Classification and Diversity Flashcards
Organisms can be classified based on _________ _______
Physical similarities
Who developed the scientific naming system still used today?
Linnaeus
This is a group (level) of organisms in a classified system
Taxon
Two part naming system
Binomial nomenclature (the two parts are genus and species)
Species in the same genus are thought to be _________ ________
Closely related
Genus name is always _______
Capitalized
This is the second part of a scientific name, is always lowercase, and always follows genus
Species
How many levels does Linnaeus’ classification system have?
Seven (even level includes the level above it)
Why does the Linnaean classification system have limitations?
It doesn’t account for molecular evidence and is based on only physical similarities
What is modern classification based on?
Evolutionary relationships
What is classification based in common ancestry?
Cladistics
The evolutionary history for a group of species, (evidence, fossil record, molecular data)
Phylogeny
What is an evolutionary tree made using cladistics?
A cladogram
This is a group of species that shares a common ancestor
Clade
Traits shared in different degrees by clade members
Derived characters
More closely related species share more ________ _______
Derived characters
These represent the most recent common ancestor of a clade
Nodes
Molecular evidence reveals ________ ________
Species’ relatedness
These provide clues to evolutionary history by using mutations to estimate time
Molecular clocks
Mutations add up at ______ ________ _______ in related species
A constant rate
As more time passes, more ______ will take place
Mutations
Scientists estimate mutation rates by _______ ________ _______ _____ ________ ______
Linking molecular data and real time
Mitochondrial DNA and ribosomal RNA provide _____________
Two types of molecular clocks
Different molecules have different _________ ________
Mutation rates
A higher mutation rate means better studying ____________ __________ _________
Closely related species
A lower mutation rate mean better for studying ________ _______ ______
Distantly related species
What is used to study closely related species
Mitochondrial DNA because mutation time is ten times faster than nuclear DNA
This is passed down unshuffled from mother to offspring
Mitochondrial DNA
This is inherited from both parents, making it more difficult to trace back through generations
Nuclear DNA
This is used to study distantly related species
Ribosomal RNA because it’s mutation rate is lower than most DNA
How many domains does the current tree of life have?
Three
What are the three domains in the tree of life?
Bacteria
Archaea
Eukarya
Domains are all above ______
The kingdom level
Who proposed the tree of life?
Carl Woese based on his rRNA studies of prokaryotes
One of the largest groups on earth, classified by shape, need for oxygen, and diseases caused
Domain bacteria
Cell walls chemically different from bacteria, differences discovered by studying RNA, known for living in extreme environment
Domain archaea
What kingdoms does Domain Eukarya contain?
Includes Kindom Protista, Plantae, Fungi, and Animalia
Why are bacteria and archaea hard to classify?
They transfer genes among themselves outside of reproduction and it blurs the lines between species
Any plane passing through center; divides body into mirrored halves
Spherical symmetry
Body divided into similar halves by more than 2 planes passing though longitude axis
Radial symmetry
Found chiefly among some unicellular forms; ground in shape, no distinct top or bottom
Spherical symmetry
Free floating or weakly swimming animals, distinct top and bottom; no anterior or posterior end; can interact with environment in all directions
Radial symmetry
Random, having 2 sides that are not the same
Asymmetrical
Organism can be divided along the sagittal plane into two mirror portions; right and left halves; much better fitted for directional (forward) movement
Bilateral symmetry
Associates with cephalization, differentiation of a head region with concentration of nervous tissue and sense organs
Bilateral symmetry
Anterior (cranial)
Head end
Posterior (caudal)
Tail end
Dorsal
Backside
Ventral
Front or belly side
Medial
Midline of body
Lateral
Sides
Distal
Parts father from the middle of the body
Proximal
Parts are nearer to the middle of the body
Frontal plane (coronal plane)
Divides bilateral body into dorsal and ventral halves
Sagittal plane
Divides body into right and left halves
Transverse plane (cross section)
Divides body into anterior and posterior portions
