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Biology need to knows⚠️ > Classification & Biodiversity > Flashcards

Classification & Biodiversity Flashcards

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1
Q

what is the phylogentic method?

A
  • A method used to group closely related organisms together
  • Organisms in the same group have a more recent common ancestor with each other than with organisms not in their group
  • If they are closely related they will show physical similarities
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2
Q

What happens the further up the diagram you go?

What do branch point represent?

A
  • the further forward in time

- Common ancestors

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3
Q

Define hierarchy

A

A system in which smaller groups are components of larger groups

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4
Q

What is a taxon?

A
  • Each grouping in the system is a taxon
  • Bigger taxa contain smaller taxa
  • Within each taxon, organisms are more similar to each other, and more closely related, than to organisms outside the taxon
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5
Q

What is the hierarchy of biological classification?

A

Domain>Kingdom>Phylum>

Class>Order>Family>Genus>Species

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6
Q

Moving down the hierarchy, from domain to species, organisms in a taxon are…

Moving up a hierarchy, from species to domain, members of a taxon are…

A

more closely related

less closely related

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7
Q

Classifying is part of human psychology, but there are other reasons for classifying living organisms: Pt 1

A
  • A phylogentic classification allows us infer evolutionary relationships. If two organisms are so similar that we put them in the same taxon, we infer that they are closely related
  • If a new animal is discovered we can predicts some of its other characteristics based on our understanding of similar organisms
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8
Q

Classifying is part of human psychology, but there are other reasons for classifying living organisms: Pt 2

A
  • When we communicate, it is quicker to say ‘bird, than ‘the vertebrate egg-laying biped with beak and feathers’
  • When describing the health of an ecosystem or the rate of extinction in the geological record, conservationists often find it more useful to count families than species
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9
Q

Why is our classification system described as ‘tentative,?

A
  • Our system fro classification depends on our current knowledge
  • Any system we use is tentative and may altered as our knowledge advances
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10
Q

What is a domain?

A

The largest taxon and all living things belong in 1 of the 3 domains. Domains were originally defined on the basis rRNA base sequence. More modern methods of analysis also consider similarities in the DNA base sequence

a) Eubacteria: These are the familiar bacteria such as E.coli and Salmonella
b) Archea: These are bacteria, and often have unusual metabolism; for example some generate methane . They live in marginal habitats and are all also prokaryotes
c) Eukaryota: Plantea, Animalia,Fungi and Protoctista

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11
Q

what does the 5 kingdom system classify organisms based on?

A

Their physical appearance

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12
Q

There are 5 kingdoms. Organisms in different kingdoms have major significant differences. Describe these 5 kingdoms

A
  • All bacteria, the Eubacteria and Archaea, are in one kingdom, the prokaryota.
  • The other 4 kingdoms contain eukaryote organisms
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13
Q

What is a phylum?

A

A phylum is a subgroup of a kingdom

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14
Q

Members of each phylum have distinct body plan. Give examples

A
  • Members of the phylum Annelida are soft bodied and segmented; members of the Arthropoda have chitinous exoskeleton and jointed limbs
  • The phylum chordata contains the vertebrates
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15
Q

What is a class?

A

A sub-group of a phylum e.g. Mammalia from a class within the phylum chordata; insecta are a class within the phylum Arthropoda

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16
Q

This is a sub-group of a class; e.g Lepidoptera

A

Order

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17
Q

Define a family?

A

A family is a group within an order

-Flower families are the most familiar, such as the rpse family, Rosacease

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18
Q

Define genus

A

A group of similar organisms such as the genus Panthera, containing lions and tigers

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19
Q

What genus do lions and tigers belong to?

A

Panthera

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20
Q

Define species

A

A group of organisms sharing a large number of physical features and able to interbreed to produce fertile offspring

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21
Q

Give two examples of species that cannot interbreed to produce fertile offspring

A
  • Camelus bactrianus & Camelus dromedarius

- Panthera leo & Panterea tigris

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22
Q

5 Kingdoms: Prokaryota

A
  • Porkaryota are microscopic

- This kingdom contains all the bacteria and the cynobacteria

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23
Q

5 Kingdoms: Protoctista

A
  • Some have only one cell and these are the major component of plankton
  • Others are colonial
  • Some have plant-like cells
  • Some have animal- like cells
  • Some have characteristics of both plant and animal like cells
  • Some have many similar cells e.g seaweeds or algae
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24
Q

5 Kingdoms: Plantae (Plants)

A
  • Mosses, horsestails and ferns reproduce with spores

- Conifers and flowering plants, which reproduce with seeds

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25
Q

5 Kingdoms: Fungi

A
  • Yeasts are single celled

- Mould such as penicillium and mushrooms

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26
Q

5 Kingdoms: Animalia (Animals)

A
  • The 35 animal phyla include a great range of body plans

- Most are motile at some stages of their life

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27
Q

What does the theory of evolution suggest?

