4.3 Classification And Evolution Flashcards
Define binomial system
A system that uses the genus name and the species name to avoid confusion when naming organisms
Define classification
The process of placing living things into groups
Why do we classify organisms?
- For our convenience
- To make studying them more manageable
- To make it easier to identify organisms
- To help us see he relationships between species
Order of taxonomic levels
Domain Kingdom Phylum Class Order Family Genus Species
What are the three domains?
Archaea
Eubacteria
Eukaryotae
What are the five main kingdoms?
Plante Animalia Fungi Protoctista Prokaryotae
What is phylum?
Same BODY PLAN, e.g. backbone (vertebrates and invertebrates)
What is class?
Same general traits, e.g. number of legs
What is order?
Subdivision of class with additional information (e.g. carnivora + herbivora)
What is family?
A group of closely related genera
e.g. dogs and cats
What is genus?
A group of closely related species
What are Chordata?
- A phylum, nervous system with central bundle of nerves in back protected by vertebral column
- Vertebrates
What are anthropoda?
- Hard exoskeleton
- Invertebrates
Human taxonomic levels
Eukaryotae Animalia Chordata Mammalia Primate Hominidae Homo Sapiens
Why doesn’t using a common name work well?
- Different common name in different parts of country
- Different common names in different countries
- Translation gives different names
- Same name different species
What is the phylogenetic definition of a species
A group of individual organisms that are very similar in appearance, anatomy, physiology, biochemistry and genetics
Name a single celled organism that has chloroplasts
Euglena
Features of prokaryotae
No nucleus Loop of naked DNA No membrane bound organelles Small ribosomes Small cells Free living or parasitic
Features of protoctista
All eukaryotic Mostly single celled Plant or animal like features Mostly free living Autotrophic or heterotrophic nutrition
Features of fungi
Eukaryotic
Can be single cells (yeast) / mycelium or hyphae
Chitin walls
Multinucleate cytoplasm
Saprophytic (decay of organic matter) and free living
Features of plantae
Eukaryotic Multicellular Autotrophic Cellulose cell wall Chlorophyll
Features of animalia
Able to move around
Heterotrophic
Multicellular
Eukaryotic
Bacteria and archae difference
Different cell membrane structure
Different flagella
Different RNA enzymes
Diffferent mechanisms for DNA replication
Similarities between archae and eukaryotes
Similar enzymes for making RNA
Similar mechanisms for DNA replication
Anatomical adaptations of marram
Curled leaves Folded lower epidermis (create pits) Hairy lower epidermis (reduces air movement) Long roots (water deep underground) Low density of stomata (stabilise also) Spread roots Waxy cuticle
Physiological adaptations of marram
Roll leaves
Guard cells
Low water potential for salty conditions
Lignin - keep upright when water is not available
What is convergent evolution
Where two species evolve to look very similar due to similar lifestyles
Define adaptation
A characteristic that enhances survival in the habitat
Define anatomy
Structural features
Define behavioural adaptations
The ways behaviour is modified for survival
Define physiological adaptations
Affect the way that processes work
Define standard deviation
Measure of spread around a mean
What does a value of 1 mean for correlation coefficient
Perfect correlation
Define genetic variation
Variation caused by possessing a different combination of alleles
What is a mnemonic for the order of classification
Dumb Kids Playing Catch On Freeway Get Squashed
Difference between bacteria and archaea?
- cell membrane
- flagella
- RNA synth. enz.
- naked DNA (archaea have proteins associated with DNA)
- DNA replication mechanisms
Evidence that has lead to new classification systems, such as the three domains of life
- similarities in biological molecules
- genetic evidence
What is important to remember when writing out the binomial name of a species?
Underlining it
Define species
a group of organisms that can freely interbreed to produce fertile offspring
Problems in using observable characteristics in classification
convergent evolution makes organisms look similar
What is cytochrome c used for and what is it?
- protein
- used in respiration
How can cytochrome c be used in classification?
- different amino acid sequences
- more differences = less closely related species
What is monophyletic?
species described belong to the same phylogenetic group (same phylum)
Why is it difficult to define bacteria as a species?
Species = fertile offspring + genetic similarity
- divide by binary fission
- plasmids vary widely in DNA content and can be considered part of bacterial genome
Define natural selection
The term used to explain how features of the environment apply a selective force on the reproduction of individuals in a population
What four observations did Darwin make?
- offspring generally appear similar to their parents
- no two individuals are identical
- organisms have the ability to produce large numbers of offspring
- populations in nature tend to remain stable in size
What did Darwin conclude?
- there is a struggle to survive
- better adapted pass on characteristics
- changes make new species over time
Evidence for evolution
- fossils
- biological molecules (DNA and cytochrome c)
Steps of natural selection
- mutations = different versions of gene (alleles)
- intraspecific variation
- selective pressure favours advantageous characteristics
- survive and reproduce
- pass on characteristics
- next generation = higher proportion of those successful characteristics
What is continuous variation?
variation where there are two extremes and a full range of values between
What is discontinuous variation?
where there are distinct characteristics with nothing in between
What is environmental variation?
variation caused by response to environmental factors such as light intensity
What is genetic variation?
Variation caused by possessing a different combination of alleles
Examples of continuous variation
height
length of leaves on oak tree
length of stalk (reproductive hyphae)of a toadstool
number of flagella on bacterium
What is discontinuous variation regulated by?
- single gene
- not affected by environment
Examples of discontinuous variation
gender
some bacteria have flagella and others do not
human blood groups
Behavioural adaptation of marram
- rolling leaf more tightly
- closing stomata
- when covered in sand, will grow more quickly
What characteristics do marsupial moles and placental moles share?
- cylindrical body
- small eyes
- strong front legs
- large claws on front legs
- short fur
- short tail
- nose with tough skin for protection
