C8 - Evolution Flashcards
What are mutagens?
Physical or chemical agents that can induce mutations in DNA
What are some examples of positive changes mutations can cause?
Creating new versions of proteins that help and individual better adapt to their environment
How can a mutation be negative?
Can cause genetic disorders
What are most genetic mutations?
Neutral, in that they don’t create any observable change
What is binomial nomenclature?
The method of naming species, created by Carl Linneaus (in 1707) and founded modern taxonomy
What does Genus mean?
General
What does species mean?
Specific, and can create viable offspring with each other
What is taxonomy?
Used to determine evolutionary relationships between organisms
What was Lamarck’s 1801 theory of evolution
Use it or lose it mentality, with portions of animal that are not used within their lifetime becoming smaller or disappearing, and parts that are more heavily used becoming larger.
What is an example that ‘proved’ Lamarck’s theory?
The giraffe, who stretched it’s neck to reach leaves, resulting in a longer neck that was passed on to offspring
Problems with Lamarck’s theory of evolution
We now know that traits acquired over an individual’s lifetime (i.e. muscles) cannot be passed onto offspring
When did Darwin publish “Origins of Species”?
1859
What were the two main ideas of Darwin’s theory?
Species are not created in their present form, but evolved from an ancestral species, and Natural selection as a mechanism for evolution
What are Darwin’s 5 points?
1: Population has variations
2: some variations are favourable
3: More offspring are produced than survive
4: Those that survive have favourable traits
5: A population will change over time
What is the evidence for evolution?
Fossils, correlation between rock and fossil age, biogeography, comparative anatomy
What are homologous structures?
Similar in structure and development but may have different features (wing of a bird and flipper of a whale), imply a common ancestor
What are analogous structures?
Similar function but no structural relationship (wing of a bird and an insect - same function - flight, but no structural relationship) - implies these two groups have different ancestral origins
What are vestigial organs?
Once used in an animals evolutionary past, but not anymore, like the pelvis on a whale
What is comparative embryology?
Comparing embryos to see similarities
What are some limitations to fossils?
Many gaps in fossil record and the chance of an organism being fossilized is very low
What are index fossils?
A plant or animal that lived for a relatively short time but was widespread, indicating it was the ‘fittest’ at the time
How are fossils evidence for evolution?
The older the rock, the older the fossil, and there are a variety of fossils in each layer of rock - fossils are different to those in upper and lower levels of rock, giving them a certain age
What is biogeography?
Patterns in species distribution, shows geographical fragmentation of ancestral species, along with continental drift and consequential isolation of populations
What is comparative anatomy?
Study of similarities and differences in anatomy of organisms - main concept is homologous and analogous structures
What is convergent evolution?
structures with different origins have evolved the same function (bird and insect)
What is parallel evolution?
Related species form similar features independently
What is natural selection?
Individuals with favourable traits are selected and are more likely to thrive and produce more offspring, passing down the trait in DNA to future generations
What is variation?
Natural differences in populations caused by genes
What is speciation?
When one species splits into two or more separate species - why there is biodiversity on earth
What are the three steps to speciation?
1: variation
2: Isolation
3: Selection
What is isolation?
Required for a new species to form (Grand Canyon Squirrel)
What are the five types of isolation?
Physical isolation (barrier - earthquake etc)
Temporal isolation (breeding at different times to other groups inside species)
Behavioural isolation (change in courtship rituals)
Mechanical isolation (incompatibility of a physical nature)
Developmental isolation (after copulation - offspring is not viable)
What is the gene pool?
All the alleles that exist in a population
What is allele frequency?
How common the allele is within the population
What is gene flow?
Movement of genes from one population to another - due to migration
What is genetic drift?
Variation in the relative frequency of genotypes in a population - due to random sampling
What is microevolution?
Survival through inheritance of favourable genes (traits) - results in changes within a population
What is macroevolution
Progression of biodiversity of geological time and results in new species, caused by speciation/extinction
