Biology: classification and taxonomy Flashcards
how old is earth?
4.6 billion years
radiometric dating
uses radioactive decay to determine age
atomic number
number of protons in element
isotope
Same element (same # protons), different # neutrons, so different Atomic Mass
radioactive decay
nuclei releases energy until stable
half life
time it takes for ½ unstable isotope to become stable
By comparing ratio of stable isotopes to unstable isotopes, can determine age
radiometric dating
determines half life
biogenesis
All living things come from other living things
Abiogenesis/spontaneous generation
Living things arise from non-living things
when did Small organic molecules synthesized
3.8 billion years
Oparin
Haldane hypothesis about young earth: •Probably H2, NH3, CH4, H2O •NO FREE OXYGEN! •Lots of energy from UVs & lightning •Energy + chemicals + reducing organic soup of small molecules
Miller-Urey Experiment
H2O + H2 + CH4 + NH3 + spark (lightning) 5 some amino acids. + precursor to adenine
Joining of small molecules into polymers
Polymers formed include proteins & nucleic acids
Experiment: Drip solution of amino acids on hot clay, sand, or rock 5polymers
Packaging of molecules
Organic molecules become surrounded by membrane-like structure
Experiment: Combine organic molecules in flask and see what happens
• Lipids spontaneously form spheres called liposomes
• Form membrane around proteins and nucleic acids
RNA is first hereditary material
RNA evolved before DNA
Many hypothesis re: how RNA evolved
Experiments: Put nucleotides in test tube 5 short RNA polymers
More evidence: Ribozymes -
RNA that can copy itself, chop itself up and make more RNA
How did life evolve?
- Anaerobic heterotrophic prokaryotes form from Organic soup
- Due to a mutation, chemosynthetic autotrophic prokaryotes evolve
- Due to mutation, photosynthetic autotrophic prokaryote
- Oxygen and the ozone layer formotes evolve
- Eukaryotes and aerobic organisms form from endosymbiosis
How did life originate?
- Small organic molecules synthesized
- Joining of small molecules into polymers
- packaging of molecules
- RNA is first hereditary material
anaerobic
does not need oxygen to live
prokaryotes
do not have nucleus or organelles
heterotroph
Organism that eats other organisms for energy
Chemosynthetic
Use energy from chemicals to make food (carbohydrates)
Autotroph
Makes food from non-living things
Photosynthetic
Use energy from sun to make food (carbohydrates)
First toxic waste
O2 accumulation causes destruction of sensitive organic molecules, causing
starvation of many heterotrophs
Biodiversity
Variety of organisms within a given ecosystem, biome, population
Taxonomy:
Science of grouping organisms by their characteristic
how do we organize biodiversity
Nutritional Mode
Structure and Function
Molecular similarities and common ancestors
Chemosynthesis
Making food using chemicals in the environment
Photosynthesis
Making food using light energy
Decomposers
Organisms that absorb nutrients from dead organisms
Heterotrophs
Organisms that cannot make their own food and must ingest it
Autotrophs
Organisms that make their own food by chemosynthesis or photosynthesis
Linnaean System
Uses Binomial nomenclature to identify organisms
First word: genus - capitalized & italics
Second word: species - not capitalized & italics
Genus groupings
Species that are closely related are grouped into the same genus
Organisms are organized into eight groupings (taxa)
Domain Kingdom Phylum Class Order Family Genus Species
Domain Bacteria
Prokaryote, cell wall, plasma membrane, circular chromosome
• No organelles, no nucleus
• Autotrophs or heterotrophs
Domain Archaea
Same as bacteria EXCEPT different molecules in cell wall and plasma membrane.
• Live in extreme environment
Domain Eukarya
True nucleus, complex organelles
Six Kingdoms
Eubacteria
- Archaebacteria
- Protists
- Plants
- Fungi
- Animals
Archaebacteria are:
Prokaryote • Unicellular • Autotrophs or heterotrophs • Live in extreme environments - high heat (thermophiles) - high salt (halophiles)
Eubacteria are:
Prokaryote • Unicellular • Autotrophs or heterotrophs • No organelles - have cell membrane - have DNA
Protists are:
Eukaryotes
• Unicellular
• Autotrophs or heterotrophs
• Not animal, plant or fungi
Fungi are:
Eukaryote
• Mostly multicellular
• Heterotrophs (absorb food
Plants are:
Eukaryote
• Mostly multicellular
• Autotrophs
Animals are:
Eukaryotes
• Multicellular
• Heterotrophs
Cladistics
Grouping organisms by molecular similarities & common ancestors
•Work in progress…always be updated
• Groups species based on order in which they diverged from common ancestor
• Utilizes derived characteristics
Derived characteristic
Feature that evolved only in group of interest
Cladograms
Branching diagram showing the cladistic relationship between species.
• Vary based on trait being examined