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AS Biology (Unit 2: F212) > Classification > Flashcards

Flashcards in Classification Deck (23)
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1
Q

What is biological classification?

A

The process of sorting living things into groups, either by natural (evolutionary) relationships or artificial (physical) relationships.

2
Q

What is taxonomy?

A

The study of differences between different species. These can be physical, anatomical or physiological. Species that have many physical similarities are usually grouped together, making taxonomy the study of principles behind classification.

3
Q

What is natural classification?

A

Grouping similar individuals into species and grouping species in terms of how closely related they are, usually reflecting their evolutionary history.

4
Q

What is phylogeny?

A

The study of how closely related species are to each other in terms of their evolutionary history. Species that share a more recent common ancestor are thought to be more related to each other.

5
Q

What are the 5 kingdoms?

A
  1. Prokaryota.
  2. Protoctista.
  3. Fungi.
  4. Plantae.
  5. Animalia.
6
Q

What are the features of prokaryotes?

A
  • Include bacteria and cyanobacteria.
  • Have no membrane bound nucleus, only circular ring of DNA called nucleotid.
  • Have no membrane bound organelles.
    Have cell walls made from peptidoglycan.
  • Use autotrophic or heterotrophic nutrition.
  • Have 70s ribosomes instead of 80s.
  • Single-celled and smaller than eukaryotes.
  • Can be free-living or parasitic.
  • Can have flagella for mobility.
7
Q

What are the features of protoctista?

A
  • Include organisms like paramecium and plasmodium.
  • Are eukaryotes, so cells have membrane bound nucleus containing genetic information.
  • Have membrane bound organelles.
  • Display variety of plant-like/animal-like features.
  • Use autotrophic and heterotrophic nutrition (photosynthesis, saprophytic nutrition…).
  • Usually single-celled organisms.
  • Do not fit into any of the other 4 kingdoms.
  • Can ave undulipodia for mobility.
8
Q

What are the features of fungi?

A
  • Include yeast and slime moulds.
  • Are eukaryotic, so have membrane bound nuclei, but cytoplasm not divided into individual cells, and are multinucleate.
  • Have membrane bound organelles.
  • Have cell walls made from chitin.
  • Use saprophytic nutrition (secretion of extracellular enzymes and absorption of digested products).
  • Are usually multicellular and arranged into mycelium containing hyphae.
  • Are not mobile
9
Q

What are the feature of plants?

A
  • Include oak trees and cacti.
  • Are eukaryotes, so cells have membrane bound nucleus.
  • Have membrane bound organelles.
  • Have cell walls made from cellulose.
  • Develop multicellular embryos during reproduction.
  • Use autotrophic nutrition (Photosynthesis).
  • Are multicellular.
  • Are not mobile.
10
Q

What are the features of animals?

A
  • Include humans and crocodiles.
  • Are eukaryotic, so cells have membrane bound nucleus.
  • No cell walls, only plasma membrane.
  • Develop multicellular embryos during reproduction.
  • Use heterotrophic nutrition (digest and absorb organic matter).
  • Are multicellular.
  • Have muscles for mobility.
11
Q

Why do we classify living things?

A
  • Convenience.
  • To make studying them easier.
  • To make identifying them easier.
  • To help us see how different species are related to each other.
12
Q

What is the traditional method for classifying living things?

A

Putting them into groups based on physical similarities and differences.

13
Q

What are the eight taxonomical groups?

A
Domain.
Kingdom.
Phylum.
Class.
Order.
Family.
Genus.
Species.
14
Q

What is the relationship between different taxonomical groups?

A

As you go from species to domain, the members of different groups become more different from each other. For example, 2 members of different species in the same genus are more similar to each other compared to 2 members from different genera.

15
Q

How are species put into different groups?

A

Different species are put into different taxonomical groups in order. For example, they are put into a kingdom and then into phylum within that kingdom etc. It is easier to separate species into the higher taxonomical groups as they are very different from each other. However, as you go down the classification system, it becomes increasingly more difficult as the groups become more similar from each other.

16
Q

What is an example of classification?

A
Domain: Eukaryotae.
Kingdom: Animalia.
Phylum: Chrodata.
Class: Mammalia.
Order: Primate.
Family: Hominidae.
Genus: Homo.
Species: Sapiens.
(Humans)
17
Q

What is the binomial nomenclature for naming organisms?

A

Universal scientific name for different species, consisting of 2 latin names to identify each species; the genus and the species name.

18
Q

Why are common names not used to identify species?

A
  1. Same species may have different common names in different parts of the same country.
  2. Different common names used for same species in different countries.
  3. Translation into different languages may give different meanings.
  4. Same common name could be used to identify different species in different areas.
19
Q

Why is it important to identify different species?

A

We need to be able to identify the presence of different species within a habitat in order to know about its biodiversity, especially if there are endangered species within a habitat.

20
Q

What modern techniques are available to aid classification?

A

Some biological molecules, especially proteins and DNA, are present in all living things but may differ from species to species. Their similarities between species may help us determine how closely related species are.

  • An example is cytochrome c which is vital in respiration for most living things. The primary structure of cytochrome c can be analysed and compared between species to determine how closely related they are.
  • DNA coding for the same genes can also be sequenced for different species and compared. The more similar they are, the more related the species are.
21
Q

What is the 3 domain classification system?

A

Domain is a taxonomical group above kingdom and splits living things into 3 separate domains: Eukaryotae, bacteria and archaea.

22
Q

What are the similarities between 3 domains and 5 kingdoms classification?

A
  • Eukaryotes still remain separate from prokaryotes.

- Beyond kingdoms, species still remain in the same taxonomical groups as before.

23
Q

What are the differences between 3 domains and 5 kingdoms classification?

A
  • 5 kingdom classification is based on physical relationships between species whereas 3 domains is based on phylogenetic relationships.
  • Prokaryotes are in one group with the 5 kingdom classification whereas they’re in 2 for 3 domain classification.
  • 3 domains tells us how closely related species in each domain are in terms of evolutionary history whereas 5 kingdoms does not.