A-Level Biology > 10 Classification > Flashcards

10 Classification Flashcards

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1
Q

What is classification?

A

Classification is the name given to the process by which living organisms are sorted into groups.

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2
Q

What are taxonomic groups?

A

The hierarchical groups of classification- domain, kingdom, phylum, class, order, family, genus, species

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3
Q

What are the seven groups?

A 
Kingdom
Phylum
Class
Order
Family
Genus 
Species
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4
Q

Whar is the biggest and broadest taxonomic group?

A

Kingdom

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5
Q

What is the smallest and most specific classification?

A

Species

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6
Q

Why do scientists classify organisms?

A

1) To identify species- by using a clearly defined system of classification, the species an organism belongs to can be easily identified.
2) To predict characteristics- if several members in a group have a specific characteristic, it is likely that another species in the group will have the same characteristic.
3) To find evolutionary links- species in the same group probably share characteristics because they have evolved from a common ancestor.
- By using a single classification system, scientists worldwide can share their research. Links between different organisms can be seen, even if they live on different continents.

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7
Q

What three domains can the classification system be separated into?

A

Archea, Bacteria, and Eukarya

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8
Q

What is binomial nomenclature?

A

The scientific naming of a species made of two parts- the first indicating the genus and the second the species.

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9
Q

What are the five kingdoms?

A

Living organisms can be classified into five kingdoms:

  • Prokaryotae (bacteria)
  • Protoctista (the unicellular eukaryotes)
  • Fungi (e.g yeasts, moulds and mushrooms)
  • Plantae (the plants)
  • Animalia
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10
Q

What are the general features of prokaryotae?

A
  • Unicellular
  • No nucleus or other membrane bound organelles- a ring of ‘naked’ DNA- small ribosomes
  • No visible feeding mechanism- nutrients are absorbed through the cell wall or produced internally by photosynthesis.
    Examples include the bacteria: Escherichia coli, staphylococcus aureus, and Bacillus anthracis
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11
Q

what are the general features of protoctista?

A
  • (Mainly) unicellular
  • A nucleus and other membrane bound organelles
  • Some have chloroplasts
  • Some are sessile, but others move by cilia, flagella, or by amoeboid mechanisms
  • Nutrients are acquired by photosynthesis, ingestion of other organisms, or both- some are parasitic.
    Examples include species belonging to the genera Paramecium and Amoeba.
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12
Q

What are the general features of Fungi?

A
  • Unicellular or multicellular
  • A nucleus and other membrane bound organelles and a cell wall mainly composed of chitin
  • No chloroplasts or chlorophyll
  • No mechanisms for locomotion
  • Most have a body or mycelium made of threads or hyphae
  • Nutrients are acquired by absorption- mainly from decaying material- they are saprophytic feeders- some are parasitic
  • Most store their food as glycogen
  • Examples include mushrooms, moulds and yeast.
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13
Q

What are the general features of animalia?

A
  • Multicellular
  • A nucleus and other membrane bound organelles (no cell walls)
  • No chloroplasts
    -Move with the aid of cilia, flagella, or contractile proteins sometimes in the form of muscular organs
  • Nutrients are acquired by ingestion, they are heterotrophic feeders
  • Food stored as glycogen.
    Examples include mammals such as cats, reptiles such as lizards, birds, insects, molluscs, worms, sponges, and anemones.
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14
Q

What are the general features of plantae?

A
  • Multicellular
  • A nucleus and other membrane bound organelles including chloroplasts, and a cell wall mainly composed to cellulose.
  • All contain chlorophyll
  • Most do not move, although gametes of some plants move using cilia or flagella
  • Nutrients are acquired by photosynthesis - they are autotrophic feeders- organisms that make their own food.
  • Store food as starch.
  • Examples include flowering plants such as roses, trees such as oak and grasses.
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15
Q

Three Domain System: Eukarya

A
  • Eukarya has 80s ribosomes.

- RNA polymerase contains 12 proteins.

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16
Q

Three domain system: Archaea

A
  • They have 70s ribosomes
  • RNA polymerase of different organisms contain between eight and ten proteins and is very similar to eukaryotic ribosome.
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17
Q

Three domain system: Bacteria

A
  • They have 70s ribosomes.

- RNA polymerase contains five proteins.

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18
Q

How many kingdoms does Woese’s system have and why?

A

Six.

  • This is because the prokaryotae kingdom becomes divided into two- Archebacteria and Eubacteria.
  • The six kingdoms are therefore: Archaebacteria, Eubacteria, Protoctista, Fungi, Plantae and Animalia.
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19
Q

Why are eubacteria classified in their own kingdom?

