2.1 - all organisms are related through their evolutionary history Flashcards
what are branch points on a phylogenetic tree?
they represent common ancestors of the organisms in the branches above
what are shown at the tips of branches of phylogenetic trees?
these are the living organisms alive now
what does it mean when the organisms are close together on a phylogenetic tree?
they have a common ancestor
what are the levels of classification?
domain
kingdom
phylum
class
order
family
genus
species
(dear kate please come over for great spagetti)
what is the biggest level of classification?
domain
why is it advantageous to have a phylogenetic classification system?
- allows us to infer evolutionary relationships
- we can communicate quicker about different organisms
- easier to count the families
what are the three levels of domain?
eubacteria
archaea
eukaryota
what is eubacteria?
familiar bacteria, prokaryotes
what is acheaea?
bacteria with unusual metabolism, prokaryotes
what is eukaryota?
all eukaryotic organisms
what are the five kingdoms each level of domain contain?
prokaryota
protoctists
fungi
planta
animalia
what are the characteristics of prokaryota?
all bacteria:
- microscopic, single-celled, no membrane bound organelles, cell wall is made of peptidoglycan
what are the characteristics of protocista?
eukaryotic organisms - single celled, no tissue differentiation.
what are the characteristics of fungi?
heterotrophic eukaryotes - cell wall made of chitin, reproduce by spores
what are the characteristics of planta?
multicellular eukaryotes, photosynthetic, cellulsoe cell wall
what are the characteristics of animalia?
multicellular eukaryotes, hetertrophic, no cell wall with a nervous system
what is a pentadacytl limb?
these have five digits, these show homologous features therefore suggesting a common ancestor which has evolved to perform different functions
what is homologous structures?
the same structural origin, but developed to perform different functions
what is analogous structures?
come from different origins but developed a similar structure over time due to necessity
how does the DNA base sequence demonstrate genetic evidence for relatedness?
closely related species have more similarly related DNA base sequences which confirm evolutionary relationships between organisms
how does DNA hybridisation demonstrate genetic evidence for relatedness?
comparing how related two organisms are by extracting DNA from each and hybridising them and if they have complimentary bases, finds out what percentage of their DNA is in common and bonded together
how do you compare amino acid chains?
count how many each chain has in common, therefore highlighting which pair has the most recent common ancestor and hence is not the original ancestor
how does the amino acid sequence demonstrate genetic evidence for relatedness?
how closely related two organisms are by comparing their amino acid sequence and whethe rit is similar
how does immunology demonstrate genetic evidence for relatedness?
if you mix the antigen of one species with the specific antibodies of another the antigen and antibodies will form a precipitate, the closer they are, the more preciptate.
what is the morphological definition of species?
if two organisms look the same, they ar elikely to be the same species
what is the reproductive definition of species?
if two organisms can reproduce to form fertile offspring, they are the same species
what is a sterile hybrid?
the offspring of two organisms that are not the same, but closely related species but are infertile
what does the binominal system allow?
discover and describe biological diversity,
evolutionary relationships,
classify organisms to reflect their evolutionary relationships
what is the binomial system?
this gives each organism a specific and unique name:
Genus, species - G.species
GENUS IS ALWAYS CAPITAL
species is always lower case
what is the definition of biodiversity?
the number of species and the number of organisms in a given environment
how does succession alter biodiversity?
communities of organisms changes its habitatm making it more suitable for other species - overall decreases animal biodiversity and increases plant biodiverity
how does human influence change biodiversity?
makes environment less hospitable to living organisms, decreases biodiverisity and can lead to extinction
what is extinction?
this is the loss of species
what can cause extinction?
change in habitat, increased competition, new diseases
what is conservation?
defined by actively planning to protect a species or habitat
what are the methods of conservation?
- trade restrictions on endangered species
- national parks
- government agencies
- captive breeding
- government legislation
- seed banks
how are different species important to humans?
- sources of food
- provides raw material like wood
- useful chemicals/pharmaceuticals
- disease resistant genes can be used in genetically modificated crop
how do we assess biodiversity at the population level?
simpsons index:
S = 1 - ∑n(n-1)
N(N-1)
N i s the total number of organisms present
n is the number of each species
what is polymorphic loci?
assessment of genes and alleles of biodiversity, giving focus on alleles in the genetic pool of a population
what is a locus?
a genes position on a chromosome
what is polymorphism?
the presence of two or more forms or alleles of a gene within a population, leading to variation in traits
what does it mean when a gene has lots of alleles?
its locus is more polymorphic than if there were fewer
what is a persons genetic profile?
a unique pattern to each individual, related to the base sequences of their DNA
what is an SNP’S?
single nucleotide polymorphism, a singular base that mutates so a person has DNA in entirety
what is a HVR?
hyper-variable regions - long base sequences of non-coding DNA
would there be less or more genetic variation in a constricted biodiversity?
less
what does it mean when a population has more SNP’s/HVR’s?
more differences in its DNA profiles
what are the steps to collect DNA?
- the DNA molecule is cut using a restriction enzyme (endonuclease)
- this enzyme cuts the DNA at specific base sequences in a process called electrophoresis
what is a bottleneck?
mass extinction
what is natural selection?
gradual process in which inherited characteristics become more/less common in a population, in response to a change in environment.
what is some reasons for evolution?
fossil evidence - supports natural selection
what is an example of natural selection?
shapes of birds beaks change depending on the food/diet of that bird, that an ancestor years ago had developed the specialised beak over time
what are the 6 stages of natural selection?
mutation
variation
competitive advantage
survival of the fittest
reproduction
pass advantageous genes to offspring
what is a misssing link?
that species evolve gradually over time leaving behind a missing link (the previous form of that species)
describe natural selection?
- habitats change
- individuals with alleles that are more suited will survive
- hence reproduce more successfully due to their advantage
over time organisms will inherit those characteristics -NATURAL SELECTION
how are fossils dated?
radiocarbon method, as fossils are formed in sedimentary rocks and in layers of strata
what is creation?
that missing links is evidence of special creation of intelligent design
what is an anatomical adaptive trait?
- organisms with optimised bodies (e.g. sharks with streamlined bodies)
what physiological adaptive trait?
- adaptations to avoid wasting energy (e.g. leaves falling off plants to reduce water loss)
what is a behaviour adaptive trait?
- an animal behviour that is suited to it for efficiency (e.g. peacocks dancing to attract a mate)
