Life & Classification Notes

Introduction This class is not just a “science” class. We will study living things. The branch of science that studies all the living things on Earth is called Biology.

Introduction continued In order to be considered living, an object must have or being able to do the following 6 things: 1.Have highly organized bodies with at least 1 cell 2.Can reproduce 3.Have genetic material 4.Can grow & develop 5.Have a metabolism 6.Can adapt & evolve

Cells A cell is a collection of molecules that are able to perform the functions of life

Reproduction Reproduction is the process where organisms create new, genetically similar, organisms to themselves

Genetic material Genetic material is a molecule that holds the information for making the traits of an organism

Grow & develop Growth is the process where living things increase in size Development is the process where living things get new body parts or abilities

Metabolism Metabolism is the set of chemical reactions in a living thing that either use or release energy

Adapt & Evolve Adapting is the process where organisms change their bodies or behavior based on their environment Evolution is the change in the genetics and characteristics of a species over time

Living or Non-living Test If an object has all 6characteristics, then it is considered an organism –An organism is a living thing –The term “biotic” is used to describe living things If an object is missing 1 or more characteristics, then it is considered non-living –The term “abiotic” is used to describe non- living things

Example 1 – Rye Grass  Has a cell  Can reproduce  Has genetic material  Grows & develops  Has a metabolism  Can adapt & evolve

Example 2 – Flu Virus  Has a cell  Can reproduce  Has genetic material  Grows & develops  Has a metabolism  Can adapt & evolve

Example 3 – Bread Mold  Has a cell  Can reproduce  Has genetic material  Grows & develops  Has a metabolism  Can adapt & evolve

Example 4 – Water  Has a cell  Can reproduce  Has genetic material  Grows & develops  Has a metabolism  Can adapt & evolve

Classification Classification is the process of grouping living things based on their similarities and differences The branch of science that deals with naming and classifying organisms is known as taxonomy Taxon (taxa-plural) is the generic term for any of the groups organisms are put into at any of the levels

Classification Which taxa an organism is placed into depends on its adaptations An adaptation is a body part or behavior that helps an organism live or reproduce

Taxa There is a hierarchy (series of levels) of groups (taxa) from broadest to most specific –The higher a taxon is on the list, the more organisms are in it –The lower a taxon is on the list, the fewer organisms are in it –The more taxa two organisms share, the more adaptations they have in common

Level of Classification Definition Domain A group kingdoms that have similar characteristics Kingdom A group of phyla that have similar characteristics Phylum A group of classes that have similar characteristics Class A group of orders that have similar characteristics Order A group of families that have similar characteristics Family A group of genera that have similar characteristics Genus A group of species that have similar characteristics Species A group of organisms that have many characteristics in common and are able to reproduce with each other and make fertile offspring

Facts about our system There are 3 taxa at the domain level There are 6 taxa at the kingdom level There are around 100 taxa at the phylum level There are thousands of taxa at the class level There are tens of thousands of taxa at the order level There are hundreds of thousands of taxa at the family level There are a few million taxa at the genus level There are between 8 & 10 million taxa at the species level (not including the ones for bacteria and archaea)

Full Classification Organisms get classified into a taxon (group) at each level of classification based on their adaptations Here’s how humans are classified… Level of Classification Taxon Characteristics members of that taxon share Other members of the taxon DomainEukarya Cells have a nucleus & other organized parts Algae, fungus, & plants KingdomAnimalia Bodies have more than one cell & ingest food Clams, starfish, insects, & worms PhylumChordata Have a spinal cord Fish, frogs, snakes, & birds ClassMammalia Have fur, feed milk to babies, control their own body temperature Whales, bats, mice, & elephants OrderPrimates 5 fingers/toes per hand/foot, opposable thumbs, large cerebellum (brain) Lemurs, monkeys, & baboons FamilyHominidae 32 teeth, limbs and hands/feet built for terrestrial life Chimps, gorillas, & orangutans GenusHomo Throat and brain built for complex language Homo neanderthalensis Homo erectus Speciessapiens Complex logical and abstract thought NONE

Problem with naming organisms #1 People in different countries speak different languages so their names for organisms are all different Could lead to confusion for scientists trying to share information

Solution to naming problem #1 Scientific names for organisms are all in Latin It’s fair because Latin is not spoken anywhere as a first language

Problem with naming organisms #2 The animal in the picture below is called all of the following names in the US: –cougar, –mountain lion, –puma, –Nittany lion, –Florida panther –catamount Different regions within the same country give the same organism different names.

Solution to naming problem #2 The animal in the picture below has the scientific name: Puma concolor Scientific names are unique to the organism. All organisms have 1 name & names are not used more than once

Problem with naming organisms #3 Some common names don’t accurately describe what the organism actually is Starfish, silverfish & jellyfish are not fish.

Solution to naming problem #3 Scientific names are usually descriptions of the characteristics of the organism Felis = cat silvestris = woodlands Felis silvestris = cat of the woodlands

Some people don’t follow the rules The scientist who discovers and describes a new organism gets to name it. –Some are named after themselves –Some are named after famous people –Some are named as a joke

Binomial Nomenclature Binomial nomenclature gives every organism a standard, 2-word, scientific name Rules for writing a scientific name: –First word is the genus name –Second word is the species name –First letter of the genus gets capitalized –First letter of the species is lower case –Whole name gets italicized when it is typed (or underlined when it is handwritten) Example for humans:

Identification and Classification There are 2 types of tools that can help scientists identify and classify organisms: –Dichotomous keys (also called taxonomic keys) –Field Guides They both have benefits and problems

Dichotomous (taxonomic) Key Characteristics given in pairs –Organism will either have one characteristic or the other Read both characteristics and either go to another set of characteristics OR identify the organism GOOD = organized and can be used forward and backwards BAD = can get pretty technical (need to know a lot about the organism’s characteristics)

Example Dichotomous Key 1a Tentacles present – Go to 2 1b Tentacles absent – Go to 6 2a Eight Tentacles – Octopus 2b More than 8 tentacles – Go to 3 3a Tentacles hang down – Go to 4 3b Tentacles upright – Sea Anemone 4a Balloon-shaped body – Jellyfish 4b Body NOT balloon-shaped – Go to 5

Field Guide Book of pictures of different organisms Match the characteristics of the organism you are trying to identify to the characteristics of the organisms in the pictures GOOD = don’t have to know anything other than what the organism looks like BAD = takes a long time and easy to miss small differences between organisms

Example Field Guide