A

That widely separated groups of organisms share a common ancestor
- therefore it would be expected that they share basic features, so their similarities should indicate how closely related they are

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28
Q

The more similar the two organisms are…

Groups with little in common…

A

The more recently they are assumed to have diverged

Presumably diverged from a common ancestor much earlier

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29
Q

What to look for when deciding how closely related two organisms are?

A

A biologist looks for homologous structures

- they may have different functions, but have a similar form and developmental origin

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30
Q

What is a good example to us when looking at how closely related organisms are and why?

A

The Pentadactyl limb of the vertebrate
- it’s basic structure is the same in all four classes of terrestrial vertebrates, amphibians, reptiles, birds and mammals

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31
Q

What functions have have different vertebrates adapted to have?

Give some specific examples of organisms

A

Grasping, walking, swimming, and flying

Examples include the human arm, the wing of a bat, the flipper of a whale, the wing of a bird and the leg of a horse

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32
Q

What is divergent evolution?

A

Where a common ancestral structure has evolved and performs different functions

33
Q

Why might some animals looks similar but may not be closely related?

A

Because their ancestors adapted to a similar environment so they evolved certain features that perform the same function

34
Q

some animals looks similar but may not be closely related. What is this an example of?

A

Convergent evolution

- in which structures evolve similar properties but have different developmental origins.

35
Q

structures evolve similar properties but have different developmental origins. What is this called?

A

Analogous

36
Q

Assessing relatedness with genetic evidence: DNA sequences

A
  • During the course of evolution, species undergo changes in their DNA Base sequences, which accumulate until the organisms are so different that they are considered to be different species
  • More closely related species shoe more similarity in their DNA base sequences than those more distantly related
  • DNA analysis has confirmed evolutionary relationships, and corrected mistakes made in classification based on physical characteristics
37
Q

Assessing relatedness with genetic evidence: DNA hybridisation

A
  • Involves comparing the DNA base sequences of two species
  • To work out how closely related two species of primates are e.g. Humans and the chimpanzee, Pan troglodytes, DNA from both is extracted, separated and cut into fragments
  • The fragments from the two species are mixed and, where they have complementary base sequences, they hybridise together
38
Q

Assessing relatedness with genetic evidence: Amino acid sequences

A
  • The sequences of amino acids in proteins is determined by the DNA base sequence
  • The degree of similarity in the amino acid sequence of the same protein in two species will reflect how closely related they are
  • Part of the fibrinogen molecule of various mammal species has been compared and differences in the amino acid sequences have allowed scientists to propose an evolutionary tree for mammals
39
Q

Assessing relatedness with genetic evidence: Immunology

A
  • The proteins of different species can be compared using immunological techniques
  • If you mix the antigens of one species, such as the blood protein albumin with specific antibodies of another, the antigens and antibodies make a precipitate
  • the closer the evolutionary relationship, the more the antigen and antibody react and make more precipitate
40
Q

The species concept: The morphological definition

A
  • if two organisms look very similar they are likely to be in the same species
  • there may be differences, such as the presence of a mane on male lions but not females
  • this ‘sexual dimorphism’ must be taken into account when deciding if organisms are the same species
41
Q

The species concept: The reproductive definition

A
  • another way of defining species states that two organisms are in the same species if they can interbreed to make fertile offspring
  • Dissimilar organisms may have a different number of chromosomes or incompatible physiology or biochemistry, so a hybrid would not be viable
42
Q

What is taxonomy?

What does this area of study allow us to do?

A

•Taxonomy is the identification and naming of organism
This area of study allows us to:
-discover and describe biological diversity
- investigate evolutionary relationships between organisms
- Classify organisms to reflect their evolutionary relationships

43
Q

The binomial system has 3 great advantages:

A
  • Unambiguous naming
  • Based on Latin, the scholarly language, so could be used all over the world
  • Implies that two species sharing part of their name are closely related
44
Q

How to use the binomial system:

A
  1. Each organism has two names, its genus and its species
  2. The genus name is the first word and has a capital letter
  3. The species name comes second and does not have a capital letter
  4. The first time the scientific name is used in a text, it is written in full, e.g. Panthera tigris
  5. If used again, the genus name be abbreviated, e.g. P.tigris
  6. Both names are printed in italics, or underlined when handwritten
45
Q

Define biodiversity

A
  1. The number of species, sometimes called ‘species richness’
  2. The number of organisms within each species
46
Q

Assessing relatedness with genetic evidence: DNA sequences

A
  • During the course of evolution, species undergo changes in the DNA base sequences, which accumulate until the organisms are so different that they are considered to be different species
  • More closely related species show more similarity in their DNA base sequences than those more distantly related
47
Q

How is assessing relatedness with DNA sequences useful?

