2.1 - Biodiversity Flashcards
Classification def?
putting items into groups
Phylogenetic def?
Reflecting evolutionary relatedness
Phylogenetic method?
grouping closely related organisms together
Organisms in the same group?
have a more recent common ancestor with each other than with organisms that are not in their group
If closely related?
may show physical similarities
Chimpanzee, gorilla, human and banana?
the chimpanzee, the human + gorilla - have a more recent common ancestor than any of them does with the banana.
Puts the chimpanzee, human and gorilla into group that does not include the banana
Chimpanzee + human have more recent common ancestor than either has with gorilla
puts human + chimpanzee into group that excludes gorilla
How can these be shown?
phylogenetic tree
Phylogenetic tree?
diagram that shows descent with living organisms at the tips of the branches and ancestral species in the branches and trunk with branch points that represents common ancestors
lengths of branches - indicate the time between branch points
In a phylogenetic tree?
further up the diagram you go, the further forward in time
species at top exist now
those in trunk and branches are no longer alive
branch points - represent common ancestors of organisms in the branches
diagram reminds that current species in 3.8 billion year history of life
Hierarchy def?
system of ranking in which small groups = nested components of larger groups
Taxon?
any group within a system of classification
Hierarchy of biological classification?
Domain>Kingdom>Phylum>class>order>family>genus>species
Example of how the hierarchical classification system is applied?
Domain - Eukaryota
Kingdom - Animalia
Phylum - Chordata
Class - Mammalia
Order - Primates
Family - Hominidae
Genus - Homo
Species - Sapiens
Moving down the hierarchy?
from domain to species, organisms in a taxon are more closely related
Moving up the hierarchy?
from species to domain, members of a taxon are less closely related
Taxa are discrete?
at any level of classification , an organism belongs in one taxon and in no other.
Why do we need a classification system?
A phylogenetic classification system allows us to infer evolutionary relationships. If 2 organisms are so similar that we put them in the same taxon, we infer they are closely related
If new animal is discovered with a beak and feathers, we predict some of its other characteristics based on general understanding of birds
when we say bird, it is easier than saying vertebrate egg laying biped with a 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
What is our system for classification depends on?
our current knowledge
any system we use = tentative and may be altered as our knowledge advances
Domain?
largest taxon and all living things belong in one of 3 domains
domains - originally defined on the bases of rRNA base sequences
More modern methods of analysis also consider similarities in DNA base sequence
Eubacteria?
these are the familiar bacteria such as E.coli and Salmonella
They are prokaryotes
Archea?
these are bacteria and often have unusual metabolism
e.g some generate methane
Many are extremophiles
Include a lack of molecular oxygen, very high pressure, very high temp, or very high or low pH
Eukaryota?
plantae, animalia,fungi and protoctista
What is the 5 kingdom system?
5 kingdom system classifies organisms on the basis of their physical appearance
5 kingdoms?
Eubacteria and Archaea - 1 kingdom
Prokaryotae and the other 4 organisms contain eukaryotes organisms
Domain def?
the highest taxon in the biological classification, one of the three major groups into which living organisms are classified
Kingdom def?
all living organisms are classified into 5 kingdoms depending on their physical features
Phylum def?
subdivision of a kingdom, based on a general body plain
Class?
sub - group of a phylum
e.g Mammalia form a class within the phylum Chordata
insects = class within the phylum Arthropoda
Phylum?
sub group of a kingdom
members of each phylum have a distinct body plan
e.g members of the phylum Annelida = soft bodied and segmented ; members of the Arthropods have a chitinous exoskeleton and jointed limbs.
