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Diversity - Classification


In the response to population selection, what is being selected and what is necessary for survival?

phenotype is being selected

an organism that "works" in its environment

 

What advantage does the binomial system have over common names for plants?

  • It gives us an international standard name which is unique to a species of organism.
  • Common names may only be understood in one country or region and may refer to different plants in different places.

What do we mean by genus?

  • a group of more or less similar but not identical plants
  • includes more than one species

What is a species (defined by appearance, breeding group, physiology, habitat)?

a group of essentially similar looking plants which can breed with one another and probably live in the same kind of habitat

What further categories are there above the genus and below the species level?

  • above family, order, class, division, kingdom
  • below subspecies, cultivars, ecotypes, hybrids

What are the six kingdoms?

  • Archaebacteria
  • Eubacteria
  • Protista (I & II)
  • Fungi
  • Animalia
  • Plantae

Which of these are eukaryotes, which are prokaryotes and which are typically multicellular?

  • Archae- and Eubacteria are prokaryotes, the rest are eukaryotes
  • All eukaryotes except Protista I are usually organized multicellular organisms; others may form chains or clumps of cells but are not organized or differentiated

How did chloroplasts and mitochondria arise?

from eubacteria which were captured by an ancestral Archaebacterium

What kinds of organisms are viruses and lichens?

A virus is a piece of RNA or DNA in a protein coat (obligate parasites).

 

Lichens are formed by symbiotic association between cyanobacteria or green algae and fungi.

What features should members of the same species have in common:

  1. same flower color
  2. same number of leaves
  3. capacity to interbreed

  1. Flower color can be quite misleading; redbud trees with white flowers are still called Cercis canadensis or redbud.

     

  2. Unlike animals in which number of legs or other parts is fixed, plants can have variable numbers of appendages.

     

  3. Yes, capacity to mate (and produce viable offspring) is an important requirement of members of the same species.

What feature of plants is most reliable in the classification into families and genera

  1. flower structure
  2. geographical origin
  3. leaf shape

  1. Yes, this is generally the least variable aspect of plant structure and therefore the most reliable in discerning affinities.

     

  2. Genera can often be confined to particular areas, but families often occur over very wide areas.

     

  3. Leaves are highly variable structures, so related plants can look very different on casual observation, or plants in different families can have similar leaves.

What, apart from their autotrophic habit, distinguishes photosynthetic organisms (plants, algae, cyanobacteria) from animals

  1. lack of movement
  2. cell structure
  3. no single feature

 

There are mobile photosynthetic bacteria and algae.

 

Cell structures differ among bacteria, plants and algae; animals share features with other eukaryotic organisms.

 

At least some members of each of the plant-like groups has some feature in common with animals. There are even animals and animal-like protists that have captured chloroplasts so that they are capable of photosynthesis.

Which of the following are plants?

  1. liverwort
  2. fungus
  3. seaweed

  1. Liverworts do not look like most other plants, but they are the most primitive members of the plant kingdom according to current classification.

     

  2. Fungi are accepted as plants by most people, but they are non-photosynthetic and have chitin for cell walls.

     

  3. Seaweeds are accepted as plants by most people, but they have different cell wall structure, often different photosynthetic pigments and lack differentiated cells.

If the diploid number of chromosomes is 24 how many chromosomes are present in the zygote?

  1. 24
  2. 12
  3. 48

  1. Yes the zygote is the first diploid cell in the life cycle so it must have the diploid chromosome number.

     

  2. The zygote is the first cell from which a diploid organism develops after fusion of gametes.

     

  3. Most organisms do not exceed the diploid chromosome number during their life cycle.

If the zygote contains 24 chromosomes, how many would be in a gamete?

  1. 24
  2. 12
  3. 48

  1. Two gametes fuse to form a zygote.

     

  2. Yes two gametes (haploid or 1n) fuse to form a zygote (diploid or 2n)

     

  3. Two gametes fuse to form a zygote.

Transcription is the process whereby the code in messenger RNA is:

  1. converted to DNA
  2. read from DNA
  3. converted to protein

  1. Conversion from RNA to DNA is "reverse transcription", an exceptional process that only occurs in the reproduction of certain viruses.

     

  2. Yes transcription is the first stage of information processing from DNA through RNA to protein.

     

  3. Conversion from RNA to protein is "translation", the second stage of the information processing that is common to all organisms.

If GGU is the codon for glycine what base sequence would you expect on the transfer RNA for glycine?

  1. CCA
  2. GGU
  3. TTC

  1. Yes C pairs with G and A with U (or T in DNA)

     

  2. Bases pair with their complementary bases, not with the same base.

     

  3. T is not present in RNA (it is replaced by U which pairs with A).

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