What is variation
when no two individuals of a population are identical in their traits
What is taxonomy
the science of categorising life
What are the two types of variation
continuous
discontinuous
Example of continuous variation
height
Example of discontinuous variation
blood type
What are the two ways of categorising species?
morphological
physiological
Morphological species
Classified by physical characteristics.
Organisms with shared traits
Sexually and asexually reproducing organisms and fossils
Who first published the morphological species definition
Carolus Linnaeus, 1735
Biological species
a group of organisms that can breed and produce fertile offspring
cannot apply to fossils, hybrids, bacteria containing DNA from multiple sources
Who proposed the biological species definition
Ernst Mayr, 1942
What is binomial nomenclature
two-name system of classification
Binomial nomenclature structure
First word: genus name (Capitalised)
Second word: species name (lowercase)
has to be underlined in exams.
Homo sapiens (italics)
When are related populations different species in biological species concept
when they are reproductively isolated.
doesn’t work when two isolated populations of the same species are slowly evolving to be different. BECAUSE unsure if viable offspring can be produced.
When are related populations different species in the phylogenetic species concept
When they differ in a trait or gene
Problems arise when populations exhibit variation, so species would spilt into many species.
Difference in traits is subjective
Name the haploid cells and diploid cells in humans, chimpanzees, and bonobos.
number of chromosomes is characteristic of a species
humans, 23 + 46
chimpanzees, 24 + 48
bonobos, 24 + 48
What is a karyogram
representation of all chromosomes in a cell arranged according to size, centromere position, banding pattern.
arranged in decreasing order of length
Describe XY chromosomes
One long, one short
What are the two hypotheses to how the chromosome number of humans changed over time from the common ancestor between humans and gorillas.
- a complete chromosome disappeared
- two chromosomes fused to become a single chromosome.
3 evidence that supports the hypothesis that human chromosome 2 originated from the fusion of chromosomes 12 and 13 from an ape ancestor
- chromosome 2 sequence is almost identical to chimpanzee sequences found on two different chromosomes
- chromosome 2 has one centromere and one remnant of a centromere
- chromosome 2 has telomeres in the centre. Telomeres should only appear at the end of the chromosome.
When would the fusion of the chromosomes have happened?
Evidence does not say we descended from chimpanzees.
The fusion of the chromosome would have happened after the speciation split of a common ancestor that led to the evolution of chimpanzees in one lineage and the evolution of humans in another.
What is a genome
the entire genetic information in an organism
How is a genome of a species an example of diversity
shows variation between members of a species
Example of genome showing variation
SNPs occur due to mutations.
Source of difference across individuals of a species.
The genes of a species are the same, but the alleles??
will vary
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1.1- Intro to Cells17
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1.2- Cell Types29
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1.3- Stem Cells18
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1.4- Membrane Structure23
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1.5- Membrane Transport29
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2.1- Water25
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2.2- Organic Compounds14
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2.3- Carbohydrates14
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2.4- Lipids36
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2.5- Proteins17
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3.1- Transcription20
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3.2- Translation12
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3.3- Gene Mutations42
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3.4- DNA Replication11
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3.5- Cell Division18
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4.1- Respiratory Systems41
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4.2- Circulatory system20
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4.3- Immune System44
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4.4- Nervous System31
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4.5- Reproductive System45
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5.1- Integration48
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5.2- Regulation26
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6.1- Plant Structure16
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6.2- Transpiration17
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6.3- Germination32
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7.1- Evolution22
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7.2- Natural Selection19
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7.3- Classification30
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7.4- Extinction35
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8.1- Population29
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8.2- Communities21
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8.3- Habitats25
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8.4- Ecosystems30
