Chapter 7 Classification & Biodiversity Flashcards
Define phylogenetic
Reflecting evolutionary relatedness
What is a phylogenetic tree?
A diagram showing descent, with living organisms at the tips of the branches and ancestral species in the branches with branch points representing common ancestors. The length of the branches indicate the time between common ancestors.
Define taxonomy
The identification and naming of organisms
Define classification
Putting items into groups
Define hierarchy
A system of ranking in which small groups are nested components of larger groups
Define taxon
Any group within a system of classification
Why is phylogenetic classification described as discrete and hierarchal?
Taxa are discrete meaning an organism belongs in one taxon and in no other.
Classification has bigger taxa containing smaller taxa, therefore hierarchal
Why is a classification system needed?
Allows the inference of evolutionary relationships.
We can predict the characteristics of new animals that are discovered based on our general understanding of other similar animals.
Easier to communicate
Rate of extinction is easier to calculate by counting families rather than species.
What are the 3 domains?
Eubacteria
Archaea
Eukaryota
What are the 5 kingdoms?
Animalia Plantae Fungi Protictista Prokaryota
What are the characteristics of prokaryotes?
Unicellular, no nucleus, mesosmes in some, 70s ribosomes, no endoplasmic reticulum, no vacuoles, peptidoglycan Cell walls, saprophytic/parasitic or autotrophic, no nervous coordination.
What are the characteristics of protoctista?
Eukaryotic, unicellular/multicellular, nucleus, mitochondria, chloroplasts in some, 80s ribosomes, endoplasmic reticulum, vacuole in some, cellulose cell walls in some, some autotrophic and some heterotrophic, no nervous coordination
What are the characteristics of plants?
Eukaryotic, multicellular, nucleus, mitochondria, chloroplasts, 80s ribosomes, endoplasmic reticulum, large central permanent vacuoles, cellulose cell wall, autotrophic, no nervous coordination
What are the characteristics of fungi?
Eukaryotic, unicellular/hyphae, nucleus, mitochondria, no chloroplasts, 80s ribosomes, endoplasmic reticulum,large central permanent vacuole, chitin Cell walls, saprophytic or parasitic, no nervous coordination
What are the characteristics of animals?
Eukaryotic, multicellular, nucleus, mitochondria, no chloroplasts, 80s ribosomes, endoplasmic reticulum, small scattered temporary vacuoles, no cell wall, heterotrophic, nervous coordination.
Define homologous structures
Structures in different species with a similar form and developmental origin, but different function.
What is divergent evolution?
Where a common ancestral structure has evolved and performs different functions. This is supported by homologous structures.
What is an example of a homologous structure?
The pentadactyl limb (having five digits). It’s basic structure is the same in all four classes (mammals, reptiles, birds, fish and amphibians). However, the limb has adapted for different functions.
Define analogous structures.
Structures in different species that have a corresponding function, but have a different form and developmental origin.
What is convergent evolution?
Structures evolve similar properties, but have different developmental origins.
What are the 4 ways of assessing relatedness with genetic evidence?
DNA sequences
DNA hybridisation
Amino acid sequences
Immunology
How do DNA sequences assess relatedness?
More closely related species show 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.
How does DNA hybridisation assess relatedness?
DNA from two species are extracted, separated and cut into fragments. The fragments are mixed and where they have complementary base sequences, they hybridise together. The more closely related species have more hybridisations.
How do amino acid sequences assess relatedness?
The degree of similarity in the amino acid sequence of the same protein in two species will reflect how closely related they are.
How does immunology assess relatedness?
If you mix the antigens of one species with specific antibodies of another, the antigens and antibodies make a precipitate. The closer the evolutionary relationship, the more precipitate formed.
Define species
A group of organisms that can interbreed to produce fertile offspring.
What is the morphological definition of species?
If two organisms look very similar, they are likely to be in the same species. Sexual dimorphism (physical differences between males and females) must be taken into account.
What is the reproductive definition of species?
Two organisms are in the same species if they can interbreed to produce fertile offspring.
Define binomial system (also called binomial nomenclature)
The system of giving organism a unique name with two parts, the genus and species.
What are the advantages of the binomial system?
Unambiguous naming.
Based on Latin, can be used globally.
Implies that two species sharing part of their name are closely related.
How do you use the binomial system?
The genus is the first word and has a capital letter
The species name comes second and does not have a capital letter
The first time the genus name is used in a text it is written in full, but if used again, the genus name may be abbreviated
Both names are printed in italics or underlined when hand-written
Define biodiversity
The number of species and the number of individuals in each species in a specified region
What are the three reasons biodiversity can increase or decrease?
Succession (time)
Natural selection
Human influence
What is the equation for the simpsons index?
1-[n(n-1)/[N(N-1)
n=individuals in each species
N= total amount of species
Define polymorphism
The occurrence of more than one phenotype in a population that cannot be accounted for by mutation alone.
How can number of alleles assess biodiversity?
A genes position on a chromosome is its locus. A locus can show polymorphism if it has two or more alleles at frequencies greater than would occur by mutation alone. If a gene has more alleles it is more polymorphic, therefore more biodiversity as more phenotypes are possible. For example, if gene T has two alleles, but gene S has 31 alleles, gene S has a greater biodiversity.
How can the proportion of alleles assess biodiversity?
If we consider the whole gene pool, if there is a greater variation of alleles present in a population, the greater the biodiversity in relation to the characteristic associated with that gene.
How does DNA fingerprinting assess biodiversity?
Comparing the number and position of bands in the DNA profiles of a population. More differences indicate a greater biodiversity.
What is natural selection?
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.
What are the three types of adaptive traits that can occur as a result of natural selection?
Anatomical
Physiological
Behavioural
