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(Two names)
Ovis canadensis
Ovis gmelini
Ovis aries
Genus: a group of species that share common characteristics but may not be able to interbreed.
Species: a group of organisms in the same genus that are able to interbreed to produce fertile offspring.
Taraxacum officinale or dandelion
A red kangaroo, Macropus rufus.
System of names for species is universal (used by all) and has been agreed and developed at a series of congresses. Each time a new species is discovered, it is given a scientific name using the binomial system.
Individuals of the same species share more morphological characteristics than members of different species.
A biological species is a group of organisms that can reproduce with one another in nature and produce fertile offspring.
Karyogram from Karyotyping
Hypothesis: at some point chromosomes 12 and 13 of the great ape karyotype fused, creating what is now chromosome 2 in the human karyotype.
Evidence:
Before these two left us...
Genome:
All of the genetic information of an organism.
Within a species there is usually only single-nucleotide polymorphisms (SNPs) that contribute to variation and diversity.
The process of determining the order of the bases in an organism’s genetic code.
"A series of paired opposing statements which guide the user to the identity (or allows the classification) of an item or organism."
5.3.S1 Construction of dichotomous keys for use in identifying specimens.
HL
There are also many intermediate taxa, such as subfamilies and superorders
The perspective of classification has shifted from a system based on similarities in appearance and behaviour, to a more precise and detailed one based on amino acid sequences++
1. It reflects the evolutionary relationships among different organisms
2. It reflects the process of evolution
3. It can be used to make predictions about the characteristics of organisms
4. It helps us to understand the diversity of life on Earth
Cladogram
HL
"A group of organisms that have evolved from a common ancestor"
Clade: A group of organisms, both extant and extinct that share an ancestor.
Cladistics: A system of classifying organisms according to shared characteristics, based on ancestry.
Cladistics: A system of classifying organisms according to shared characteristics and geneteic evidence, based on ancestry.
Cladogram: A diagram that shows the evolutionary relationship of a group of organisms.
Remember:
Evidence for which species are part of a clade can be obtained from the base sequences of a gene or the corresponding amino acid sequence of a protein.
Cladograms are representations of when divergence of species into clades occurred along the evolutionary chain
Convergent evolution vs Divergent evolution
Homologous structures vs Analogous structures
"A figurative term for a technique that uses the mutation rate of biomolecules to deduce the time in prehistory when two or more life forms diverged."
"There is a positive correlation between the number of differences between two species and the time since they diverged from a common ancestor. That is, the longer the time period since the two species separated, the more differences there will be when the DNA of the two species is compared."
The conversion of differences in base sequence to units of geologic time usually needs to be checked against the fossil record.
If a particular mitochondrial gene accumulates base sequence mutations at a rate of 3 every 5 million years, about how long ago would two species have shared a common ancestor if their gene base sequence differs by 13 bases?
If you know that 3 mutations occur per 5 million years, then 1 mutation occurs per 5/3 million years.
So, 13 mutations occur over 13 × 5/3 million years = 21.7 million years.
The two species would have shared a common ancestor around 21.7 million years ago.
The oldest fossil of a specific species that is known to exist can be used
Outgroop
Root
Node
Terminal branch : Extant species
1. The branching pattern is assumed to represent the evolutionary relationship between species.
2.If extinct species are included, information must be given on whether the cladogram is based on morphology only because DNA generally is not available for the analysis, although there are some exceptions to this.
3. The more nodes there are between species, the more distant their relationship.
4. Mutations at the DNA and protein level are assumed to occur at a constant rate. For example, 1 base change per 109 years – this may seem like a long time, but remember there are billions of bases in genomes.
5. Some cladograms are drawn to scale, that is the length of the branches is proportional to the time since divergence.
5.3.A1 Classification of one plant and one animal species from domain to species level
5.3.A2 Recognition features of bryophyte, filicinophyta, coniferophyta, and angiospermophyta.
Filicinophytes
Coniferophytes
Bryophytes
Bryophytes
Angiospermophytes
Filicinophytes
Coniferophytes
5.3.A3 Recognition features of porifera, cnidarian pletyhelmintha, annelida, Mollusca, arthropda and chordata.
Annelida
Mollusca
Cnidaria
Porifera
Platyhelminthes
Arthropoda
Chordata
5.3.A4 Recognition of features of birds, mammals, amphibians, reptiles and fish
Chordata is a large phylum of animals that includes the vertebrates together with tunicates (sea squirts) and lancelets. They are distinguished by the possession of a notochord at some stage during their development.
Fish
Aves (Birds)
Amphibia
Mammalia
Reptilia