U4 AOS2 Flashcards
Allele Frequency
The proportion of certain alleles in the gene pool
Genotype
The genetic composition of an organism at a particular gene locus
Population
Members of one interbreeding species living in one region at a certain time
Gene pool
Total genetic info of a population
Genotype
Total set of genetic info
Polygenetic
Controlled by multiple genes
Monogenentic
Controlled by 1 gene
Allele Frequency
2(#of homo) + Humber of hetero
÷ total #
Selective pressures
A random event that alters a populations gene pool
Natural selection
Changes in allele frequencies due to the influence of selection pressures
Genetic drift
Fluctations in the frequency of alleles in a population as a result of random events
Heterozygous
Aa
Homologous Dominant
AA
Homologous Recessive
aa
Bottleneck Effect
reduction of genetic diversity in a population due to a random event - natural disaster.
Survivors live by chance
Founder Effect
reduction of genetic diversity in a population due to a small group of individuals from a larger population moving and making a new popualtion
Gene Flow
the flow of alleles in and out of a population
Immigration
movement into a population to increase genetic diversity
Emigration
movement out of a population to decrease genetic diversity
Interbreeding
2 individuals from different populations breed and have healthy and fertile offspring
Three factors that cause mutations
Mutagens (physical and chemical) and pathogens
Mutagen
an agent that causes mutations in the DNA
When is a mutation heritable
in the germline cells
When is a mutation NOT heritable
in the somatic cells
Somatic mutations
Mutations that occur in body cells and are not heritable by offspring
Germline mutations
Mutations that occur in gametes and are thus heritable by offspring
Point mutation
Smallest gene mutation, where only one base is affected, being substitutions, insertions or deletions
Silent mutation
When a mutation has no effect on the expression of the genetic material because it still codes for the same amino acid
Missense Mutation
A mutation that changes the codon, which now codes for a different amino acid
Nonsense mutation
A mutation that causes the formation of a premature stop codon
Frame shift mutation
A point mutation that alters the sequence of bases following it
Aneuploidy
Gain or loss of a single chromosme
Polyploidy
When an organism or cell has the wrong number of sets of chromosomes (such as 3 of each chromosome instead of 2 in humans)
Divisions of geological time scale from smallest to largest
Epochs, then periods, then eras, then eons
What are fossils?
The preserved remains, impressions or traces of organisms
Fossil record
The total number of fossils that have been discovered and provide evidence of evolution
Index fossils
Fossils of geologically short-lived species that have a limited occurence in the fossil record and are thus useful for relative dating
Transitional fossils
A fossil that shows traits from ancestors and descendants. Shows Relationship.
Species
A group of individuals that are able to interbreed under natural conditions to form viable and fertile offspring
Prezygotic isolation factor examples
**Before Fertilisation occurs; **
Temporal- day active VS night active
Geographic - mountains vs valleys
Behavioural - rituals
Mechanical - different sex organs
Post-zygotic isolation factor examples
** After Fertilization occurs;**
Incompatibility of gametes, inviability of zygote and sterility of hybrid
Artificial / Selective breeding
When humans deliberately breed individuals with desirable traits in order to produce offspring that possess these desirable traits
Homologous structures
Structures found in different species that are similar but have different functions
Vestigial structure
A structure that no longer has a purpose in the organism but did in its ancestor
Allopatric speciation
(FInches)
When a geographical barrier prevents gene flow between populations, which evolve over time due to different selection pressures and natural selection favouring different traits as offering selective advantages, eventually the populations would not be able to produce fertile or viable offspring and would be different species
Sympatric speciation
(Palms)
When speciation occurs without a geographical barrier, and another factor prevents gene flow
Antigenic drift
When mutations in a pathogen’s nucleic material results in small changes to its antigens
Antigenic shift
When multiple strains of a virus combine to form a new strain of the virus with antigens from each of the original strains
Classification of humans
Mammals, primates, hominoids, hominins
Structural morphology
The study of the similarities and differences between the structures of species to determine relatedness
Hominins vs Hominids
Hominins are humans and all ancestors, Homininds are humans, great apes, and ancestors
Why can’t carbon 14 dating be used to date rocks?
Carbon 14 dating can only be used with organic material
Optimal conditions for the formation of fossils
Rapid burial by deposit of sediment layers, low temperature and anaerobic conditions that are not disturbed and are free of decomposers or scavengers
How are monoclonal antibodies produced?
- Antigens that the monoclonal antibodies are designed to act on are injected into a mouse.
- This stimulates the production of B plasma cells specific to this antigen.
- These B plasma cells are extracted from the mouse, and fused with a myeloma to form a hybridoma.
- The antibodies produced are extracted and purified.
From fossils, what two pieces of evidence could suggest the fossils are from the same species?
There are relatively few differences between different fossils of the same structures and structures appear to fit together for all fossils
Why are ancestral domestic and farm animals very different to modern animals?
Selective breeding has resulted in the increased frequency of traits that humans find desirable
Trace fossil and an example
Geological records of the activities of an organism rather than the organism itself, such as footprints
Cast
A mold that has filled with sediment
Mold
An impression of an organism
Primate example and hominoid example respectively
Monkey and orangutan
How do cave drawings give evidence of cultural evolution?
Passing of information between generations and evidence of complex thought or symbolic representation
Why might populations have similar genetic material?
They may have a relatively recent common ancestor or interbreeding/gene flow may occur
When is the gene pool altered?
ONLY when a new allele is introduced or an existing allele is lost
3 Advantages of bipedalism
Hands are free for manipulating objects such as tools, increased ability to travel long distances to hunt, and greater vision of predators
Trends as human ancestors become more similar to modern humans
Bipedalism (involving the centralised position of the foramen magnum,
curvature of the spinal column and more bowl shaped pelvis), larger brain size (cranial capacity), increase in leg-to-arm length ratio and longer feet with more defined arches.
Divergent evolution
When species sharing a common ancestor become more distinct due to different selection pressures
Convergent evolution
The process whereby distantly related species independently evolve similar traits to adapt to similar selection pressures
Speciation
The process by which a species evolves to give rise to at least one new species
