Inheritance & Environment Flashcards
What can cause chromosomal alteration?
Environmental factors such as radiation or other chemical triggers or randomly
What is deletion? ( chromosomal alteration)
When one gene is completely deleted/ eliminated
What is duplication? (Chromosomal alteration)
A gene is duplicated in the chromosome
What is inversion? (Chromosomal alteration)
Genes a inverted into opposite sequence
What is reciprocal translocation? (Chromosomal alteration)
Gene inter changed between homologous & non-homologous chromosome
What on the 4 kinds of chromosomal alteration?
Deletion, duplication, inversion & reciprocal transaction
When do mutations typically occur?
During gene expression, transcription, replication or translation
What is a Missense mutation?
When one amino acid is replaced with a different amino acid due to a Singh nucleotide substitution which alters genetic code
What is a nonsense mutation?
Single nucleotide replacement creating a stop codon too early
What is a frame shift mutation?
Deletion/insertion of a nucleotide causing the reading frame to shift, the most severe
What is a silent mutation?
Whe one nucleotide is replaced but it does not change the amino acid which is coded for
Are mutations selective or random?
Random
When do mutations occur?
All the time
Why does high mutation rate increase survival rate of a species?
Creates less homozygous & thus increases the chances of off spitting laving the new necessary variation of genes. Increases gene variation, diversesifices
Who was the first philosophers that started talking about evolutionary theories? A what was his theory ? (Now out dated )
Plato, typological thinking: every organism was an example of a perfect essence created by God & organisms where changing, focused on studying the perfect essence
What is typological thinking?
Platos theory that species are unchanging & variations are unimportant/ misleading
What evolutionary theory did Aristotle develope?
The scale of nature
What does the scale of nature theories about evolution?
Species are fixed types of organisms that were organized into sequence based on increased size a complexity (on a latter).
When was Aristotles theory & thinking dominant until?
1700 ‘s
What was Lamarck’s evolutionary theory?
Organisms were changing through time because of inheritance of acquired characteristics
Who introduced the idea of inheritance of acquired characteristics?
Lamarck
What did Lamarck believe happened to life experience?
He believed it was passed on to off spring
What is Darwins evolutionary theory called? & how many postulates?
Natural selection,4
What do the 4 postulates state?
- Individual organisms vary in traits they possess
- Some trait differences are heritable
- Survival and reproductive success are highly variable
- individuals with certain heritable traits are more likely to survive / reproduce
When does natural selection occur?
When individuals with certain heritable traits produce more surviving offspring than individuals without those traits therefor a frequency of the selected trait increases from one generation to the next
What is the outcome in natural selection?
A change in allele frequencies in a population over time
Does evolution happen to individuals?
No, population
Definition of natural selection
Increases frequency of certain alleles, alleles that increase fitness in specific environment
What is an example of artificial selection?
Genetically modified food products
Definition of genetic drift
Allele frequencies change randomly
Definition of gene flow
New individuals introduce new alleles to the population (ex wolfs from Europe bling mixed with wages from America).
What 2 things cause genetic drift?
- Founder effect
- Genetic bottle neck
What is the founder effect? (genetic drift)
A change in allele frequency that occurs when a new population is established
What is the genetic bottleneck? (genetic drift)
In the same environment when a major part of genetic pool / organisms are killed off
What are the 4 types of modes of selection? What are they & do they increase or reduce genetic variation?
1 stabilizing selection: favours phenotypes at the middle of the range, maintains average phenotype, genetic variation is reduced
2 directional selection: favors one extreme phenotype causing the average to change is 1 direction, reduces genetic variation
3 disruptive: favors extreme phenotypes at both ends so the average is killed off & 2 extremes survives, genetic variation increases
4 balancing selection: no change except further is crease in average, no phenotype is favoured, genetic variation is maintained
What is inbreeding? & why is it bad for survival of spices?
Mating within a family, little to no variation in alleles
What is assertive mating?
Non-random mating with respect to specific traits
What is sexual selection?
Individuals differ in a ability to attract mates
Definition of species
Evolutionary independent population, reproductive isolated population (can not breed with other species)
What is pre-zygotic isolation?