Chordata - contains vertebrates
Order?
sub group of a class - Lepidoptera
Order containing butterflies and moths is in the class insects
Family?
group within an order
Flower families = most familiar such as rose family rosaceae
Genus?
a group of similar organisms such as the genus Panthera, containing lions and tigers
Species?
a group of organisms sharing a large number of physical features and able to interbreed to make fertile offspring
Genus def?
a taxon containing organisms with many similarities but enough differences that they are not able to interbreed to produce the offspring
Species def?
a group of organisms that can interbreed to produce fertile offspring
Prokaryota?
microscopic
kingdom - contains all the bacteria
Archaea and cyanobacteria
Protoctista ?
some protoctista have only 1 cell and these are the main component of plankton
others are colonial
some have many similar cells
these = seaweeds, or algae, such as the sea lettuce
Plantae?
mosses, horsetails and ferns reproduce with spores
conifers and flowering plants reproduce with seeds
Fungi?
yeasts = single celled
moulds such as penicillium and mushrooms such as Amanita muscaria have hyphae that weave together to form the body of the fungus, a mycelium
In some fungi, cross - cell walls called septa, dub divide the hyphae
Homologous structure def?
structures in different species with a similar anatomical position and developmental origin derived from a common ancestor
Pentadactyl def?
having 5 digits
Divergent evolution?
the development of different structure over long periods of time from the equivalent structures in related organisms
The theory of evolution?
suggests 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
more similar 2 organisms are, more recently they = assumed to have diverged
Pentadactyl limb of the vertebrate?
basic structure = the same in all 4 classes of terrestrial structures, amphibians, reptiles, birds and mamals
However. the limbs of the different vertebrates have adapted and have different functions - grasping, walking, swimming and flying
Examples = human arm, wing of a bar, flipper of a whale, wing of a bird, leg of a horse
Divergent evolution?
a common ancestral structure has evolved and performs different functions
Convergent evolution def?
development of similar structures is unrelated organisms over long periods of time related to natural selection of similar features in a common environment
Analogous structures def?
have corresponding function and similar shape but have a different developmental origin
Convergent evolution?
where structures evolve similar properties but have different developmental origins
Such structures = analogous
DNA sequences?
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, show more similarly in their DNA base sequences than those who are more distantly related
DNA analysis has confirmed evolutionary relationships and corrected mistakes made in classification based on physical characteristics
DNA hybridisation?
involves comparing DNA base sequences of 2 species
to work out how closely related 2 species of primates for example humans
Homo sapiens and chimpanzee
DNA from both = extracted, separated into single strands and cut into fragments
Fragments from the 2 species = mixed and where they have complementary base sequences, they hyribidse together
Amino acid sequences?
the sequence of amino acids in proteins is determined by the DNA base sequence
Degree of similarity in the amino acid sequence of the same protein in 2 species will reflect how closely related they are
Immunology?
the proteins of different species can be compared using immunological techniques.
If you mix the antigens of 1 species. such as the blood protein albumin with specific antibodies of another, the antigens and antibodies coagulate
closer the evolutionary relationship, the more coagulation occurs
Morphological definition?
the 2 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 the lions not the female lions
Reproductive definition?
another way of defining a species states that the 2 organisms are in the same species if they can interbreed to make fertile offspring
Taxomonomy def?
the identification and naming of organisms
Purpose of taxonomy?
discover and describe biological diversity
investigate evolutionary relationships between organisms
classify organisms to reflect their evolutionary relationships
Binomial system def?
the system of giving organisms a unique name with 2 parts
genus and species
3 advantages of the binomial system?
unambiguous naming
based on latin, can be used all over the world
implies that 2 species sharing part of their name are closely related
panthera leo
panthera tigris
How to use the binomial system?
each organism has 2 names
its genus and species
genus = first name and capital letter
species comes second and does not have capital letter
first time the scientific name = used in text, it is written in full
Panthera tigris
If used again, may be abbreviated , P tigris
Both names = printed in italics or underlined when hand written
Biodiversity def?
number of species and the number of individuals in each species in a specified region
What does biodiversity refer to?
the number of species - species richness
Number of organisms within each species - species evenness
vary enormously, depending on where and when you are looking
biodiversity = not constant
Spatial variation?
number of species and the number of organisms depend in part on the environment
Examples?
more plans grow at high light intensity than low light intensity so at a bright environment can support more herbivores and therefore more carnivores than a dull one
more energy flowing through an ecosystem produces more species + more individuals
means that equatorial regions have a much higher biodiversity than polar regions
Biodiversity can increase or decrease for 3 main reasons?
succession
natural selection
human influence
Succession?
over time, a community of organisms changes its habitat, making it more suitable for other species
change in composition of a community over time = succession
increases biodiversity but ultimately decreases plant biodiversity
Natural selection?
can generate and change biodiversity
Human influence?
