Unit 4.3- Classification and evolution Flashcards
Binomial system definition:
A system that uses the genus name and species name to avoid confusion when naming organisms
What is the order of the modern classification hierarchy
- Domain
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
What are the three domains of the classification hierarchy?
- Archaea
- Eubacteria
- Eukaryote
What are the five kingdoms of the classification hierarchy?
- Plantae
- Animalaia
- Fungi
- Protacista
- Prokaryote
How does does phylum category divide organisms?
Splits them into organisms that have the same body plan e.g. possession of a backbone
How does the class category divide organisms?
Splits organisms into groups that all posses the same general traits e.g. same number of legs
How does the order category divide organisms?
A sub division of class using additional information e.g. carnivores and herbivores
How does the family category divide organisms?
Closely related genera e.g. dog family
How does the genus category divide organisms?
A group of closely related species
How did Aristotle classify living things?
Into plants and animals. He furthered classified animals into those who:
- Live and move in water
- Live and move on land
- Move through the air
How did electron microscopes help with classification?
They revealed further details inside cells. Made it clear that many single celled organisms share some features of both plants and animals so do not fit into either kingdom
What are the features of prokaryotae?
- No nucleus
- Loop of DNA not arranged in linear chromosomes
- Naked DNA
- No membrane bound organelles (prokaryotic)
- Smaller ribosomes than other groups have
- Smaller cells than eukaryotes have
- May be free living or parasitic
What are the features of protacista?
- Eukaryotic
- Mostly single cells, but many algae are multi cellular
- Show a variety of form (only similarity is that they don’t fit into the other groups)
- Mostly free-living
- Have autotrophic or heterotrophic nutrition
What are the features of fungi?
- Eukaryotic
- Can exist as single cells, or they have a mycelium which consists of hyphae
- Have walls made of chitin
- Have a cytoplasm that is multinucleate (more than one nucleus per cell)
- Mostly free living and saprophytic (cause decay of organic matter)
What are the features of plantae?
- Eukaryotic
- Multicellular
- Have cells surrounded by a cellulose cells wall
- Autotrophic (absorb simple molecules and build them into larger organic molecules)
- Contain chlorophyll
What are the features of anamalia?
- Eukaryotic
- Multicellular
- Heterotrophic (digest large organic molecules into smaller molecules for absoption
- Usually able to move around
What evidence can be used in classification?
- Cytochrome C
- DNA
What is cytochrome C and how is it used for classification?
A protein used in respiration. All living organisms that respire have cytochrome C, but it is not identical in all species. The amino acids that make up cytochrome C can be identified and the more similar the two sequences from two different species are, the more closely related the species are
How is DNA used for classification?
Mutations are changes to the sequence of bases. The more similar a part of the DNA the more closely related two species are. If they are quite different, it suggests the species evolved separately a long time ago so are less closely related.
What did Carl Woese base his ideas for the three-domain classification system on?
the ribosomal RNA gene
What is the three domain classification system like?
- Prokaryotes are split into two groups: bacteria (eubacteria) and archaea (archaebacteria)
- Eukaryotes
Why in the three domain classification system are prokaryotes split into two groups?
Bacteria are fundamentally different from Archaea and eukaryotes
What are the differences between bacteria and archaea and eukaryotes?
Bacteria have:
- A different cell membrane structure
- Flagella with a different internal structure
- Different enzymes
- No proteins bound to their genetic material
- Different mechanisms for DNA replication and for synthesising RNA
What features do archaea share with eukaryotes?
- Similar enzymes for synthesising RNA
- Similar mechanisms for DNA replication and synthesising RNA
- Production of some proteins that bind to their DNA
Phylogeny definition:
The study of the evolutionary relationships between organisms
What is artificial classification?
Classification for convenience
- Based on only a few characteristics
- Does not reflect any evolutionary relationships
- Provides limited information
- Is stable
What is natural classification?
- Uses many characteristics
- Reflects evolutionary relationships
- Provides a lot of useful information
- May change with advancing knowledge
Natural selection definition:
The term used to explain how features of the environment apply a selective force on the reproduction of individuals in a population
What are the observations Darwin made?
- Offspring generally appear similar to their parents
- No two individuals are identical
- Organisms have the ability to produce a large number of offspring
- Populations in nature tend to remain fairly stable in size
What are the conclusions Darwin made from his observations?
- There is a struggle to survive
- Better-adapted individuals survive and pass on their characteristics
- Over time, a number of changes may give rise to a new species
What evidence is there for evolution?
- Fossil evidence
- Biological molecules
Why is mitochondrial DNA useful for tracking human ancestry?
- It does not get confused with the paternal DNA
- There is lots of variation in mDNA from different parts of the world, which allows the movement of people to be traced
Continuous variation definition:
Variation where there are two extremes and a full range of values in between
Discontinuous variation definition:
Where there are distinct categories and noting in between
Environmental variation definition:
Variation caused by response to environmental factors such as light intensity
Genetic variation definition:
Variation caused by possessing a different combination of alleles
Interspecific variation definition:
The differences between species
Intraspecific variation definition:
Variation between different members of the same species
Adaptation definition:
A characteristic that enhances survival in the habitat
Anatomical adaptations definition:
Structural features enhancing survival chances
Behavioural adaptations definition:
The way that behaviour is modified for survival
Physiological adaptations definition:
Affect the way processes work e.g. a black bear’s heart beat dropping while hibernating
What is a well adapted organism able to do?
- Find enough food or photosynthesise well
- Find enough water
- Gather enough nutrients
- Defend itself from predators and diseases
- Survive the conditions of its environment
- Respond to changes in its environment
- Have sufficient energy to allow successful reproduction
What are the anatomical adaptations of marram grass?
- Long roots that spread over a wide area and deep underground
- Leaves are curled, building up moisture inside and reducing evaporation
- Lower epidermis covered in hairs, reducing air movement
- Few stomata
- Waxy cuticle
What are the behavioural adaptation of marram grass?
- Responds to a shortage of water by rolling the leaf more tightly and closing the stomata
- When covered by grass, marram grass will grow more quickly to reach the sunlight
What are the physiological adaptations of marram grass?
- The ability to roll its leaf is due to the action of specialised hinge cells in the lower epidermis
- The guard cells open and close the stomata
- Maintains a low water potential lower than other plants, which enables it to live in salty conditions by the sea
- Leaves contain many lignified cells that provide support when turgidity is lost, keeping the leaf upright when water is not available