classification and biodiveristy Flashcards
1
Q
what is biological classification said to be and what’s it function
A
- Biological classification is said to be phylogenetic:
- it reflects the evolution of
an organism, by placing organisms into groups according to visible external
features.
2
Q
what does a phylogenetic tree show
A
how organisms are related by showing their common ancestors
3
Q
domains
A
contain organisms that share a distinctive unique pattern of ribosmal RNA which establishes their close evolutionary relationship
4
Q
what sorting system does classification use
A
- Classification uses a hierarchy whereby smaller groups are placed into larger
ones, with no overlaps between the groups, called taxa. - One example is:
domain, kingdom, phylum, class, order, family, genus, species.
5
Q
what are the three domains
A
- There are three domains:
- Archaea (bacteria living in hostile environments,
e.g. extreme temperature, pH, salinity or pressure, with an unusual
metabolism, e.g. producing methane), - Eubacteria (common bacteria)
- Eukarya (the eukaryotes – includes plants, animals, fungi and protoctists).
This is the highest category into which organisms are classified.
6
Q
what are the five kingdoms
A
- plantae (plants)
- animalia (animals)
- fungi
- prokaryotes (bacteria)
- protoctists
7
Q
what are protoctists
A
- mainly unicellular eukaryotic microrganisms that do not form tissues
- many are photosynthetic eg algae
8
Q
what are kingdoms sorted into and why
A
- The kingdoms are then sorted into a large number of smaller groups called
phyla. - All members of a given phylum or division have certain things in common, e.g. the chordates all have a spinal cord.
9
Q
what is a sub group of phylum
A
- Each class that is a sub-group of a phylum, e.g. mammals are a class within
chordates, is subdivided into orders, e.g. humans belongs to the order of
primates.
10
Q
wat is the subdiviision of an order
A
family
11
Q
what are families divided into
A
- genera
- (singular genus)
12
Q
what is a genus
A
A genus is a group
of organisms with a large number of similarities but members of different
species within a genus are usually unable to interbreed successfully, e.g.
the horse and the donkey can produce offspring in the form of the mule,
but the mule itself is sterile.
13
Q
what are genera / genus sorted into
A
- Finally genera are subdivided into species – a category that consists of
a group of similar individuals that can interbreed and produce fertile
offspring. - They have a very large number of anatomical and physiological
similarities.
14
Q
species
A
consists of a group of individuals with similar
characteristics that can interbreed and produce fertile offspring.
15
Q
autotrophic nutrition
A
is making complex organic
molecules from simple inorganic ones using either light or chemical energy.
16
Q
heterotrophic nutrition
A
involves consumption of
already made complex
organic molecules.
17
Q
saprophytic nutrition
A
involves feeding on dead or decaying matter by the production of enzymes extracellularly and the subsequent absorption of
the products.
18
Q
parasitic nutrition
A
involves obtaining nutrients from a host organism over a long period of time, causing
it harm in the process.
19
Q
what is he binomial systen
A
- every organism has two names
- first name uses is the name of the genus to which the organism belongs - initial capital letter
- second name used is the name of the species to which the organism belongs possessed by only one kind of organism - has a small initial letter
20
Q
why is the binomial system used
A
- universal helps avoid confusion between different languages
21
Q
what does classifying organisms allow
A
By classifying organisms we can infer evolutionary relationships, and it makes
it easier to manage the large number of organisms.
22
Q
why is classification tentative
A
- based on our current knowledge
- may be subject to change as new species are discovered which do not fit
neatly into the groups currently available.
23
Q
what are key features of plantae
A
- are multicellular eukaryotic organisms that photsynthesise (autotrophic)
- reproduce using spores (eg mosses and ferns) or seeds (eg flowering plants and conifers)
- possess cellulose cell walls
24
Q
what are key features of animalia
A
- multicellular
- heterotrophic
- eukaryotic organisms
- lack cell walls
- show nervous cooridination
25
what are the key features of fungi
* Are multicellular (e.g. moulds) or single celled (e.g. yeast),
* eukaryotic organisms.
* In moulds, the body consists of a network of threads called hyphae.
* Cell wall is made of chitin.
* They are heterotrophic being either saprophytic or parasitic.
* Reproduce by production of spores (moulds) or by budding
(e.g. yeast).
26
what are key features of prokaryotes
* Microscopic, unicellular organisms including bacteria and cyanobacteria (blue-green algae).
* Cell wall is made of peptidoglycan (murein).
* Lacks membrane-bound organelles, and a true nucleus.
* Ribosomes are smaller than eukaryotes (70S).
27
what are the key features of protoctista
* Includes algae and slime moulds.
* Some are unicellular and resemble animal cells (e.g. Amoeba)
whilst others are colonial and have plant like-cells (e.g. Spirogyra).
* Contain membrane-bound organelles and a nucleus.
28
how can relatedness be assessed
* Determining the relatedness of species was initially performed by looking
at physical characteristics from living organisms and fossil evidence.
* The use of immunology and more recently DNA profiling has led to a greater
understanding of how closely related organisms are.
29
what is an exaple of a homologou structure
* An example in vertebrates is the pentadactyl limb (which means
having five digits). Its basic structure is similar in amphibians, reptiles, birds
and mammals, though they have very different functions in each.
30
what evolution are homologoes structures formed from
This shows evidence of divergent evolution where a structure has evolved from a
common ancestor to perform a different function.
31
homologous structures
structures in different species with a
similar anatomical position and developmental origin, derived from a common ancestor.
32
analogous structures
have a corresponding function and similar
shape, but have a different developmental origin.
33
what evolution is from analogous structures
Where structures are analogous, i.e. they have the same function but a very
different shape/structure; this provides evidence for convergent evolution
whereby ancestors have adapted themselves to the same environmental
pressure but from different developmental origins.
