M4 - Chapter 10 - Classification and Evolution Flashcards
Classification definition
The process by which living organisms are sorted into groups. They all share similar features.
What is the Taxonomic Group
The groups by which animals can be classified
Taxonomic Group
Kingdom Phylum Class Order Family Genus Species
Brief History of classification
Aristotle made a book about all the animals - 350 BC
Conrad Gesner produced another book about animals -1551
Carl Linnaeus produced another 10th edition of Systema Naturae, which was considered to be the starting of the binomial nomenclature - 1758
Ernest Haeckel proposed the 3rd Kingdom - 1866
A 5- kingdom classification system is proposed by Robert Whittaker- 1969
Carl Woese introduces a 6- Kingdom model - 1977
Why should we classify organisms
to identify species
to predict characteristics
(if several organisms in a group have a specific characteristic, then others included are likely to have it too)
To find evolutionary links (common ancestors)
Advantages of classifiying animals
Scientists all across the world can share their research and communicate using the Binomial Nomenclature names.
Species definition
A group of organisms that are able to produce fertile offspring.
What are the 3 domains
Archae
Bacteria
Eukarya
What is a common name
Names given according to a certain physical characteristic
What is wrong with using a common name
Scientists working internationally might have different names
It doesn’t provide any information about relationships
Binomial Nomenclature
- Genus
- Species
When typing, this name should be in italics or when written, it should be underlined
What are the 5 Kingdoms
Prokaryotae Protoctista (unicellular eukaryotes) Fungi Plantae Animalia
Features of Prokaryotae
- Unicellular
- No membrane-bound organelles
- Small ribosomes
- No visible feeding mechanisms (nutrients absorbed)
Features of Protoctista
- Mainly unicellular
- A nucleus and membrane-bound organelles
- Some have chloroplasts
- Some are sessile (immobile), but some can move by cilia/ flagella
- Nutrients gained by photosynthesis (autotrophic) or ingestion of organisms (heterotrophic feeders)
Features of Fungi
- unicellular or multi-cellular
- Membrane-bound organelles
- Cell wall made of chitin
- No chloroplasts/ chlorophyll
- No mechanism for movement
- Body or mycelium (vegetative part of a fungus)
- Nutrients are absorbed
- Saprophytic feeders (energy from decaying material)
- Some are parasitic
- Most store their energy as glycogen
Features of Plantae
- Multicellular
- Nucleus and other membrane- bound organelles
- cell wall made of cellulose
- All contain chlorophyll
- Most don’t move, but they can using cilia/ flagella
- Autotrophic feeders
- Store food as starch
Features of Animalia
- Multicellular
- No cell walls or chloroplasts
- Nucleus and membrane-bound organelles
- Move with cilia or flagella
- Nutrients gained by ingestion
- Food stored as glycogen
What was the original classification
Based on observable features
Three domain system general info
This is the current classification used today that was proposed by Carl Woese in 1997.
This system groups organisms using differences in the sequences in nucleotides in the cells’ ribosomal RNA and the cells’ membrane lipid structure and their sensitivity to antibiotics.
Three domain system Structure
3 domains then 6 kingdoms
Domains: Bacteria –> Eubacteria
Archae –>Archaebacteria
Eukarya –> The rest of the kingdoms
The Prokaryotes are basically replaced by Eubacteria and Archaebacteria
Eukarya
80s ribosomes
RNA polymerase (responsible for mRNA transcription)
contains 12 proteins
Archae
70s ribosomes
RNA polymerase contains 8-10 proteins
Bacteria (domain)
70s ribosomes
RNA polymerase contains 5 proteins
Archaebacteria
Live in extreme environments such as hot air vents or anaerobic.
Eubacteria
Normal conditions
Difference between Archaebacteria and Eubacteria
They have different chemical makeup. For example, peptidoglycan is in Eubacteria, but not in Archaebacteria.
What is phylogeny
the EVOLUTIONARY relationships between organisms
What is the link between phylogeny and classification
Phylogeny is used to classify organisms, and the closer the evolutionary relationships between organisms, the closer the taxonomic groups.
Advantages of phylogeny
Phylogeny produces a continuous tree, whereas classification requires discrete taxonomical group.
The hierarchy in classification can make it seem as if 2 groups are equal, however this may not always be correct. and can be quite misleading.
Evidence for evolution
- Palaeontology
- Comparative Anatomy
- Comparative Biochemistry
- Fossil Record
- Embryology
Palaeontology
Fossils are created and as the sediment builds up over time, and different layers of rocks are formed, scientists have noticed that the fossils at the bottom (which are older) are different to the ones at the top (which are younger). This is often called the Fossil Record
How are fossils made
Animals’ and plants’ remains that are preserved in rocks over years.
Evidence from the F.R
- Simpler organisms, such as bacteria are at the bottom, whereas more complex ones are at the top.
- The sequence that the organisms are found in matches their ecological links, like how plants were older than animals.
- By studying similarities (etc.) in the anatomy, you can figure out which ones are closely related.
- Fossils also allow relationships between extinct and extant organisms to be investigated.