Introduction to living things and their components Flashcards
Organization at a molecular, cellular, and organic level
Property of life- Order
Nectar supplies birds with chemical energy for flight and other work
Property of life- Energy processing
Stimulus of fly landing on Venus fly trap to close
Property of life- Response to environment and stimuli
Gradual changes from mutation, natural selection
Property of life- Evolutionary adaptation
DNA determines the development of a specific organism
Property of life- Growth and development
Living things produce offspring that are similar to themselves
Property of life- Reproduction
Similar in anatomy
Similar or dissimilar function
Inherited from a common ancestor
Homologous structures
Not similar in anatomy
Similar in function
Not inherited from a common ancestor
Analogous structures
Fossils can help establish ancestry,
- not available for every organism
- difficult/impossible to obtain DNA evidence from most fossils
Fossil record
DNA and protein sequences change over time
- When two organisms evolve from a common ancestor they slowly
accumulate sequence differences
- The number of sequence differences can reveal how related two
organisms are
Genetic similarities – much more accurate
a representation of
relatedness (“family tree”)
Cladogram
a representation of
relatedness where branch lengths
are proportional to change (e.g.
DNA differences)
Phylogram
developed a hierarchy of groups, each one is a “taxon”
Classification of Living Things = Taxonomy
binomial system
Classification of Living Things = Taxonomy
based on similarities/differences in physical
characteristics of organisms.
Classification of Living Things = Taxonomy
Domain
o Kingdom
o Phylum
o Class
o Order
o Family
o Genus
o Species
Classification of Living Things = Taxonomy
Carolus Linneaeus (1707-1778):
Classification of Living Things = Taxonomy
Three domains of life (Woese, 1990)
EUKARYA, ARCHAEA, BACTERIA
Whole-genome sequencing data suggests that in the early evolution of the
three domains, there was a lot of DNA exchanged between organisms
Lateral transfer
-infectious elements
bringing DNA from one
organism to another
Several possible
mechanisms
possible fusion of
organisms
Several possible
mechanisms
uptake of DNA released
from dead organisms
Several possible
mechanisms
An alternative model to the ”tree” to explain the early history of life
“Ring” of Life
No single common
ancestor, but a
community of primitive
cells that exchanged DNA
“Ring” of Life
Early evolution gave
rise to Archae and
Bacteria, and a fusion
of these gave rise to
Eukaryotes
“Ring” of Life
small cells (1-10 μm)
Bacteria
most forms are singular
Bacteria
prokaryotic = lack a nuclear membrane surrounding their DNA
Bacteria
one chromosome (forms a nucleoid)
Bacteria
chromosome is circular
Bacteria
no membrane-bound organelles
Bacteria
most have a cell wall outside the cell membrane
Bacteria
cell wall contains peptidoglycan
Bacteria
membranes composed of unbranched fatty acid chains
attached to glycerol by ester linkages
Bacteria
asexual reproduction common (binary fission)
Bacteria
large cells (100 - 1000 μm)
Eukarya
most forms are multicellular*
Eukarya
eukaryotic = DNA bounded by nuclear membrane
Eukarya
genome consists of several chromosomes
Eukarya
chromosomes are linear
Eukarya
cell contains membrane-bound organelles (e.g.,
mitochondria)
Eukarya
have a cytoskeleton
Eukarya
not all have a cell wall, but for those that do, that
wall contains no peptidoglycan.
Eukarya
membranes composed of unbranched fatty acid
chains attached to glycerol by ester linkages
Eukarya
sexual reproduction common, divide by mitosis
and meiosis
Eukarya
relatively small cells (1-15 μm)
Archaea
most forms singular
Archaea
prokaryotic = lack a nuclear membrane surrounding their DNA
Archaea
one chromosome (forms a nucleoid)
Archaea
chromosome is circular
Archaea
no membrane-bound organelles
Archaea
most have a cell wall outside the cell membrane
Archaea
cell wall does not contain peptidoglycan
Archaea
membranes composed of unusual lipids, e.g., branched
hydrocarbon chains attached to glycerol by ether linkages.
Archaea
asexual reproduction common (binary fission)
Archaea
- often live in extreme environments (e.g., extreme halophiles, and
hyperthermophiles).
Archaea
Archaea, Bacteria, Eukarya
Domain
Plantae, Animalia, Fungi, Protista,
Eubacteria, Archaebacteria
Kingdom
the most specific level. These organisms are so
similar that they can mate and reproduce with each other.
Species
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