Classifciation and Evolution Flashcards
Taxonomy and the taxon groups (8)
- The science of classifying living things
- 7 Taxons; Kingdoms Phylum Class Order Family Genus Species
Biodiversity (4)
- The variation of organisms;
Genetically
Using Habitats
Species variation
What criteria is used when classifying in taxonomy (5)
- Anatomy and physiology
- Biochemistry
- Behaviour
- Genes
- Phylogeny; evolutionary relationships
Classification (2)
- Arrangement of organisms into various groups
- Based on their common features/ characteristics
Domains
- Largest taxa as it only contains three groups
- Eukarya; all the eukaryotes are grouped here- Animals, Plants, Fungi, Protoctist.
- Archaebacteria; closer related to eukaryotes
- Eubacteria
Describe the Plant kingdom (4)
- Eukaryotic
- Multicellular
- cellulose cell wall
- autotrophic
Describe the kingdom of animals (4)
- Multicellular
- heterotrophs
- fertilised eggs develop into blastula
- eukaryotes
Describe the kingdom of Fungi (6)
- Eukaryotic
- Multicellular
- Saprophytic
- contains mycelium
- chitin cell wall
- contains hyphae
- reproduces via spores
Why is classification used on organisms? (3)
- Clearly identifies species
- Predicts characteristics: if one member in a group has a trait, more likely others will too.
- Finds evolutionary links: characteristics are probably shared due to a common ancestor
Adaptations (4)
- characteristics that increases an organism’s chance of survival and reproduction in a specific environment
- Anatomical
- Behavioural
- Physiological
Examples of Anatomical adaptations (4)
- Body Coverings; hair, scales, shells, feathers
- camouflage; blend to the environment which allows hiding from predators
- teeth; shape of them is related to an organism’s diet
- Mimicry; copying appearance and sounds
Behavioural adaptations (4)
- innate or learned
- survival; eg playing dead
- Courtship; elaborate actions to attract mates
- seasonal; cope with changes in environment (hibernation and migration)
Physiological adaptations (3)
- Poison; eg venom
- Antibiotic production
- water holding; storage of water such as cactus and camel
Adaptations (4)
- characteristics that increases an organism’s chance of survival and reproduction in a specific environment
- Anatomical
- Behavioural
- Physiological
Examples of Anatomical adaptations (4)
- Body Coverings; hair, scales, shells, feathers
- camouflage; blend to the environment which allows hiding from predators
- teeth; shape of them is related to an organism’s diet
- Mimicry; copying appearance and sounds
Behavioural adaptations (4)
- innate or learned
- survival; eg playing dead
- Courtship; elaborate actions to attract mates
- seasonal; cope with changes in environment (hibernation and migration)
Physiological adaptations (3)
- Poison; eg venom
- Antibiotic production
- water holding; storage of water such as cactus and camel
Evidence for evolution (3)
- Palaeontology; fossils
- Comparative anatomy
- Comparative Biochemistry; genetic makeup
How is palaeontology useful as evidence for evolution? (4)
- Helps predict the age of organisms; older organisms are from deeper layers
- Evidence for simple life forms complex life; Simplier fossils like bacteria are in older rocks whereas complex ones are in newer rocks
- Ecological links; plants occurs before animals therefore animals needed plants to survive
- Anatomical similarities observed; eg skeleton
Reasons why the fossil record is incomplete? (3)
- Soft body tissue decomposes quickly so organisms that are mainly that will not be persevered
- conditions may have not allowed some fossils to form; eg volcanoes
- some just haven’t been found
How is comparative anatomy useful as evidence for evolution? (3)
- Differences and similarities with living species can be observed
- Homologous structures are evidence for divergent evolution
- Can show how organisms evolved from a common ancestor due to similar underlying structure; eg vertebrate limbs
What are homologous structures?
- Structures that are superficially different in organisms but have the same underlying structure
- eg pentadactyl limbs in vertebrates have the same arrangement of bone
Types of Variation (2)
- Interspecific
- intraspecific
Causes of variation (6)
- Genetic; inheriting alleles, mutations, sexual reproduction, chance and meiosis
- Environmental reasons
Ways of representing genetic variation
- Discontinuous; only certain discrete values- usually genetic
- Continuous; range of values from one extreme to another which usually forms a normal distribution curve
Characteristics of a distribution curve (3)
- Mean, median and mode are the same
- bell shape symmetry about the mean
- extreme values are very low whilst most values are close to the mean
Types of statistical test (3)
- Standard deviation
- Student’s t test
- PMCC
Analogous structures
Structures that perform the same roles but have a different genetic origin
Eg fish and whale fin
Convergent evolution (2)
- when unrelated species begin to share similar traits
- This is due to organisms adapting to similar environments or selection pressures
Selection pressure
Factors that affect the organism’s chances of survival or reproductive success
Describe natural selection (4)
- Variation; species show this in their characteristics usually due to genetic causes
- Survival; those better adapted to a selection pressure are more likely to survive and reproduce: eg competition, disease, predation
- Passing alleles; organisms that survive pass on advantageous characteristics to their offspring
- Overtime the gene pool population of the advantageous adaptation increases. Eventually evolution of a new species occur.
What is divergent evolution? (2)
- Different species with adaptive features evolve from a common ancestor
- closely related species diversified to adapt to a new habitat
How is comparative biochemistry evidence for evolution. (6)
- Differences and similarities in protein molecules
- Links with cytochrome C
- Ribosomal RNA have a slow rate of substitution
- Evolutionary embryology show animals in their earliest phase
- Sequence of DNA bases
- Sequences of amino acids
Why are the estimates for the number of species not accurate (4)
- Not all species have been discovered
- Some are difficult to distinguish
- some may have become extinct
- speciation occurs; new species being formed
What is the founders effect (3)
- When new colonies are formed geographically isolated from the original one as a result of a dying population
- founders now have different Genes; the one that survived selection pressure
- causes a smaller gene pool
Genetic bottleneck (2)
When a large number of organisms in a population dies before reproducing.
This leads to a reduction in genetic biodiversity as the surviving population are usually very genetically similar.
Genetic drift
- The frequency of occurrence of an allele vary due to the random nature of alleles being passed on
- This can cause the existence of a certain allele to disappear altogether
Horizontal transmission in bacteria
- When bacteria exchange alleles between different species, which can cause greater resistance amongst a wider population
Vertical transmission
- Bacteria containing resistant genes and passing them on via reproduction
