Taxonomy
classification (grouping) and naming living things
Species Concept
basic group - interbreed in nature and produce fertile offspring
Variation in species
genetic differences between species supplies material for evolution.
Polymorphism
The differences between males and females of the same species, the two colors of moth.
Geographic variation
occurs when a species occupies a large geographic range that includes distinct local environments. Populations in those local environments often have unique physical characteristics
Individual variation
occurs in all populations of organisms that reproduce sexually(independent asst., crossing over )
Species remain separate/Species concept
don't mix genes
Potential mates don't meet in the wild
the grizzly bear and the polar bear reproduced together in captivity, no hybrids have been discovered in the wild because they live in different places and eat different kind of food.
Potential mates meet but don't breed
a giraffe and an ostrich cannot mate even though they may come in contact with each other. These species are too different to breed together.
Potential mates meet, breed, but not viable
The dog and coyote meet and breed but their offspring may be sterile (incapable of reproducing). The mule, a cross between a horse and a donkey, is almost always sterile.
Limitations of the Species Concept
Does not apply well to organisms that reproduce asexually.
Some populations are intermediate between species.
Does not take into account slow unmeasurable changes that occur in species through time.
Ex. Some hybrids between species are viable and fertile,
Intermediate species
are those on the way to being separate species. They are separate breeding populations, but they are still similar enough to breed with each other. Same species ? Intermediate species ? Separate species.
All organisms change to suit their environment, and
Classification of homologies
grouping based on commonalities
Uses of classification of homologies
Make sense of diversity
Identify new alleles to form better crop plants, or control of unwanted species
Disease control by identification of disease carrying organisms
Identify essential ecological organisms - to maintain habitats
Provide an understanding
Taxonomy may be based on
Biochemistry - amino acids, proteins, DNA
Behavior
Structure - not those that change like size or color
Homologous structures
show ancestry, same internal structure,
different function
Ex - bat wing, human arm, whale fin
Analogous structures
no ancestry - similar appearanc and function but structurally different
Linnaean Classification
Domain - related kingdoms
Kingdom - (largest, most diverse)
Phylum
Class
Order
Family
Genus
Species - interbreed and produce fertile offspring (smallest, least diverse)
Each taxa unique
Fixed number of taxa
Group species based on similarities in physical
Binomial nomenclature-naming living things
scientific names, used all over world
1st name =
genus name
2nd name =
species within genus
Binomial nomenclature
First name
Capitalized
Refers to "genus"
Second name
Small letters (apparently they don't say lower case)
Refers to "species" (this is sometimes followed by the last name of the person who first published the name, and the date of publication - Equus zebr
Ways to classify
A) Orthodox -
organisms divided by anatomical similarities.
Problem as technology increased have more structures available to classify with
B) Phenetics -
compare organisms on as many traits as possible and measures degrees of similarity and depicts evolu
Cladistics
is a method of hypothesizing relationships among organisms. Assumes each group has an ancestor that other species don't share. A cladogram is comprised of branches and nodes, a node is the location where the cladogram branches. When a line branches at a n
Phylogenic Classification
All levels equal
No limit on levels
Show evolution
Shows organisms related by ancestry
No naming method
Kingdom Monera
Prokaryotic ,most unicellular or colonial
asexual or sexual
autotrophs, chemosynthetic, heterotrophs
1) Eubacteria -
true bacteria
2) Archaea bacteria -
ancient bacteria
Kingdom Protista
Eukaryotic, most unicellular some multicellular (kelp)
most diverse kingdom, consumers, producers and decomposers
Ex - algae, protozoa
VERY DIVERSE
Kingdom Fungi
molds, yeasts, mushrooms
Eukaryotic, most multicellular (yeast = unicellular)
most heterotrophs, decomposers (secrete enzymes to digest food then absorb it),
sexual or asexual
cell walls of chitin
Kingdom Plantae
mosses, liverworts, ferns, seed plants.
Eukaryotic, multicellular, autotrophs (rare heterotrophs), sexual & asexual,
develop from embryo
cell wall of cellulose,
complex tissue & organ structure, store food as starch, have chloroplast, most live on land.
Kingdom Animalia
Eukaryotic, multicellular, heterotrophs (ingestion)
develop from embryo,
diverse forms and size, mainly sexual, no cell wall,
complex tissue, organ, organ system structure, land & water