4.3 Classification and Evolution

  • Created by: elbungay1
  • Created on: 09-06-19 12:13
Why do we classify organisms?
Convenience, makes studying of organisms more manageable, makes it easier to identify living organisms, hels identify relationships between species
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What is the modern classification hierarchy?
Domain, Kingdom, Phylem, Class, Order, Family, Genus, Species
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What is a Domain?
Highest taxonomic rank. Three domains Archaea, Eubacteria and Eukaryotae
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What is a Kingdom?
5 Main Kingdoms: Plantae, Animalia, Fungi, Protoctista (all eukaryotes, possess a nucleus) and all single cell organisms without a nucleus are in kingdom Prokaryotae.
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Describe feautures of organisms in Prokaryotae kingdom
Have no nuclues, have a naked loop od DNA, not wrapped around histone proteins into linear chromosomes, have no membrane bound organelles, smaller ribosomes than eukaryotes, smaller cells than eukaryotes, may be free-living or parasitic
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Describe features of organisms in Protoctista kingdom
Eukaryotic, mostly single celled, have wide variety of forms, show various plant or animal like features, don't fit into other kingdoms, heter or autotrophic, free living
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Describe features of organisms in Fungi kindgom
Eukaryotic, single celled or have mycelium consisting of hyphae, walls made of chitin, cytoplasm is multinucleate, mostly free-living and saprophytic - cause decay of dead matter
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Describe features of organisms in Plantae kingdom
Eukaryotic, multicellular, cells surrounded by cellulose cell wall, autotrophic (Absorb simple molecules and build them into larger organic molecules), contain chlorophyll
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Describe features of organisms in Animalia kingdom
Eukaryotic, multicellular, heterotrophic (digest large organic molecules to form smaller ones for absorption, usually able to move around
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What is convergent evolution?
When two unrelated speices adapt to their environment in similar ways so that they look similar
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What is Cytochrome c?
Protein uses in respiration. All respiring organisms have it but is not identical in all species. Using amino acid sequence of two different species, the more differences found, the less closely related they are. Closely related species have the same
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How is DNA used in classification?
Changes in DNA occur at random - mutations. Comparing DNA from two species, the greater the number of differences, the longer the species have evolved independently.
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How is Eubacteria different from kingdoms Archaea and Eukaryotae?
Bacteria have different cell membrane structure, flagella with a different internal structure, different enzymes (RNA Polymerase) for synthesising RNA, no proteins bound to genetic material, different mechanisms for DNA replication and making RNA
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How is the Kingdom Archaea similar to Eukaryotae
Similar enzymes (RNA Polymerase) for synthesising RNA, simialr mechanisms for maing RNA and DNA replication, production of some proteins that bind to their DNA
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What is artificial classification?
Classifications for convenience e.g. book with all yellow flowers on one page. Bases on only a few characteristics, doesn't reflect evolutionary relationships, provides limited information but is stable
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What is natural classification?
Organisms are classified using the modern hierarchy. Uses many characteristics, reflects evolutionary relationships, provides a lot of information, may change with advancing knowledge.
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What is Phylogeny?
Study of evolutionary relationships between organisms. The more closely related organisms are, the closer the common ancestor.
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What does monophyletic mean?
Organisms that have evolved from the same common ancestor
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What 4 Observations did Darwin make to theorise Natural Selection
Offspring generally appear similar to their parents, no two individuals are identical, organisms have the ablity to produce a large amount of offspring, populations in nature tend to remain fairly stable in size
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What is Darwins conclusions of Natural Selection?
There is a struggle to survive, better-adapted individuals survive and pass on their characteristics, in time, a number of changes may give rise to a new species
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What fossil evidence is there for evolution?
In the past, world was inhabited by species that were different from those today, old species have died and new species have arisen, the new species that have appeared are often similar to the older ones found in the same place.
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What Biological Molecule evidence is there for evolution?
Species have given rise to another, both likely to have simialr biological molecules, cytochrome c, species took separate evolutionary paths a long time ago, biological molecules likely to differ more
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What is variation?
Presence of variety, the difference between individuals
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What is interspecific variation?
Differences between species
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What is intraspecific variation
Differences between individuals of the same species
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What is continuous variation?
Two extremes and a full range of intermediate values between the two extremes. Most individuals are close to mean value. Polygenic, regulated by more than one gene, can be influenced by environment. Height in humans, length of leaves
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What is discontinuous variation?
Two or more distinct categories with no intermediate values. Members may be evenly spread or more of one type than other. Regulated by one gene, not influenced by environment. gender, blood type, flagella or not in bacteria
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What are the causes of Variation?
Inherited/genetic-combination of alleles inherited is not the same as any other living thing, combination of alleles is unique. Environmental-skin tan, soil avaliability leading to height of plant. Both-height due to diet, puberty switches on genes
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What is the correlation coefficient?
Measure of how closely two sets of data are correlated. Value of 1 means perfect correlation
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What is standard deviation?
A measure of the spread around a mean
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What is the student's t-test
a test to compare two means
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What is an adaptation?
A characteristic that enhances survival in a habitat
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What will a well-adapted organism be able to do?
Find enough food or photosynthesise well, find enough water, gather enough nutrients, defend from predators and diseas, survival abiotic features of environment, respond to changes in environment, sufficient energy for reproduction
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What is Marram Grass?
Highly adapted plant, adapted to living on sand dunes with little water available. Xerophyte and needs to take up as much water as possible and lose as little as possible
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What are the anatomical adaptations of Marram Grass
Long and spread out roots- find as much water as possible. Curled leaves, lowers SA exposed to light. Lower epidermis have hairs and folded pits, reduces water vapour potential gradient. Low density of stomata, thick waxy cuticle
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What are the behavioural adaptations of Marram Grass
Has to respond to changes in environment. Responds to shortage of water by rolling leaf more tightly and closing stomata to reduce transpiration.
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What are the physoiological adaptations of marram grass
Ability to roll leaf due to action of specialised hinge cells, guard cells can open and close stomata, maintains lower cell water potential than other plants, allowing it to survive sea spray. Leaves lignified to maintain support when tugidity is los
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Describe adaptations of Moles
Convergent evolution of marsupial moles and european. Cylindrical body, small eyes, strong front legs, large claws on front legs, short tail, short fur, tough nose skin for protection
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Describe the process of natural selection
mutation creates alternate versions of gene (alleles), creates intraspecific variation, there is selection pressure, advantageous characteritics allow survival, inheritance, change in allele frequency, higher proportion of advantageous allele.
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What examples of evolution are present today?
Pesticide resistance in insects and antibiotic resistance in bacteria
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Other cards in this set

Card 2


What is the modern classification hierarchy?


Domain, Kingdom, Phylem, Class, Order, Family, Genus, Species

Card 3


What is a Domain?


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Card 4


What is a Kingdom?


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Card 5


Describe feautures of organisms in Prokaryotae kingdom


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