4.3 Classification and evolution Flashcards
why do we classify organisms
- more convenient
- to make the study of living things more manageable
- to make it easier to identify organisms
- to help see the relationships between species
what are organisms classified into
domain kingdom phylum class order family genus species
what are the 3 domains
archaea
eubacteria
eukaryote
what are the 6 kingdoms
archaebacteria eubacteria plants animals fungi protoctists
how are organisms sorted into the phylum category
organisms which have the same body plan (possession of backbone)
how are organisms sorted into the class category
possess same general traits (no. of legs)
how are organisms sorted into the order category
subdivision of class (omnivore, herbivore, carnivore)
how are organisms sorted into the family category
group of closely related genera
how are organisms sorted into the genus category
group of closely related species
how are organisms sorted into the species category
basic unit of classification- sorted by variation
describe the binomial naming system
- used to name organisms
- genus (capital letter) and species (lowercase) name are used
- must be underlined
- in latin so its universal
why does using a common name for organisms not work well
- different countries call organisms differently
- some organisms may have different common names in diff parts of a country
- translation of languages may give different names
- same common name may be used for different species in different parts of the world
define the biological definition of species
a group of organisms that can freely interbreed to produce fertile offspring
define the phlylogenetic definition of a species
a group of individual organisms that are very similar in appearance, anatomy, physiology, biochemistry and genetics
describe the features of archaea and eubacteria
- no nucleus
- have loop of DNA
- naked DNA
- no membrane bound organelles
- smaller ribosomes
- smaller cells than eukaryotes
- may be free living or parasitic
describe the features of protoctists
- eukaryotic
- mostly single-celled
- show wide variety of forms
- show various animal/plant-like features
- mostly free living
- have autotrophic or heterotrophic nutrition
define autotrophic and heterotrophic
auto- can photosynthesise
hetero- can break down large molecules
describe the features of fungi
- eukaryotic
- exist as single cells or have mycelium that consist of hyphae
- walls made of chitin
- cytoplasm is multinucleate
- mostly free living and saprophytic(cause decay or organic matter)
describe the features of plants
- eukaryotic
- multicellular
- cells surrounded by cellulose cell wall
- autotrophic
- contain chlorophyll
describe the features of animals
- eukaryotic
- mulyicellular
- heterotrophic
- usually able to move around
what did Linnaeus use to classify organisms
observable features
what can we now use to classify organisms
biological molecules (cytochrome C) DNA
how can we use cytochrome C to classify organisms
-its a protein found in respiration
-not identical in all species
If we compare the sequence of amino acids in cytochrome C of 2 species:
=sequences the same, must be closely related
=sequences different, not closely related
=the more differences in sequence, the less closely related