3. Classification And Evolution Flashcards
Need for classification
- for convenience
- Makes it easy to identify organisms
- Makes it easier to study organisms
- Allows us to see the relationships between organisms
Classification top to bottom
Domain, kingdom, phylum, class, order , family, genus, species
Domain
(archaea, eubacteria, eukaryotae)
Kingdom
plantae, animalia, fungi, protoctista, prokaryotae)
Phylum
whether or not they have a backbone) chordata = animals w/ backbones
Class
general traits e.g. number of legs + arms)
Order
depends on what they eat)
Family
closely related group within order)
Species biological definition
a group of organisms that can interbreed to produce a fertile offspring =
Phylogenetic definition of species
a group of individual organisms that are very similar in appearance, anatomy, physiology, biochemistry and genetics
Features of protoctista
- eukaryotic
- Aquatic
- Most unicellular
- Autotrophic or heterotrophic
Plant responses to defend themselves from herbivores:
- chemicals (phenols)
- Folding
- Stings
Autotroph
make their own nutrients
Heterotroph
organisms that eats other plants or animals for energy and nutrients
Q
Binomial naming system
- first name is always the genus
- Second part of the name is the species
- The first letter in the genus is a capital letter and the species is in lower case (it all is in italics) = allows everyone to use the same naming system which simplifies research
Advantage of binomial naming system
universal and helps know which genus it belongs to
Prokaryotae
have no nucleus
have a loop of DNA that is not arranged in linear chromosomes
• have naked DNA (DNA that is not associated with histone proteins)
• have no membrane-bound organelles
• have smaller ribosomes than in other groups
• have cells smaller than those of eukaryotes
• may be tree-living or parasitic (some cause diseases)
Protoctista
• are eukaryotic
• are mostly single celled (but many algae are multicellular)
• show a wide variety of forms (the only thing that all protoctists have in common is that they do not qualify to belong to any of the other four kingdoms!)
• show various plant-like or animal-like features
• are mostly free-living
• have autotrophic or heterotrophic nutrition - some photosynthesise, some ingest prey.
some feed using extracellular enzymes (like fungi do), and some are parasites
Fungi
• are eukaryotic
• can exist as single cells (called yeasts) or they have a mycelium that consists of hyphae
• have walls made of chitin
• have cytoplasm that is multinucleate
•are mostly free-living and saprophytic - this means that they cause decay of organic matter
Plantae
• are eukaryotic are multicellular
have cells surrounded by a cellulose cell wall
• are autotrophic (absorb simple molecules and build them into larger organic molecules)
• contain chlorophyll
Animalia
• are eukaryotic are multicellular
• heterotrophic (digest large organic molecules to form smaller molecules for absorption)
• are usually able to move around
How is genetic material in bacteria held?
- dna loop free in cytoplasm
- Not associated w histone
Defining features of eukarya
- nucleus
- DNA w histone
- Membrane bound organelles
Evidence to classify organisms
DNA, biological evidence, conversion evolution
Conversion evolution
concept of organisms from different species could adapt in similar ways and therefore look similar
Biological evolution
look at molecules such as cytochrome C (protein found in mitochondria used for respiration) something that we all have because we all respire. You can compare the sequence of amino acids so the smaller the number of differences in the cytochrome c proteins, the more closer they are related
Why do we look at biological evidence
because conversion evolution is misleading
Looking at dna
some sequences highly conserved so comparison. Similar sequence indicates recent common ancestor. This is the best way to check but it can be time consuming. If there are differences it may be due to mutations which is a sign of evolution.
3 domain classification
- Bacteria, archaea, eukaryotic
- Bacteria, archaea, eukaryotic closeness
archaea and the bacteria are quite different, archaea are closer to the eukaryotic