting nutrients and wastes to and from cells and cell to-cell communication.

Thousands of chemical reactions that convert matter and energy occur within anorganism so the organism can function. Metabolism is under the control of DNA,the genes.

Organisms respond to environmental stimuli. We readily see this with ourselvesand other animals, but we may have less experience noting how other organismsrespond to stimuli, whether it is a flower tracking the sun, a cellular slime moldaggregating in response to a chemical signal, or a Venus Fly-trap capturing prey.

Regulatory systems help living organisms adjust to changing conditions by actively maintaining their structure and internal environment, a process called homeostasis, to ensure a dynamic balance. Organisms have a variety of regulatory and feedback systems, both positive and negative, in place to provide for orderand functioning.

Negative Feedback Pathway Positive Feedback Pathway

The complexity of life challenges biologists who try to unravel the whole to viewthe component parts for research and learning. To do so, we most often mustTaking apart the whole, and in doing so, disrupt its function. The human genomeproject – the attempt to discern the DNA sequences of the human chromosomes,has been a daunting project – and just the beginning of trying to determine whatthose sequences mean in terms of gene function and products.

DNA Sequencing Laboratory

Levels of Organization BiosphereEcosystemCommunityPopulationOrganismOrgan

SystemOrgansTissuesCellOrganelleMolecule

biosphere - of the Universe, only where life exists biome - large unit of land or water with similar characteristics, e. g. desert ecosystem - functional unit of nature including organisms and environment community - several populations of interacting organisms, e. g. Big Creek population - a local group of one kind of organisms, e. g. cardinals organism - an individual of a kind (species) of which there are 2 types: multicellular & unicellular (in case of the latter, organ and tissue level does not exist) organ system - group of organs with a coordinated role, e. g. excretory organ - group of tissues with a coordinated role, e. g. kidney tissue - group of similar cells, e. g. cardiac muscle cell - basic unit of life organelle - sub-cellular units with a specific function, e. g. mitochondrion molecule - one or more different kinds of atoms bonded together atom - smallest particle of an element sub-atomic particle - proton, neutron, electron

Organizational Hierarchy of Life biosphere - of the Universe, only where life exists biome - large unit of land or water with similar characteristics, e. g. desert ecosystem - functional unit of nature including organisms and environment community - several populations of interacting organisms, e. g. Big Creek population - a local group of one kind of organisms, e. g. cardinals

organism - an individual of a kind (species) of which there are 2 types: multicellular & unicellular (in case of the latter, organ and tissue level does not exist) organ system - group of organs with a coordinated role, e. g. excretory organ - group of tissues with a coordinated role, e. g. kidney tissue - group of similar cells, e. g. cardiac muscle cell - basic unit of life organelle - sub-cellular units with a specific function, e. g. mitochondrion molecule - one or more different kinds of atoms bonded together atom - smallest particle of an element sub-atomic particle - proton, neutron, electron

ExamplesEcosystem

All living and non-living components in an area (water, air, etc.)

CommmunityEntire array of

organisms in an area

PopulationInteracting group of

individuals of one species

Living Organisms and Their Environment Form Webs

ProducersPlants,

photosynthetic organisms

Produce sugar from sunlight

ConsumersEat plants, other

organismsUse energy from

consumed foods

Cells are the structural and functional units of life

Lowest level of organization that can perform all the activities required of life

Emergent properties: novel properties that emerge with each step up in the levels of organization

Cell TypesProkaryotic

SimpleSmallNo organellesEnclosed by a

membrane that regulates traffic

Use DNA as code for genetic info

Example: Bacteria

EukaryoticComplexLargeContain membrane

bound organellesEnclosed by a

membrane that regulates traffic

Use DNA as code for genetic info

Examples: plants, fungi, animals

The Unity of LifeFoundation for unity of life: DNAEach molecule = 2 long chains coiled

into a double helixThere are only 4 chemical building

blocks: A, T, G, CSequence of the 4 bases is critical to the

message: rat, tar, art all have the same letters,

different meaning

More UnityOrder

Complex organizationRegulation

As environment changes, mechanisms regulate organism’s internal environment

Growth and DevelopmentGenes carry code for

growth and development

Energy UtilizationTake in energy and

convert it to run basic processes

Response to EnvironmentAll organisms respond to

their environmentReproduction

Reproduce their own kind

EvolutionSpecies change over

time

Organizing the OrganismsTaxonomy: names and classifies speciesSpecies: a particular type of organism (stay

tuned for a more precise definition)Several levels of taxonomic organization:

domainkingdomphylumclassorderfamilygenusspecies

The Levels of OrganizationDomain: highest

level of taxonomic organization (think continent)

Kingdom (think country)

Phylum (think state)Class (think county)

Order (think city)Family (think street)Genus (think house)Species (think room)

We can now get even more specific (area within the room, chair within that area, etc.)