When 2 species can’t reproduce because they can’t form a zygote
What is post zygotic isolation?
When the off spring of the 2 different species can’t reproduce or survive
What are the 2 mechanisms of speciation?
Allopathic speciation & sympatric speciation
What is allopathic speciation?
Speciation that begin with physical isolation, vicariance (physical isolation like river splitting land,new environment) or dispersal (like lake stopping to freeze so wolfs can’t leave island)
What is symmetric speciation?
Speciation that occurs through populations that live within the same geographical location. Can occur through external or internal events
What does endosymbiotic theory state?
That mitochondria & chloroplast were originally free floating prokaryotes
What is mitochondria DNA passed on by?
Maternal gamete
Where does mitochondria come from?
Aerobic bacteria
Where does chloroplast come from?
Cyano bacteria
What is divergent evolution?
2 or more species come from a common ancestor
What is convergent evolution?
2 Or more species share traits that are not sourced from a common ancestor (traits come due to fitness not inheritance)
What is speciation?
Creation of a new species
What is a common critique of evolution & why is it a bad critique?
It’s “just a theory”, it’s bad because in science a theory is a thouroughly tested explanation for a group of observations made
Misconceptions about evolution
Evolution explains our origin, individuals evolve, evolution happens on purpose
What are homologous structures?
Structures that are similar due to inheritance from a common ancestor
What are vestigial structures?
Inherited structures that serve no purpose like wings in a bird that doesn’t fly
What is some evidence for evolution?
Homologous structures, shared genes (humans & chimps share roughly 99%), fossils, biogeography, direct observation (bacteria adapting to antibiotics)
What is biogeography?
The fact that populations are fitted to their environments specifically
What are the 3 types of mutations?
Gene mutations
Chromosome mutations
Genomic mutations
2 types of gene mutations
Point mutations
Frameshift mutations
4 kinds of chromosomal mutations
Deletions
Duplications
Inversions
Translocation
Types of genomic mutations (2)
Aneuploidy
Polyploidy
Where do gene mutations happen?
DNA, so can happen in nucleus, mitochondria, chloroplast, nucleoid, plasmids, viral genomes
What does gene mutation change?
DNA, thus RNA is changed & the protein is changed
What are spontaneous causes of mutation due to? Examples
Internal factors such as:
DNA replication errors: DNA polymerase errors
DNA repair errors: repair mechanises are not always 100% accurate
Mitosis / meiosis errors (chromosomal & genomic mutations)
Spontaneous chemical changes
What are induced causes of mutation due to? Examples
External factors (called mutagens)
Chemicals
Radiation
Pathogens
What are the 3 stop codons?
UAg
Uaa
UGa
What is changed is point mutation?
One nucleotide base
4 types of point mutations
Substitution
Insertion
Deletion
Stop codon suppression
What is stop codon suppression?
Nucleotide is changed so stop codon now codes for an amino acid
Result of missense mutation?
Single amino acid is changed thus protein structure is changed
Results of nonsense mutation
Shorter protein
Results of stop codon suppression
Longer protein
What happens in insertion? (point mutation)
Frame is shifted change in the entire reading frame, affecting many codons
Possible results of frameshift mutations (both insertion & deletion)
Altered amino acid sequence (thus altered protein structure )
Protein truncation (shortening)
Protein lengthening
Silent ( every unlikely )
What happens in deletion? (point mutation)
Frame is shifted change in the entire reading frame, affecting many codons
What is a somatic cell?
Any cell that is not a germ cell, the mitotic cells a non dividing cells
Example of somatic cells
Neurons, blood cells, kidney cells, bone cells ect
What are germ cells?
Gamete precursor cells, meiotic cells, can also undergo mitosis at certain stages in their life
What are germline mutations?
Mutations in gen cols
Implication of germline mutation
Will be passed on to off spring
Are somatic mutation heritable?
No
What is mosaicism?
2 or more genetically distinct cell lines
Normal humans have the same genes in all cells but in mosaicism where certain cells have a mutation in their genes. Samples from one tissue might not detect it
Can effect both somatic & germane cells
What is Lamarckism?
Theory of evolution based on the principle that physical changes during their lifetime could be transmitted to their offspring
