Module 4- classification Flashcards
What is the definition of a species?
A group of organisms that are able to reproduce to produce fertile offspring
What are the reasons for classification?
- convenience
- make study of living things more manageable
- make identification of organisms easier
- help us see the relationships between species
what is the modern classification hierarchy?
Domain
Kingdom
Phylum
Class
Order
Family
Genus
What happens as you descend to lower taxonomic groups?
becomes harder to separate closely related species
who created the binomial naming system?
Carl Linneaus. Genus and species name used, universal so aims to avoid confusion
what are the 5 kingdoms?
Plantae, prokaryota, animalia, protoctista and fungi
Characteristics of plantae kingdom
- eukaryotic
- multicellular
- cells surrounded by cellulose cell wall
- autotrophic
- contain chlorophyll
Characteristics of animalia kingdom
- eukaryotic
- multicellular
- heterotrophic- digest large molecules
- usually able to move around
characteristics of prokaryota kingdom
- no nucleus
- loop of DNA
- naked DNA
- no membrane bound organelles
- smaller ribosomes
-free living or parasitic
characteristics of protoctista
- eukaryotic
- mostly single celled
- wide variety of forms
- free living
- autotrophic
characteristics of fungi
- eukaryotic
- single celled
- walls made of chitin
- cytoplasm is multinucleate
- free livinf and sacrophytic
What are the 3 domains and who suggested this idea
Eukaryotae
Archaea
eubacteria
suggested by Carl Woese who divided the kingdom prokaryotae into two groups: eubacteria and archaea
What are archaea?
- extremophils
- live in extreme environments
- no nucleus
- no peptidogylcan cell walls
- unique lipids in membrane
- ribosomal structure more similar to eukaryotes
- DNA transcription similar to eukaryotes
what are eubacteria
no nucleus
vary in size
divide by binary fission
what evidence is used in classification?
biological molecules
DNA
Cytochrome C
how are biological molecules used in classification?
They help determine how closely related one species is to another species. Assuming that all living things all had identical versions of biological molecules, any changes are due to evolution. Therefore by comparing bio molecules two organisms with similar molecules are likely to be closely related.Difference between molecules show evolutionary relationships
how is Cytochrome C used as evidence in classification?
it is used in every cell that respires, however it is not identical in all organisms therefore the amino acids sequence in cytochrome c can be compared between organisms to draw conclusions about how closely related organisms are
How is dna used as evidence in classification?
comparison of dna sequences provides another way to classify species, if many differences the species have evolved seperately for a long time and so are less closely related. It is the most accurate way.
What are the two types of classification?
- artificial classification- based on a few characteristics, does not reflect evolutionary relationship. Groups things that are easy to remember
- natural classification- uses many characteristics, reflects evolutionary relationships, detailed study of individual species.
what is phylogeny?
Study of evolutionary relationships between species.
what does a phylogenic tree show?
shows how closely related species are. The closer together on the tree= more closely related. Branches represent when two species begin to evolve differently
describe darwins findings
Darwin and Wallace- galapagos islands and variation between same bird species found on different islands. shaped development of idea that offspring are genetically similar, no two individuals are identical and stable population size. Survival of the fittest
what evidence is there for evolution?
fossil evidence- comparison between living species and dead species, can then be used to understand evolution and changes through time.
biological molecules- evidence from molecules such as cytochrome c, idea that all species arose from one biological ancestor due to fact that organisms have the basic bio molecules and so changes show evolutionary differences, structure of DNA and dna sequencing can be compared to show similarities and differences between species
what is meant by variation?
difference that exists between two or more things/ individuals
what is intraspecific variation?
variation within species eg eye colour, hair colour
what is intraspecific variation?
variation between species
what is continuous variation?
two extremes and a full range of values between the extremes. most individuals are close to the mean eg height, length of leaves plotted on a histogram
what is discontinuous variation?
distinct categories and nothing in between eg human blood groups, gender, flower colour plotted on bar graph
what are two causes of variation and describe them?
genetic- variation caused by processing a different combination if alleles. genes that we inherit from our parents
environmental- variation caused by a response to environmental factors e.g tanned due to sunlight exposure
what is meant by combined effects?
idea that genetic and environmental factors are not isolated. Many characteristics are affected by both causes of variation eg tall because of a better diet and genetic influences
what is adaptation?
a characteristic that enhances survival in the habitat
what are the three different types of adaptation?
anatomical- structural adaptations such as long roots and extensive root network in marram grass
behavioural- ways behaviour has been modified for survival such as marram grass leaves roll when there is a shortage of water
physiological- affect the way that processes work such as leaves containing lignified cells that provide support when turgidity is lost
what is natural selection?
‘survival of the fittest’
an individual with a characteristic which helps them survive
how does natural selection work- describe the process
- mutation
- creates genetic variation
- environment selects- selection pressure
- individual with advantageous characteristic survives
- advantageous allele passed on
