Classification

Biodiversity – the variety of organisms in an ecosystem. 10,000,000+ species known to exist today. Possibly 30,000,000+ species of insects alone. Relationship between organisms determined by: Evolutionary relationship Biochemistry Behavior Developmental stages

Classification 8 Levels of classification in modern system. There used to be 5 levels in the original Linnaeus system Each level is called a taxon and can change as more information becomes available. Can be used to classify all BUT asexually reproducing species 1. Domain (largest category, organisms are least similar) 2. Kingdom 3. Phylum 4. Class 5. Order 6. Family 7. Genus (smallest category, organisms most similar) 8. Species (down to a single organism!) Saying for remembering this is?

Which is more closely related to the …

Domain – broadest level, includes 3 lineages: 1. Archaea: similar to Bacteria, but inhabit extreme hostile environments (hot springs, deep-sea thermal vents, salty lake, no O2). “Ancient” 2. Bacteria: unicellular prokaryotic organisms. Lack organelles and nucleus. Has a cell wall. 3. Eukarya: multicellular eukaryotic organisms. Has organelles and a nucleus. “True nucleus”.

Kingdoms 6 different kingdoms in modern system Used to be 5 because … Archaebacteria & Eubacteria used to be 1 kingdom known as Monera.

6 Kingdoms Kingdom Eubacteria Bacteria Archaebacteria Protista 1 cell organisms with nucleus Fungi Yeasts, molds, mushrooms (Do Not make own food like plants) Plantae All Plants Animalia All Animals

Kingdom Archaea (Domain Archaea) Prokaryotic – no nucleus or membrane bound organelles Used to be in Kingdom Monera with bacteria Unicellular and microscopic Live in extreme environments (Salty lakes and boiling hot springs)

Kingdom Bacteria (Domain Bacteria) Prokaryotic – no nucleus or membrane bound organelles Used to be in Kingdom Monera with archaea Unicellular and microscopic Can be a PRODUCER Normal bacteria GRAM STAIN Used to differentiate between different types of bacteria (Gram + or Gram -) FACT Penicillin kills bacteria by stopping their production of their cell walls

Kingdom Protista (Domain Eukarya) Eukaryotic – nucleus and membrane bound organelles Diverse collection of mostly single celled organisms Can be “animal like” or “plant like” Algae is an example of plant like (is autotrophic – photosynthesis) – these are PRODUCERS Animal like protists are called protozoans Recent evidence suggests this kingdom should be split into multiple kingdoms

Kingdom Fungi (Domain Eukarya) Eukaryotic - nucleus and membrane bound organelles Multicellular Includes mushrooms, molds, yeasts Mode of nutrition Heterotrophic - Mostly decomposers (break down remains of dead organism and organic wastes, such as leaf litter and animal feces, and absorb the nutrients into their cells)

**Additional Info about the Kingdom Fungi not on note handout Produce spores that can survive for very long periods of time in unfavorable conditions and will wait to sprout until conditions are favorable for the adult fungi to survive Have a branching network called hyphae that work with their roots to digest the surface they are growing off of Have a cell wall NOT composed of cellulose Some of them can produce toxic chemicals

Kindgom Plantae (Domain Eukarya) Eukaryotic - nucleus and membrane bound organelles Multicellular Plants Nonmotile Special Organelles (that animals don’t have) – 1) Cell walls made of cellulose, 2)Chloroplast, 3)Central vacuoles Mode of Nutrition Autotrophic - Produce own food through photosynthesis

Kingdom Animalia (Domain Eukarya) Eukaryotic - nucleus and membrane bound organelles animals Multicellular Motile Lack rigid cell walls, chloroplasts, and central vacuoles Mode of nutrition Heterotrophic – eat different organisms for food

VIRUSES Viruses are considered NON-LIVING because they are not made of cells. So, what kingdom would they be classified in? More facts about viruses: Require a host to reproduce Made only of protein and DNA No known cures for human viruses. If you get one, you will have it for life.

Taxonomy – science classifying organisms. (Systematics is classifying organisms based off of their evolutionary history) Aristotle (about 2,400 years ago) 1st scientist to classify organisms Only two groups (plant & animal) based on habitat and stem structure. Common names & long descriptions Carolus Linnaeus (year 1735) “father of modern taxonomy” Based on structural similarities. Originally has 5 levels of classification. Used 2 name naming system (binomial nomenclature)

Binomial nomenclature – 2 name naming system. “Genus & species” First word capitalized, second word not. Always italicized or underlined. Always in Latin because… Dead language (not subject to change in meaning “slang”) It is universal Example: Homo sapien or Homo sapien

Dichotomous key "divided into two choices“ looks at the similarities and differences leads the user to the organism’s name MONEY TAXONOMIC KEY 1 A. Metal....................................................go to 2 1 B. Paper....................................................go to 5 2 A. Brown (copper)........................................penny 2 B. Silver....................................................go to 3 3 A. Smooth edge...........................................nickel. 3 B. Ridges around the edge...............................go to 4 4 A. Torch on back..........................................dime 4 B. Eagle on back...........................................quarter 5 A. Number 1 in the corners...............................$1 bill 5 B. Number 2 in the corners...............................$2 bill

Problems with Taxonomy Classifying species into higher taxa is useful, but ultimately arbitrary Higher classification levels are defined by various morphological characteristics instead of measurable differences that could be used to apply to an entire taxon level Therefore, many biologists now propose that classification be based solely off the evolutionary history of an organisms

Classifying organisms based on Evolution Phylogeny – the evolutionary relationship between organisms. Cladogram / Phylogenetic Tree- looks like family tree, used to show evolutionary history of organisms Evidence of shared ancestry: Fossil records Homologous features Embryological evidence

Analogous structures - traits that have similar use, but different structure. Due to structure being used in similar way Homologous structures – traits that have similar structure, but have different uses. Due to common ancestry.

Cladistics (Cladograms) Organisms are grouped into clades A clade is a group of species that includes an ancestral species and all of its descendants Based on a new trait developing and being passed down to descendants Groups of organisms that share these new traits are more closely related to each other than to groups who only have ancestral traits

Making Cladograms / Phylogenetic Trees Shared derived characters – new traits that are shared by a group These shared derived characters distinguish between clades and are “branches” in the tree of life (and branches in cladograms) Shared ancestral characters – original traits present in ancestral groups

Making Cladograms / Phylogenetic Trees – Character Tables Character Table - Table used to generate phylogenetic trees by comparing characteristics as species. Each new character represents the divergence of two groups from a common ancestor (one without the new characteristic and one with it) and thus shows the order in which new traits evolved Ingroup – group of taxa that is actually being analyzed Outgroup – species or group of species that is known to have diverged before the lineage that contains the groups we are studying

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