4.2.2- Classification and Evolution Flashcards
what is classification?
the process of identifying and putting species into groups.
why is classification used?
- to organise knowledge of life
- to avoid confusion
- to help study evolutionary relationships
what is used as the practise of biological classification?
the taxonomic hierarchy
what is the order of the taxonomic hierarchy?
- domain
- kingdom
- phylum
- class
- order
- family
- genus
- species
how are organism grouped into the taxonomic hierarchy?
used to organise and group similar organisms together so that they are easier to understand
how do you work out the binomial name of a species?
genus name + species name.
what is the name of taxonamy?
the science involved with classifying groups, based on shared characteristics.
why do biologists classify organisms?
- species identification (identifying members of species based on shared characteristics)
- predict characteristics (looking at shared group characteristics to predict the characteristics of species as a whole)
- evolutionary links (members of same species will have similar characteristics that can be traced to a common ancestor.
why are binomials useful for scientists?
they allow for species to be universally identified
-the binomial for a species is the same across the entire glob
what is binomial?
the scientific name for a species?
what are the 5 kingdoms?
- prokaryotae (bacteria)
- protoctista (unicellular eukaryotes)
- funghi
- plantae (plants)
- animalia (animals)
what are key features of prokaryotae?
- unicellular
- no nucleus, ring of ‘naked’ DNA + ribosomes
- no membrane-bound organelles
- no visible feeding mechanism, nutrients absorbed through cell wall/produced through photosynthesis.
what are 3 examples of prokaryotae?
- escherichia coli
- staphylococcus aureus
- bacillus anthracis
what the key features of protoctista?
- mainly unicellular
- nucleus + membrane bound organelles
- no cellulose cell wall
- some have chloroplasts
- sissile (don’t move), while others move by cilia, etc
- autotrophic feeders, nutrients from photosynthesis
- heterotrophic feeders, or parasitic= both
what are 2 examples of protoctista?
- amoeba
- paramecium
what are the key features fungi?
- unicellular/multicellular
- nucleus + membrane-bound organelles
- chitin cell wall
- no chloroplasts/chlorophyll
- body/mycelium of threads/hyphae
- saprophytic feeders, nutrients from absorption
- store food as glycogen
what are 2 examples of fungi?
- mushrooms
- yeast
what are the key features of plantae?
- multicellular
- nucleus + membrane-bound organelles, chloroplasts
- cellulose cell wall
- chlorophyll
- do not move= sessile
- autotrophic, nutrients from photosynthesis
- store food as starch
what are 2 examples of plantae?
- trees
- grasses
what are the key features of animalia?
- multicellular
- nucleus + membrane-bound organlles, no cell wall
- motile, move with aid of cilia, flagella, contractile proteins
- heterotrophic, nutrients from ingestion
- food stored as glycogen
what are 2 examples of animalia?
- mammals (eg-cats)
- reptiles (eg-snakes)
what has lead to classification changing/new classification systems?
- development of tech
- increased knowledge of genetics/biological molecules
- scientists now use observable features, genetics and evolutionary relationships to classify
what did the 5 kingdoms develop into?
3 domains + 6 kingdoms
what are the 3 domains?
- archaea
- bacteria
- eukarya
what are the key features of eukarya?
- organised chromosomes, proteins around nucleus
- RNA polymerase contains 12 proteins
- 80s ribosomes
what are the key features of bacteria?
- 1 chromosome
- 70s ribosomes
- RNA polymerase contains 5 proteins
what are the key features of archaea?
- 1 chromosome
- 70s ribosomes
- RNA polymerase contains between 8-10 proteins
what is a phylogenetic tree?
a diagram that depicts lines of evolutionary descent from a common ancestor.
what is phylogeny?
the evolutionary relationships between organisms, revealing what group a particular organism is related to, and how closely related they are
how are phylogenetic trees produced?
by looking at the similarities/differences in species’ physical characteristics and genetic makeup.
what are the 2 advantages to phylogenetics?
- confirms if classification groups are correct, or what caused them to change.
- produced a continuous tree
what are the differences between phylogeny and classification?
- P= continuous tree. C= taxonomical groups
- C= can be misleading as it implies that different groups within the same rank are equivalent.
what is the definition of evolution?
the way in which species have changed/evolved over time, through natural selection
who were the two scientists who contributed to the theory of evolution?
- Darwin
- Wallace
what were the observations created by Darwin?
- all organisms produce more offspring than could ever actually survive
- populations of organisms do fluctuate (change over time) but not significantly.
- populations of the same species of organisms show variation in characteristics between individuals
- offspring inherit characteristics from their parents
what are the 3 pieces of evidence for evolution?
1- palaeontological (fossils)
2-comparative anatomy
3- comparative biochemistry
describe palaeontological (fossil evidence)?
