Classification and Evolution Flashcards
Define the term Classification
The act of arranging organisms into groups based on their similarities and differences
Define the term taxonomy
The study of classification
Define the term taxonomic group
The hierarchical groups of classification- domain, kingdom, phylum, class, order, family, genus, species
Define hierarchical
Arranged so that each entity is subordinate to a different entity.
Define phylogeny
The evolutionary relationships between organisms
List the seven taxonomic groups, in order, from the broadest to the smallest.
Domain, kingdom, phylum, class, order, family, genus, species
Name the taxonomic level that has been added above kingdom.
Domain
Give 3 reasons why scientists classify organisms.
- To identify species- by using defined system of classification, the species an organism belongs to can be easily identified.
- To predict characteristics- if several members in a group have a specific characteristic, it’s likely other species in the group will have the same characteristic
- To find evolutionary links- species in the same group probably share characteristics as they have evolved from a common ancestor
Define the term “species”.
The smallest and most specific taxanomic group. A species are a group of organisms that are able to reproduce and produce fertile offspring.
Explain why horses and donkeys are separate species, and why mules are not given a scientific name and are not a separate species.
When horses and donkeys breed they produce infertile offspring.
Mules are the offspring of a donkey and a horse. they are infertile because their cells contain an odd number of chromosomes. Because it’s infertile they are not classified as a species- so no scientific name
Define scientific name
The taxonomic name of an organism that consists of its genus and species
Define binomial nomenculture
The scientific naming of a species with a Latin name made of two parts- the first indicating the genus and the second the species
Define generic name
The first word in binomial nomenculture that indicates the an organism’s genus.
Define specific name
The second word in binomial nomenculture that indicates the organism’s species
Explain how scientific names of species are derived from the classification of a species and state the conventions used in writing them.
Write in italics or underline the name. It should be written in lower case except for the first letter of the genus name.
Name the 5 kingdoms and give examples of the organisms they contain.
- Prokaryotae (bacteria)
- Protoctista (the unicellular eukaryotes) Amoeba.
- Fungi (yeasts, moulds, mushroom)
- Plantae (the plants)
- Animalia (animals)
Describe the characteristics of Prokaryotae
- Unicellular
- No nucleus or other membrane bound organelles- a ring of naked DNA- small ribosomes
- No visible feeding mechanism- nutrients are absorbed through cell wall or produced internally by photosynthesis.
Describe the characteristics of Protocista
- Mainly unicellular
- A nucleus and other membrane-bound organelles
- Some have chloroplasts
- Some are sessile but others move by cilia or flagella or amoeboid mechanisms
- Nutrients are acquired by photosynthesis (autotrophic feeders), ingestion of other organisms (heterotrophic feeders) or both, some are parasitic
Describe the characteristics of Fungi
- Unicellular, multicellular
- A nucleus and other membrane-bound organelles and a cell wall mainly composed of chitin
- No chloroplasts or chlorophyll
- No mechanisms for locomotion
- Most have a body or mycelium made of threads or hyphae.
- Nutrients are acquired by absorption- mainly decaying material- they are saprophytic feeders- some are parasitic.
- Most store their food as glycogen
Describe the characteristics of Plantae
- Multicellular
- A nucleus and other membrane-bound organelles including chloroplasts, and a cell wall mainly composed of cellulose
- All contain chlorophyll
- Most do not move, although gametes of some plants move using cilia or flagella
- Nutrients are acquired by photosynthesis- they are autotrophic feeders- organisms that make their own food.
- Store food as starch
Describe the characteristics of Animalia
- Multicellular
- A nucleus and other membrane-bound organelles (no cell walls)
- No chloroplasts
- Move with the aid of cilia, flagella, or contractile proteins, sometimes in the form of muscular organs
- Nutrients are acquired by ingestion- they are heterotrophic feeders
- Food stored as glycogen
State the 3 domains of life and the 6 kingdoms in the ‘Three Domain system’- Woese’s system
- Domains- Bacteria, Archaea and eukarya
2. Kingdoms- Eubacteria, archae-bacteria, protoctista, plantae, fungi, animalia
Describe the characteristic features of Bacteria
- Have 70s ribosomes
2. RNA polymerase contains 5 proteins
Describe the characteristic features of Archaea
- Have 70s ribosomes
2. RNA polymerase of different organisms contain between eight and 10 proteins.
Describe the characteristic features of Eukarya
- Have 80s ribosomes
2. RNA polymerase contains 12 proteins
Describe the evidence used to create the “Three Domain System” of classification.
Scientists can discover evolutionary relationships between organisms by comparing DNA and protein structure.
These observations are used to classify organisms.
Define phylogeny
The study of living organisms based on their evolutionary relationships
Define phylogenetic tree
It is a diagram used to represent evolutionary relationships between organisms.
Shows common ancestors
Define the term sister group
Two descendants that split form the same node are called sister groups
Define node
The points where new lines branch off
Define tip
Tips on phylogenetic trees represent groups of descendant organisms.
Describe the advantages of using phylogenetic trees as a form of classification as opposed to just using taxonomic groupings.
- Uses phylogeny to confirm classification groups or caused them to be changed.
- Produces continuous tree whereas classification requires discrete taxonomical groups- scientists aren’t forced to put organisms into a specific group that they don’t quite fit.
- The hierarchical classification can be misleading as it implies different groups within the same rank are equivalent.
State 3 different sources of evidence for evolution
- Palaeontology- study of fossils and the fossil record
- Comparative anatomy- the study of similarities and differences between organism’s anatomy
- Comparative biochemistry- similarities and differences between the chemical makeup of organisms
Explain how the fossil record provides evidence for evolution.
- Fossils of simpler organisms are found in the oldest rocks, whilst fossils or more complex organisms are found in more recent rocks.
- Sequence in which organisms are found matches their ecological links with each other-plant fossils found before animal fossils.
- Study similarities in anatomy of fossil organisms- shows how closely related organisms have evolved from the same ancestor