A
  • Can be used to correct mistakes made in classification based on physical characteristics
48
Q

Assessing relatedness with genetic evidence:DNA hybridisation

A
  • Involves comparing the DNA base sequence of two species
  • To work out how closely related two organisms are;
  • DNA from both is extracted, separated and cut into fragments
  • The fragments from the two species are mixed and where they have complementary base sequences, they hybridise together
49
Q

Assessing relatedness with genetic evidence: Amino acid sequences

A
  • The sequences of amino acids in proteins is determined by the DNA base sequence
  • The degree of similarity in the amino acid sequence of the same protein in two species will reflect how closely related they are
  • e.g using Cytochrome c
  • The amino acid sequences have allowed scientists to propose evolutionary relationships
50
Q

Assessing relatedness with genetic evidence: Immunology

A
  • The proteins of different species can be compared using immunological techniques
  • If you mix the antigens of one species, such as blood protein albumin, with specific antibodies of another, the antigens and antibodies make a precipitate
  • The more the antigen and antibody react and make more precipitate
51
Q

Example of immunology

A
  1. Human serum injected into rabbit
  2. Rabbit serum containing anti-human antibodies
  3. Rabbit serum added to serum of other species
  4. Different amount of precipitation showing different evolutionary relationships
52
Q

The morphological definition:

A

If two organisms look very similar they are likely to be in the same species

53
Q

What is sexual dimorphism and why does it make it more difficult to classify organisms of the same species?

A
  • Sexual dimorphism is when males and females of the same species look different
  • e.g male lions have manes and female lions dont
  • This must be taken into account when deciding if two organisms are the same species
54
Q

The species concept: The reproductive definition

A
  • Another way of defining a species states that two organisms are in the same species if they can interbreed to make fertile offspring
  • Dissimilar organisms may have a different number of chromosomes or incompatible physiology or biochemistry, so a hybrid would not be viable
55
Q

What is taxonomy?

What does this area of study allowed us to do?

A

the identification and naming of organisms

  • Discover and describe biological diversity
  • Investigate evolutionary relationships between organisms
  • Classify organisms to reflect their evolutionary relationships
56
Q

The binomial system (gives organisms two names) has 3 great advantages

A
  1. Unambiguous naming
  2. Based on Latin, the scholarly language, so could be used all over the world
  3. Implies two species sharing part of their name are closely related e.g Panthera lion & Panthera tigris
57
Q

How do you use the binomial system?

A
  1. Each organism has two names, its genus and its species
  2. The genus name is the first word and a capital letter
  3. The species name comes second and does not have a capital letter
  4. The first time the scientific name is used in a text, it is written in full e.g Panthera tigris
  5. If used again, the genus name may be abbreviated e.g P.tigris
  6. Both names are printed in italics, or underlined when hand written
58
Q

Define biodiversity

A
  1. The number of species, sometimes called ‘species richness’
  2. The number of organisms within each species
59
Q

Examples of how biodiversity can vary spatially

A
  • More plants grow at high light intensity than at low light intensity, so a bright environment can support more more herbivores therefore more carnivores than a dull one
  • More energy flowing through an ecosystem produces more species and more individuals. This means that equatorial regions have a much higher biodiversity than polar regions
60
Q

2 examples of places with low biodiversity

2 examples of places with high biodiversity

A

Antarctica & (Sahara) desert

(New Zealand) rain forest & (Indonesian) Coral reef

61
Q

What are the 3 main reasons biodiversity can increase or decrease

A
  1. Succession: over time, a community of organisms changes its habitat, making it more suitable for other species
    The change in composition of a community over time is called ‘succession’ It increases animal biodiversity but ultimately decreases plant biodiversity
  2. Natural selection: this can generate and change biodiversity
  3. Human influence: in many areas of the world, human activity has made environment less hospitable to living organisms
    It has decreased their biodiversity and, in many cases, led to extinction
62
Q

Describe the ways in which human influence can alter biodiversity

A
  • in the tropical rain forests of Brazil and Costa Rica, farming, roads and industry have destroyed habitats and reduced the numbers of individuals and driven to extinction many species found nowhere else in the world
  • in oceans, over-fishing has depleted fish stocks and some very productive, diverse areas, such as coral reefs and estuaries, are severely stressed. Trawlers dredging the ocean floor disrupt habitats, damaging populations of invertebrates, fish and sea mammals
  • Misuse of land, such as trampling by cattle, accompanied by the increased temperature related to climate change, has increased the area of deserts. The Sahara Desert has expanded and large areas of Australia and North America are vulnerable
  • rivers are polluted with industrial chemicals. The Yangtze River dolphin, also called the baiji, was declared extinct in 2006. Its problems were made even worse by capture and by collisions with river traffic
63
Q

What is the significance of reduced biodiversity?

