some properties of life
1) order
2) energy processing
3) response to environment
4) Reproduction/ Growth and Development
5) evolutionary adaptation
Order:
Life exhibits organization-it’s not random (at a cellular and molecular level) uses energy to create that order.
Energy Processing:
Organisms process energy to do their required jobs.
Response to Environment:
Respond to the environment and stimuli e.g. hares when temperatures get hot increase blood flow to ears to cool core body temperature.
Reproduction/ Growth and Development:
reproduce, grow and develop e.g. e.coli when dividing gives rise to e.coli, kids are like their parents —> bc of DNA organisms give rise to progeny that resemble themselves DNA determines the development of a specific organism.
Evolutionary Adaptation:
Over thousands of years changes occur that are hereditary that’s why they evolve and adapt to better suit their environment e.g. seahorse adapts to look like the coral environment.
2 reasons to classify life?
- social, dietary, cultural, medical, economic reasons.
2. to measure and monitor the diversity of life.
conservation biology
management of nature and biodiversity on earth. requires a detailed record of all forms of life.
- which species are extant, extinct, and lost to extinction.
classification of living things
1) physical structures
2) fossil record
3) genetic similarities
- Physical Structure:
not always reliable
- Analogous:
- Homologous:
Analogous:
not similar in anatomy but similar in function (wings of bats and birds) don’t have a common ancestor
homologous
same design, but different function, have a common ancestor (evolutionary relatedness of two structures)
Fossil Record:
not available for all organisms
- not available for every organism
- impossible to obtain DNA from most fossils
Genetic Similarities:
Much more accurate
- DNA changes but extremely slowly over centuries
-
Changes to DNA sequence overtime can be used as a
“molecular clock”
Cladogram:
A representation of relatedness (family tree).
Only shows the branching order, so you can draw it in many ways.
Phylogram:
A representation of relatedness where branch lengths are proportional to change ( DNA differences)
* When counting the units between each branch, only count vertical, not horizontal. * Height reflects the evolutionary distance.
Carolus Linnaeus
- Developed a hierarchy of groups, each one is a “taxon”
* Binomial system.
* Based on similarities/differences in physical characteristics of organisms
* Domain
* Kingdom
* Phylum
* Class
* Order
* Family
* Genus
* Species
acronym for taxonomy system by Linnaeus
Do Kings Play Chess Or Family Games Sometimes
Whole genome sequencing data suggests
that in the early evolution of the three domains, there was a lot of DNA exchanged between organisms.
Therefore, clear branches leading from one organism to another cannot always be established
Several possible mechanisms for exchanging DNA between organisms:
- Infectious elements bringing DNA from one organism to another.
- Possible fusion of organisms.
- Uptake of DNA released from dead organisms.
ring of life
No single common ancestor, but a community of primitive cells that exchanged DNA.
Early evolution gave rise to Archaea and Bacteria, and a fusion of these gave rise to eukaryotes.
Bacteria
- Small cells
* Most forms are singular
* Prokaryotic = lack a nuclear membrane surrounding their DNA
* One chromosome
* Chromosome is circular
* No membrane-bound organelles
* Most have a cell wall outside the cell membrane
* Cell wall contains peptidoglycan
* Membranes composed of unbranched fatty acid chains attached to glycerol by ester linkages.
* Asexual repoduction common (binary fission)
Eukarya
• Large cells
• Most forms are multicellular
• Eukaryotic = DNA bounded by nuclear membrane
• Genome consists of several chromosomes
• Chromosomes are linear
• Cell contains membrane-bound organelles (mitochondria)
• Have a cytoskeleton
• Not all of them have a cell wall, but for those that do, that wall contains no peptidoglycan.
• Membranes composed of unbranched fatty acid chains attached to glycerol by ester linkages.
• Sexual reproduction common, divide by mitosis and meiosis.
Most eukarya (some single celled) are visible to the naked eye.