Tropical rainforests, farming, roads and industry have destroyed habitats, reducing the numbers of individuals and driven to extinction many species have 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
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 increasing temp related to climate change has increased the area of deserts.
sahara desert = expanded and large area of australia + north america - vulnerable
Rivers = polluted with industrial chemicals
Significance of reduced biodiversity?
a small number of plants and animals = used to support human civilisation
medicinal drugs = derived from plants + fungi for example aspirin, statins, antibiotics
Living organisms provide important raw materials e.g rubber and cotton
As biodiversity decreases?
we lose potential new foods and sources of new useful characteristics to breed into crops such as disease resistance
potential for discovering new medicinal drugs and new raw materials = compromised
Assessing biodiversity?
at production level produces a biodiversity index which can be used to monitor the biodiversity of a habitat over time and to compare biodiversity in different habitats
Example of assessing biodiversity?
Simpson’s diversity index
which describes the biodiversity of motile organisms such as the invertebrates in a stream
Commonest way of calculating the index gives a numerical value and the higher the value, the higher the biodiversiy
Calculation?
1 - Sum of n(n-1)
/ N(n-1)
N = the total number of organisms present
n = the number in each species
Polymorphism def?
this occurrence of more than one phenotype in a population, with the rarer phenotypes at frequencies greater than can be accounted for by mutation alone
what does an examination of genes and alleles give?
an assessment of biodiversity at the genetic level
approach focuses on all the alleles present in the gene pool of the population and not the individuals
Locus?
a gene’s position on the chromosome
what does a locus show?
polymorphism if it has 2 or more alleles, with the rarer alleles at frequencies greater than would occur by mutation alone
Low biodiversity for that gene?
if 98 % of all the alleles of a particular gene are the same recessive allele
If a gene has more alleles?
its locus is more polymorphic than if there were fewer alleles
In some plants?
Gene T controls height - 2 different alleles
Gene S controls whether or not pollen can germinate on the stigma of a flower of the same species
Gene S has a greater biodiversity than gene T as more phenotypes are possible for genes S than T
High biodiversity for that gene?
If only 50% of the alleles in the gene pool were recessive, 50% would be other alleles
DNA fingerprinting?
sometimes only 1 base differs
these single base differences are called SNPS
single
nucleotide
polymorphism
also regions of DNA that vary generally about 20-40 base sequences long often repeated many times
unique lengths of non-coding DNA are called hyper-variable regions or short tandem repeats
Genetic or DNA fingerprint or profile?
terms for a pattern unique for each individual, related to the base sequences of their DNA
What does comparing the number and position of the bands in the DNA do?
indicates how similar or different their DNA sequences are
More different SNPs and HVR’s a population has, the more differences there are in its DNA fingerprints
More differences indicate a greater biodiversity
In a biodiverse population, DNA fingerprints show a lot of variation
Natural selection def?
the gradual process in which inherited characteristics become more or less common in a population, in response to the environment determining the breeding success of individuals possessing those characteristics
Mutation?
differences in DNA
Variation?
different physical appearance, biochemical function or behaviour
Competitive advantage?
some are more suited to the environment than others and outcompete rivals for resource’s
Survival of the fittest?
the more suited to the environment survive better
Reproduction?
the more suited to the environment have more offspring
Pass advantageous alleles to offspring
offspring inherit the advantageous alleles, so they are also suited to the environment
How does natural selection decrease biodiversity?
happens 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 plants cannot survive
then the herbivores die, so the carnivores die
Natural selection selection decreases the biodiversity and species may become extinct
Adaptation?
change in a species as a useful characteristic becomes more common
Useful characteristic = adaptive trait
Anatomical traits?
where the animal is developed to their function
e.g sharks have streamlined bodies, more efficient at catching food or prey
Physiological traits?
refers to their biological function
e.g mammals are endothermic and must avoid wasting energy trying to maintain body temp in the cold
during hibernation, a hedgehog resets its body thermostat as hibernation requires less energy
Behavioural traits?
Animals change their behaviour to fit their function
e.g hawthorn, the flowers in spring when pollinating, insects have emerged. If flowered earlier, would not be pollinated
