Slide shows Unit 1 Flashcards
Biodiversity
- Refers to the diversity of all life
• The number and variety of genes, species, and
ecosystems on Earth
Species
A group of organisms that can interbreed in
nature and produce fertile offspring.
Identifying & Naming New Species
Scientists have been unable to agree on a single definition
of what a species is.
Morphological Species Concept:
focuses on morphology
(structure or form of organisms) – body shape, size, and
other structural features
Biological Species Concept:
defines species on the basis
of whether two organisms can produce fertile offspring
Phylogenetic Species Concept:
examines the phylogeny
(evolutionary history) of organisms.
Naming Species System
A standard system for naming organisms is needed
that will be understood by any scientist, anywhere in
the world.
Taxonomy
is the branch of biology that identifies,
names, and classifies species.
binomial nomenclature
- Swedish scientist Carl Linnaeus
developed a system for naming
species
Binomial → something with two parts
Nomenclature → naming system
Hierarchical classification
The method of classifying organisms in which species
are arranged in categories from most general to most
specific (nested classification).
A species is classified by assigning it 8 nested categories
Domain→Kingdom→Phylum→Class→Order→Family→Genus→Species
RANK
Domain→Kingdom→Phylum→Class→Order→Family→Genus→Species
taxon (sg.) or taxa (pl.)
The NAME of each rank
Examples: Mammalia (name of a class)
Rodentia (name of an order)
Shared Evolutionary History
Main goal of modern taxonomy is to determine the shared evolutionary history of groups of organisms • Biologists assume the greater the shared evolutionary history between organisms, the more closely related they are • We use evidence from Anatomy, Physiology and DNA to determine relatedness
common
ancestor
If two species share much of the same evolutionary
history, it means they have a fairly recent
Ancestor
an organism (or organisms) from which other groups of organisms are descended
Anatomy
is the study of the structure and form,
including internal systems of organisms.
Uses anatomical evidence from living species to determine relationships
among organisms
• Ex. Bone structure may indicate a shared evolutionary history
• Over millions of years, the size and proportions of the bones have been
modified for different purposes (swimming, running, flying). However, the
overall arrangement indicate a shared evolutionary history
Physiology
is the study of the physical and chemical
functions of organisms (how they work)
• Scientists study the biochemistry of organisms and
compare structures such as parts of cells, tissues, and
proteins.
• The organism’s physiology is ultimately controlled by it’s
genes
DNA Evidence of Relationships
- Genetic analysis • Genes are sections of DNA that code for making proteins • The degree of genetic similarity is determined by the number of genetic sequences two individuals have in common • DNA (genetic) evidence suggests that fungi are more closely related to animals than to plants.
Phylogenetic Tree
evolutionary history of a species, shows the
proposed amount of time
Cladogram:
a simplified branching diagram used to show
the relationships among species.
branches represent a sequence of events
with progressive evolutionary traits.
– Root represents the common ancestor
– Closely related organisms are classified together with all the
other organisms that share a common ancestor
clade
These related organisms are placed in the same
monophyletic group called a clade