34
what is an example of analogous structures
An example is found
with the wings of a bird and those of a butterfly: both provide flight, but
due to their very different structures, there is no evidence that they shared a
common ancestor and so wings should not be used to classify them.
35
what is the main immunological technique used to show relatedness of species
the immunological comparison of proteins, and involves creating antibodies to one species’ protein in a rabbit, which can then be presented to other species’ proteins.
36
describe how using immunology you would compare living primates with a human to find it's closest ancestor
ancestor, a protein that is present in all
species would first need to be identified. The human protein is then injected into a rabbit to produce antibodies to it. This antibody serum is then added to protein from the other primates, e.g. chimpanzee, gibbon, and gorilla, and the degree of precipitation measured. If human antibody is added to the human protein, an exact antibody-antigen match occurs and there will
be 100% precipitation. As the similarity between the proteins diminishes, a lower degree of precipitation will be observed.This has been done with
haemoglobin, and the closest relatives were found to be the chimpanzee andgorilla both with 95% precipitation. When comparing the actual amino acid
sequence of haemoglobin from gorillas and chimpanzees with humans, the closest match was with the chimpanzee.
37
describe how DNA fingerprinting and sequence help to assess relatedness
As species evolve, changes occur in their DNA base sequences, so more closely related organisms show fewer differences in their base sequences. Comparing genetic (DNA) fingerprints and DNA sequences of genes has confirmed evolutionary relationships,
38
what is genetic fingerprinting based of in eukaryotes
the majority of the DNA does not code for polypeptides: these
non-coding regions between genes contain short DNA sequences that repeat, e.g. TATATATATATATATA, and are called satellites or STRs (short tandem repeats). The number of times that these repeat is unique and so forms the
basis of genetic fingerprinting.
39
biodiversity
the number of species and the number of individuals of each species in a specified geographic
region.
40
what is species richness
measure of the number of different species in a community
41
describe what represents biodiversity
* species richness
* number of organisms within each species
* in the geographical region
42
describe wether biodiversity increases from the poles to the equator and why
* the biodiversity increases.
* This is in part due to increasing light intensity, but water availability is alsoimportant: a hot desert has a lower biodiversity than a temperate forest.
* The higher light intensity ensures that the solar energy entering these ecosystems is higher, allowing greater photosynthesis, but in the desert, the lack of water
will limit plant growth and hence biodiversity.
43
what are the factors affecting biodiversity and explain why for each factor
1. Succession: the composition of a community changes over time as
different species colonise.
2. Natural selection: see page 77.
3. Human activity: pollution, overfishing, and deforestation have all taken
their toll on biodiversity by the physical removal of species or destruction of their habitats. Farming has also played a part, as monoculture involves the growing of a single species of crop, e.g. maize, so other species are
removed to maximise yields.
44
why are people worried for reductions in biodiversity in plant species
* provide staple foods eg rice and wheat
* provide raw materials eg cotton
* many drugs are derived from plants eg vincristine which is used to treat cancer and many have yet to be discovered
45
what is an index of diversity
* measure of number of individuals of each species and the number of species
46
gene
is a section of DNA on a chromosome that codes for a particular polypeptide
47
allele
different form of the same gene
48
phenotype
what an organism looks like its characteristics
49
gene pool
total number of alleles within a population
50
what is a locus
a genes position on a chromosome
51
when does a locus show polymorphism
if it has two or more alleles that cannot be accounted for by mutation alone resulting in two or more different phenotypes
52
why should sampling be random
to reduce bias
53
describe how ABO group shows polymorphism
In ABO blood grouping, the gene responsible for producing antigens on the surface of red blood cells has three different alleles: A, B and O. In some parts of the world, the frequency of the O allele is very high, accounting for over 99% of the gene pool. In other countries, the proportion of A and B alleles is
much higher: this represents a higher biodiversity.
54
how would u sample terrestrial animals when assessing biodiversity
* mark - release - recapture
* lincoln index
* Animals are captured and marked (it is
important that they are not harmed or made
more visible to predators) and then released.
Once animals have had a chance to reintegrate with the population, e.g. 24 hours, the traps are reset.
The total population size can be estimated using the number of individuals captured
in sample 2, and the number in that sample that are marked (i.e. caught before).
55
what do you have to assume with mark - release - recapture technique
Have to assume that no births/deaths/ immigration/emigration have occurred during the time between collecting both samples.
56
how can you sample freshwater invertebrates when assessing biodiversity
* use kick sampling and use simpsons index
* collect and identify invertebrates from a given area using a quadrat and a net. Kick or rake the area, e.g. 0.5m2 for a set period, e.g. 30 seconds, and collect invertebrates in a net downstream.
Release invertebrates carefully.
Use Simpsons Index to calculate diversity.
57
describe how you can sample plants when assessing biodiversity
* Quadrats and
transects
* Estimate percentage area cover of different
plants using a quadrat divided into 100 sections. Measure plant diversity by counting number
of plants in a quadrat, e.g. 1m2
.A transect is a length of rope that can be used to measure intervals along an environmental gradient, e.g. distance from a woodland, along which quadrats can be
placed.
58
what are the three adaptations which may arrive from natural selection and give an example for each
1. Anatomical, e.g. beak shape in finches.
2. Physiological, e.g. haemoglobin with a higher affinity for oxygen as found
in llamas that live at high altitudes.
3. Behavioural, e.g. nocturnal animals.
59
what is evolution
process by which new species are formed from pre existing ones over a period of time
60
what led to the idea of natural selection
Darwin’s observations of variation within a population led to the development of the idea of natural selection. Darwin recognised that species changed.
61
what does natural selection result in
* species that are better adapted to their environment
62