Levels of Organization

The Three Domains

BacteriaProkaryotic, most are unicellular and

microscopic, contains kingdom BacteriaArchaea

Prokaryotic, most are unicellular and microscopic, contains kingdom Archaea

Some unique environmental tolerances

The Three Domains, cont.Eukarya

Eukaryotic, many multicellular, contains 4 kingdoms

Evolution Explains the Unity and Diversity of LifeNovember 1859, Charles Robert Darwin

published On the Origin of Species by Means of Natural Selection

Presented evidence that support the view that modern species are descended from ancestral species (descent with modification)

Proposed natural selection as the mechanism of change

How Does it Work?Unequal reproductive success results in a

greater abundance of some traits (those that make reproduction more likely), and lesser abundance of some traits (those that do not favor reproduction)

Natural selection isn’t a creative mechanism- it can only edit what is there!

How Do Scientists Do Science?Discovery Science

Involves verifiable observations and measurements

Relies on inductive reasoning (derives principles from many specific observations)

Hypothesis-Based ScienceInvolves hypotheses (tentative answer to a

question) and rigorous testingRelies on deductive reasoning (from a general

premise, we can extrapolate to the specific results we expect)

Scientific Method

Scientific Method example

Google MapsThe Mall

Concept CheckNot all science discoveries strictly follow the “scientific method”. Which of the following would best be described as discovery science?

Sequencing the human genome. Describing a new bird species from the Philippines. A project to find preserved specimens of the probably

extinct Rocky Mountain locust frozen in glaciers . All of the above.

AnswerNot all science discoveries strictly follow the “scientific method”. Which of the following would best be described as discovery science?

All of the above.

What’s the Process?Make an observationAs a question based on the observationDevelop an hypothesis (tentative answer to

your question)Test your hypothesisDid you accept or reject your hypothesis?

Interpreting DataThese two snakes look remarkably similar to each other. The coral snake (right) is very poisonous to vertebrates. Hypotheses:H1: The coral snake’s bright color pattern serves to warn off potential predators.H2: The the king snake suffers less predation because it mimics or looks like the coral snake. H3: The protection that king snakes receive by mimicking coral snake will depend on the presence of coral snakes.

Interpreting DataA team of scientists designed an investigation that used artificial snakes to test the previous hypotheses. Which of the previous hypotheses are supported by the results displayed at the right?

H1: The coral snake’s bright color pattern serves to warn off potential predators.

H2: The king snake suffers less predation because it mimics or looks like the coral snake.

H3: The protection that king snakes receive by mimicking coral snake will depend on the presence of coral snakes.

Both 1 and 2

AnswerA team of scientists designed an investigation that used artificial snakes to test the previous hypotheses. Which of the previous hypotheses are supported by the results displayed at the right?

Both 1 and 2

Interpreting Data

Biologists placed artificial snake mimics in two different localities to test the hypothesis that looking like a poisonous snake only works where the poisonous snake is found:1. Outside of the coral snake range—only king snakes present.2. Inside the coral snake range—both coral and king snakes are present.

Interpreting Data

The data graphed at the right __________ the hypothesis that the effectiveness of mimic coloration depends upon the presence of the poisonous model is:

supports does not support is irrelevant to

AnswerThe data graphed at the right __________ the hypothesis that the effectiveness of mimic coloration depends upon the presence of the poisonous model is:

supports

Interpreting Data

Based on this data which of the following is a logical hypothesis or prediction?

King snakes outside of the range of coral snakes will more closely resemble coral snakes than populations of king snake living within the range of coral .

King snakes outside of the range of coral snakes will not resemble coral snakes as closely as populations of king snakes that live within the range coral snakes.

Neither prediction is valid.

AnswerBased on this data which of the following is a logical hypothesis or prediction?

King snakes outside of the range of coral snakes will not resemble coral snakes as closely as populations of king snakes that live within the range coral snakes.