A
  • Eubacteria are classified in their own kingdom because their chemical makeup is different from Archaebacteria.
  • For example, they contain peptidoglycan in their cell wall whereas Archaebacteria do not.
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20
Q

What are archaebacteria?

A
  • Archaebacteria also known as ancient bacteria can live in extreme environments.
  • These include hot thermal vents, anaerobic conditions, and highly acidic environments.
  • For example, methanogens live in anaerobic environments such as sewage treatment plants and make methane.
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21
Q

What are eubacteria?

A
  • Eubacteria, also known as true bacteria, are found in all environments and the ones you are most familiar with.
  • Most bacteria are of the eubacteria kingdom.
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22
Q

What is phylogeny?

A
  • Phylogeny is the name given to the evolutionary relationships between organisms.
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23
Q

What is phylogenetics?

A
  • The study of the evolutionary history of groups of organisms.
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24
Q

What is phylogenetic tree?

A
  • A phylogenetic tree is a diagram used to represent the evolutionary relationships between organisms.
  • Phylogenetic trees are produced by looking at similarities and differences in species’ physical characteristics and genetic makeup.
  • The closer the branches, the closer the evolutionary relationship.
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25
What are the advantages of phylogenetic classification?
1) Phylogeny can be done without reference to Linnaean classification. Classification uses knowledge of phylogeny in order to confirm the classification groups are correct or causes them to be changed. 2) Phylogeny produces a continuous tree whereas classification requires discrete taxonomical groups.
26
What sources do scientists use to study the process of evolution?
1) Palaeontology-The study of fossils and fossil record. 2) Comparative anatomy- The study of similarities and differences between organisms anatomy. 3) Comparative biochemistry- Similarities and differences between the chemical makeup of organisms.
27
What evidence is provided by the fossil record?
1) Fossils of the simplest organisms such as bacteria and simple algae are found in the oldest rocks, whilst fossils of more complex organisms such as vertebrates are found in more recent rocks. This supports the evolutionary theory that simple life forms gradually evolved over an long period of time into more complex ones. 2) The sequence in which the organisms are found matches their ecological links to each other. E.g plant fossils appear before animal fossils. This is consistent with the fact that animals require plants to survive. 3) Fossils allow relationships between extinct and living organisms to be investigated.
28
What is the homologous structure and why does it prove divergent evolution?
Homologous structure is a structure that appears superficially different in different organisms, but has the same underlying structure. This proves that from a common ancestor, different species have evolved, each with a different set of adaptive features, which is what divergent evolution is.
29
What is divergent evolution?
Species diverge over time into two different species, resulting in a new species becoming less like the other
30
What is comparative biochemistry?
- Comparative biochemistry is the study of similarities and differences in the proteins and other molecules that control life processes. - To discover how closely two species are related, the molecular sequence of a particular molecule is compared. - Scientists do this by looking at the order of DNA bases, or at the order of amino acids in a protein. - Two of the most common molecules studied are cytochrome c, and ribosomal RNA. - Cytochrome C is a short protein found in many species. The more similar the amino acid sequence of cytochrome C in two different species, the more closely related the species are likely to be.
31
What are variations?
Variations are the differences in characteristics between organisms.
32
What is interspecific variation?
The differences between organisms of different species. E.g a bird has two legs, whereas a dog has 4 legs
33
What is intraspecific variation?
The differences between organisms of the same species. E.g people vary in height, hair colour etc.
34
Which two factors cause variation?
1) An organism's genetic material- differences in the genetic material an organism inherits from its parents leads to genetic variation. 2) The environment in which the organism lives- this causes environmental variation.
35
What is genetic variation?
A variety of different combinations of alleles in a population.
36
What are the genetic causes of variation?
1) Alleles- genes have different alleles. With a gene for a particular characteristic, different alleles produce different effects. E.g the gene for human blood groups has three different alleles (A, B and O) 2) Mutations- changes to the DNA sequence and therefore to genes can lead to changes in the proteins that are coded for. 3) Meiosis- Gametes are produced by the process of meiosis. Before the nucleus divides and chromatids of a chromosome seperate, the genetic material inherited from the two parents is 'mixed up' by independent assortment and crossing over, leading to the gametes of an individual showing variation. 4) Sexual reproduction- the offspring produced from two individuals inherits genes from each of the parents. Each individual produced therefore differs from the parents. 5) Chance- Many different gametes are produced from the parental genome. During sexual reproduction, it is a result of chance as to which two combine. The individuals produced therefore also differ from their siblings as each contains a unique combination of genetic material.
