Prokaryotic Cell

•no nucleus•has cell wall

A review of what you’ve learned about cells and living organisms

Eukaryotic Cell

•has DNA contained in nucleus

Autotrophs capture the light energy from sunlight and convert it to chemical energy they use for food.

Heterotrophs must get energy by eating autotrophs or other heterotrophs.•Carnivores•Herbivores•Omnivores

Decomposers are heterotrophs that recycle dead organisms by breaking them down.

• Taxonomy is the science of grouping and naming organisms.

Groups organisms based on similarities

• Classification the grouping of information or objects based on similarities.

•We only know about a fraction of the organisms that exist or have existed on Earth.

•Taxonomists give a unique scientific name to each species they know about, whether it’s alive today or extinct.

•The scientific name comes from one of two “dead” languages – Latin or ancient Greek.

•Why use a dead language?

Devil Cat

Ghost Cat

Mountain Lion

Puma

Florida Panther

•There are at least 50 common names for the cat shown on the previous slides.

•Common names vary according to region.

•Soooo……why use a scientific name?There are about 1.5 million species already named

Scientists estimate between 2 and 100 million species that haven’t been discovered yet

Binomial Nomenclature

    •developed by Carolus Linnaeus

•a two-name system for writing scientific names.

•The genus name is written first (always Capitalized).     •The species name is written second (never capitalized).     •Both words are italicized if typed or underlined if hand written.

•Example: Felis concolor or F. concolor

1. Which is the genus? The species?

   

The major classification levels from most general to most specific (several of these have subdivisions)

•Linnaeus grouped organisms based on physical similarities•Today, organisms are grouped based on evolutionary characteristics

A group at any level is a taxon.

Kingdoms are divided into groups called phyla Phyla are subdivided into classes

Classes are subdivided into orders

Orders are subdivided into families Families are divided into genera Genera contain closely related species

Species is unique

Remember: King Philip came over for George’s sword.

Categories within Kingdoms

The Six Kingdoms and Domainsnumber of cells

energy cell type examples

Archaebacteria

unicellular some autotrophic, most chemotrophic

prokaryotic “extremophiles”

Eubacteria unicellular autotrophic and heterotrophic

prokaryotic bacteria, E. coli

Fungae most multicellular

heterotrophic eukaryotic mushrooms, yeast

Plantae multicellular

autotrophic eukaryotic trees, grass

Animalia multicellular

heterotrophic eukaryotic humans, insects, worms

Protista multicellular

heterotrophic or autotrophic

eukaryotic amoeba, paramecium, algae

The Dichotomous Key

• A key is a device for easily and quickly identifying an unknown organism.

• The dichotomous key is the most widely used type in biological sciences.

• The user is presented with a sequence of choices between two statements, couplets, based on characteristics of the organism. By always making the correct choice, the name of the organism will be revealed.

                                                         

   

1.  

A. one pair of wings

B. Two pairs of wings

Phylogeny, the evolutionary history of an organism, is the cornerstone of a branch of biology called systematic taxonomy.

Systematics, as systematic taxonomy is commonly called, is the study of the evolution of biological diversity.

                        

Modern Taxonomy

A phylogenetic tree is a family tree that shows a hypothesis about the evolutionary relationships thought to exist among groups of organisms. It does not show the actual evolutionary history of organisms.

Phylogenetic trees are usually based on a combination of these lines of evidence:

Fossil recordMorphology-deals with physical structures and organs (like arms)Embryological patterns of developmentChromosomes and DNA

Fossil

Morphology

homologous = same

These animals have evolved similar adaptations for obtaining food because they occupy similar niches. What can you infer about their phylogeny from their geographic locations?

Convergent Evolution

Analogous Structures  - 

•Traits that are morphologically and functionally similar even though there is no common ancestor.

Convergent evolution leads to……….

Embryology

Cladistics - is a relatively new system of phylogenetics classification that uses shared derived characters to establish evolutionary relationships.

A derived character is a feature that apparently evolved only within the group under consideration.

A phylogenetic tree based on a cladistic analysis is called a cladogram.

What derived character is shared by all the animals on the cladogram on the next slide?