- provided through fossil record
- oldest rocks contain fossils of simplest organisms, recent rocks contain fossils of more complex organisms
- this supports idea that simple life evolved over time into more complex ones
- plant fossils appear before animal fossils, supports, as animals require plants to survive
- similarities in anatomy of fossilised organisms/current organisms show that they have evolved from same ancestor
- allows links between existing/extinct species to be investigated.
describe comparative anatomy?
- studies similarities/differences in existing species
- uses homologous structures to compare between species
- features on surface look different, but underneath have same structure
- homologous structures suggest that each species has evolved from a common ancestor, but has gained different adaptations dependent on their habitat (divergent evolution)
describe comparative biochemistry?
- studies similarities/differences in proteins/other molecules that control life processes
- some important molecules are conserved amongst species, the same/have small differences across unrelated species
- studied= cytochrome c (for respiration) + ribosomal RNA
- identify when changes occur and the evolutionary links associated with the changes.
what are the two types of variation?
- intraspecific
- interspecific
what is variation?
the differences that exist between two or more organisms
what is interspecific variation?
the variation between species
what is intraspecific variation?
the variation within a species
what is discontinuous variation?
a characteristic within a species that can only result in certain values,cannot be measured over a range
eg-bacterial shapes
what is continuous variation?
a characteristic within a species that can take any value within a range, controlled by multiple genes
how is discontinuous variation shown?
- qualitative differences in phenotype
- distinct categories exist
- represented by bar charts
how is continuous variation shown?
- quantitative differences in phenotypes
- no distinct classes/categories exist
- collated on frequency tables and plotted on histogram, with a distribution curve
- normal distribution= bell-shaped
what are the two causes of variation?
- genetic factors
- environmental factors
describe the environmental causes of variation?
-global environments have different conditions (eg- sunlight, availability of water, etc)
-factors affect how organisms grow/develop
-variation caused by the environment cannot be inherited by offspring
-example= eating too much with little exercise= weight gain
-
describe the genetic causes of variation?
- different genes have different effects on phenotype, plus different alleles have a large effect on the phenotype
- diploid organisms= inherit 2 alleles of each gene, either the same or different
- example of dv= attached ear/unattached ear
- different alleles have a small effect on phenotype, add together to have additive effect
what is a student’s T-test?
a test used to compare means of data values of two populations
what are the 3 adaptations of organisms to the environment?
- anatomical (physical features)
- physiological (processes inside)
- behavioural (way organism acts)
describe anatomical adaptations?
-development of body structures that enhance the survival of organism in the environment it lives in.
what is an example of anatomical adaptations?
different structures of beaks in birds due to the type of food eaten
describe physiological adaptations?
-ensures the correct functioning of biochemical/physiological processes in the organism in order for it to survive in it’s environment
what is an example of physiological adaptations?
camels have long loops of Henle in kidneys to conserve more water
describe behavioural adaptations?
- helps organism to survive in it’s environment
- happens more quickly than other adaptations, more intelligent an animal, faster it learns to make behavioural changes in order to survive
what is an example of a behavioural adaptation?
a possum will play dead in order to escape from a predator attack
what is an adaptation?
any variation/characteristic that helps an organism to survive and reproduce in the environment it lives in.
what can organisms that are well adapted to lived area do?
- survive/reproduce successfully
- pass on adaptations to offspring
- defend themselves from predators/disease
- survive physical conditions + fluctuations in environment
- respond to changes in the environment
- produce offspring that are more likely to survive to reproduce.
what are the 5 steps involved in the process of natural selection?
1- competition for survival 2-variation by random mutations in DNA 3- survival of the fittest 4- inheritance of beneficial allele 5-environmental change
what are selection pressures
factors that affect the organisms chance of survival/reproductive success
-those best adapted to their environment are most likely to survive
the best adapted species pass down what to their offspring?
the advantageous allele/characteristic
what are the 5 steps that follow natural selection?
1-organisms show genetic variation and show characteristic variation
2-these organisms have a better chance at survival, survival of the fittest
3-successful organisms pass on the advantageous characteristics to their offspring
4-process repeated, so the proportion of advantageous characteristics increases, frequency of allele increases in gene pool
5- evolution of new species
what is an example of an insect evolving to be resistant to pesticide?
sheep blowflies, who lay their eggs in faecal matter around a sheep’s tail, which hatch and cause sores
explain the evolution of the sheep blowflies?
- 1950s= diazinon pesticide used to kill flies, prevented condition occurring
- pre-adaptation to another chemical used in pesticides developed into pesticide resistance quickly, being passed on to their offspring
explain anti-biotic bacteria/drug resistance?
- MRSA
- mutation in some S. aureus occurred when bacteria replicated, which provided resistance to methicillin
- when bacteria was exposed to antibiotic, the resistant individuals survived and reproduced, which passed the allele to the offspring
- number of resistant over time increased