37
Examples of environmental causes of variation
- Plants with a greater access to the sun will generally grow larger than one in a shadier position. - Presence or absence of scars on your body occurs a result of an accident and have no genetic origin.
38
Examples of BOTH genetic and environmental causes
- Height- genes determine how tall an organism can grow. But diet or nutrient availability affect how tall an organism actually grows. - Your genes cause your skin colour, however when you expose your skin to sunlight, you produce more melanin to protect your skin from harmful UV rays hence you get darker.
39
What is continuous variation?
- A characteristic that can take any value within a range. - E.g the height and mass of plants and animals. - Not controlled by a single gene but a number of genes. - Also influenced by environmental factors.
40
What is discontinuous variation?
- A characteristic that can only result in certain values. - No in between values. - Determined purely by genetic factors. - E.g gender, blood groups - Controlled by a single gene.
41
What is a normal distribution curve?
- When continuous variation data are plotted onto a graph. | - Bell-shaped curve
42
What does standard deviation measure?
- It is a measure of how spread out the data is. | - The greater the standard deviation, the greater the spread of data.
43
What is spearman's rank correlation coefficient used for?
- This is used to consider the relationship between two sets of data.
44
What are adaptations?
Adaptations are characteristics that increase an organisms chance of survival and reproduction in its environment.
45
What three groups can adaptations be divided into?
1) Anatomical adaptations 2) Behavioural adaptations 3) Physiological adaptations
46
What is anatomical adaptations?
Physical features (internal and external)
47
What are behavioural adaptations?
The way an organism acts. These can be inherited or learnt from their parents.
48
What are physiological adaptions?
Processes that take place inside an organism.
49
What are some examples of anatomical adaptations?
- Body covering - Camouflage - Teeth: the shape and type of teeth present in an animals jaw are related to its diet. - Mimicry: copying another animals appearance or sound allows a harmless organism to fool predators into thinking it is poisonous and dangerous.
50
What is marram grass?
A xerophyte, a plant that has adapted to live in an environment with little water.
51
What are adaptations of marram grass?
- It’sadaptations reduce the rate of transpiration: - Curled leaves to minimise the surface area of moist tissue exposed to the air, and protect the leaves from the wind. - A thick waxy cuticle in the leaves and stems, reducing water loss through evaporation. - Stomata sunk into pits, which make them less likely to open and lose water. - Hairs on inside surface of leaves to trap moist air close to leaf, reducing diffusion gradient.
52
What are some behavioural adaptations?
- Survival behavioural: e.g an opossum plays dead and a rabbit freezes when they have been seen. - Courtship - Seasonal behaviours e.g migration, hibernation
53
What are the two main categories of behavioural adaptations?
1) Innate behaviour: the ability to do this is inherited through genes. E.g the behaviour of spiders to build webs 2) Learned behaviour- learnt from experience or from observing from other animals.
54
What are some examples of physiological adaptations?
1) Poison production: Many reptiles produce venom to kill their prey and many plants produce posions in their leaves to protect themselves from being eaten. 2) Antibiotic production- some bacteria produce antibiotics to kill other species of bacteria in the surrounding area.
55
What are analogous structures?
Structures that have adapted to perform the same function but have a different origin.
56
What is convergent evolution?
Organisms evolve similarities because the organisms adapt to similar environments or other selection processes.
57
What happens during natural selection?
1) Organisms within a species show variation in characteristics due to differences in genes. 2) Organisms whose characteristics are best adapted to a selection pressure e.g predation, competition have increased chance of surviving and reproducing. 3) Successful organisms pass the allele encoding the advantageous characteristic onto their offspring. 4) The process repeats for every generation and so over time, the proportion of individuals with the advantageous adaptation increases. 5) This process can lead to the evolution of species over a very long period of time.
58
What does selection pressure mean?
Factors that affect an organism's chance of survival or reproductive success.
59
What are some modern examples of evolution?
1) Antibiotic-resistant bacteria | 2) Peppered moths
60
How did bacteria become resistant to antibiotics?
- Bacteria reproduce very rapidly and evolve in a relatively short time leading to a higher chance of mutations occuring. - When the bacteria were exposed to the antibiotic, resistant individuals survived and reproduced, passing the allele for resistance on to their offspring. - Over time, the number of resistant individuals in the population increased.
61
Why did the population of dark peppered moths increase?
- During the industrial revolution many trees became darker due to being covered in soot. - Therefore, the dark moths were better adapted and more camouflaged. - More dark peppered moths survived and reproduced, increasing the frequency of dark moths in the population.
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