A

Many different plants and animals are used to support human civilisation:

  • A small number of plant species provide the dapple foods e.g wheat and rice
  • Medicinal drugs are derived from plants and fungi
  • Living organisms provide important raw materials e.g rubber,cotton
64
Q

What can a biodiversity index be used to do?

Give an example of a biodiversity index

A

A biodiversity index can be used to monitor the biodiversity of a habitat over time and to compare the biodiversity in different habitats
- An example is the Simpsons index

65
Q

What is the equation for Simpsons diversity index?

A

D = Σn(n - 1)

N(N - 1)

66
Q

Assessment of biodiversity with polymorphic loci

A
  • An examination of gene and alleles gives an assessment of biodiversity at the genetic level
  • this approach focuses on all the alleles present in the gene pool of the population, not on individuals
67
Q

What is a locus?

A

A genes position on a chromosome

68
Q

How does a locus show polymorphism?

A
  • If it has two or more alleles at frequencies greater than would occur by mutation alone
  • If a gene has more alleles, its locus is more polymorphic than if there were fewer
69
Q

DNA fingerprinting

A
  • organisms that are more closely related to each other have DNA base sequences that are more similar
70
Q

The DNA of organisms does not all code for protein

A
  • Like all DNA, non-coding sequences undergo mutation so individuals acquire different base sequences
71
Q

Sometimes it is only one base that differs

A
  • these single base differences are called SNPs, pronounced snips, which stands for single nucleotide polymorphisms
72
Q

What are hyper variable regions?

A
  • there are also regions of DNA that vary, generally about 20-40 base sequences long, often repeated many times
  • These unique lengths of non-coding DNA are called hyper variable regions (HVR) or tandem repeats
73
Q

How does DNA fingerprinting work?

A
  • Comparing the numb r and position in the DNA profiles of a population indicates how similar or different their DNA sequences are
  • The more of different SNPs and HVRs a population has, the more differences there are in its DNA fingerprints
  • More differences indicate a greater biodiversity. In a biodiversity population, DNA fingerprints show a lot of variation
74
Q

Describe the process of natural selection

A
  • As a habitat undergoes change, for example getting warmer, over many generations, individuals with alleles that are more suited to warmth will reproduce more efficiently until many of the population have those features
  • But the environment may change again, perhaps getting wetter
  • Now different features are more useful and they will be selected, so again, over many generations, the make-up model of the population changes
  • thus natural selection generates biodiversity
75
Q

How might natural selection decrease biodiversity?

A
  • This may happen when a selective insecticide kills all the aphids in a habitat, or when an asteroid crashes into the earth throwing dust into the atmosphere reducing light intensity so much that the plants cannot survive
  • then herbivores die so the carnivores die
  • in that situation, as happened with the dinosaurs, natural selection decreases the biodiversity and species may become extinct
76
Q

What is an adaptation?

A
  • The change in a species, as a useful characteristic becomes more common, is called ‘adaptation’
  • The useful characteristic is referred to as an ‘adaptive trait’
77
Q

Give examples of anatomical traits

A
  • Sharks, dolphins and penguins have streamlined bodies. Without this body shape, they would be less efficient at catching food or escaping predators
  • Some plants have flowers with their honey or nectar guides, sometimes called beelines. They indicate the centre of the flower, the source of nectar and pollen for visiting insects. A flower without these lines would attract fewer pollinators
78
Q

Give examples of physiological traits

A
  • Mammals and birds are endothermic and must avoid wasting energy trying to maintain body temperature in the cold.During hibernation, a polar bear resists its body thermostat to use less energy, and the body temperature drops to 2 degrees, rather than staying at 37 degrees
  • The leaves fall off deciduous plants when the temperature and light intensity decrease in autumn. This way, they do not lose water by transpiration and risk dehydration throughout the winter when water may be frozen, and so they survive the cold weather
79
Q

Give examples of behavioural traits

A
  • Like many plants, Crataegus laevigata, the hawthorn, flowers in spring when its pollinating insects have emerged. If it flowered earlier, it would not be pollinated
  • Mating rituals in animals include the displaying of a peacocks tail or elaborate dances performed by birds such as flamingos
  • They increase an animals chance of reproducing

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