Upload
ann-rose
View
213
Download
0
Embed Size (px)
Citation preview
What we need to learn How and why organisms are hierarchically classified
and based on evolutionary relationships
Learn the reasons for changes in how organisms are classified
Learn the distinguishing characteristics of the domains and kingdoms of living organisms
Classifying Organisms One branch of biology investigates biodiversity
The variety of organisms considered at all levels from populations to ecosystems
Every year scientists find new species and try to classify them in a meaningful way
This species has scales and a stinky tongue to catch ants
What species would you group this with?
Taxonomy The science of describing, naming, and classifying
organisms is called Taxonomy
Any particular group within a taxonomic system is called a
Taxon
Taxonomy Early work to classify organisms only looked at their
life on land or in water
As more species were named, this system became inadequate
Common names were widely used but ran into issues Some common names don’t truly identify the species
The Linnaean System Carolus Linnaeus developed a
system to categorize according to form and structure
Levels of Classification The modern version of Linnaeu’s system
Binomial Nomenclature Scientific name Latin Starts with with genus name Followed by species identifier
Homo sapiens Homo-genus Sapiens-species
Levels of classification Name of species is often very descriptive
Always capitalize first name, lower case second. ALWAYS italicize the names
Subspecies names are often needed When the same species lives in different geographic areas
Terrapene carolina triunui is a subspecies of Terrapene carolina
Phylogenetics We have already learned this
Phylogenetic trees? Remember?
Phylogenetics The analysis of the evolutionary or ancestral
relationships among taxa
Evidence of Shared Ancestry
Remember homologous and analogous structures? YOU BETTER!
Systematics use homologous structures
Analogous structures and misidentify species
Pangolins and dogs have similar jaw structures We therefore classify them with dogs
If we classified them based on their scales, what would we classify them with?
Cladistics Cladistics-a system of phylogenetic analysis that
uses shared and derived characteristics as the only criteria for grouping taxa
Shared characteristic- a feature that all members of a group have in common Hair in mammals Feathers in birds
Derived characteristics- features that evolved only within the group under consideration
Cladistics Clade- the group of organisms that includes an
ancestor plus all its descendants
Cladograms-diagrams that show clades and characteristics
Three Domains of Life Domain Bacteria
Small single celled prokaryotic organisms
Have a cell wall, plasma membrane, cytoplasm that lacks complex organelles
Reproduce by cellular fission
No membrane bound DNA, therefore no nucleus
Three Domains of Life Domain Archea
Consists of prokaryotes Distinctive cell membranes Some are autotrophic, and produce food by
chemosynthesis Some produce flammable gases, such as methane Many inhabit harsh environments Scientists think archea were among the earliest
organisms on Earth Archaea and bacteria have possible coevolved
Three Domains of Life Domain Eukarya
Most familiar group Consists of eukaryotic
organisms Large cells that have
true nucleus and complex cellular organelles
Plants Animals
The Six Kingdoms Archaebacteria
Literally means “ancient bacteria” So different from bacteria now, scientists only use
“archaea” to name them
The Six Kingdoms Protista
First of 4 eukaryotes Called protists Defined as those eukaryotes
that are not plants, animals, or fungi
Most are unicellular Scientists actually think the
kingdom “Protista” is no longer useful. Most protista are not related to each other
Amoebas and paramecia Some seaweed and molds
The Six Kingdoms Fungi
Eukaryotic Heterotrophic Unicellular, multicellular Fungi absorb nutrients rather than ingest them 70,000 species of fungi
The Six Kingdoms Plantae
Eukaryotic Multicellular Besides some parasitic
plants, most are autotrophic Use photosynthesis as a
source of energy Develop from embryos Most live on land Mosses, ferns, flowering
plants