Lecture 1- evidence of evolution Flashcards
What is the importance of evolution by natural selection
Evolution by natural selection helps the organism adapt to changing environments. Creates phenotypic changes over time.
Define evolution
Evolution is defined as a change in the allele frequency in a population over time
Name the preconditions for evolution by natural selection
Three preconditions-
- Heritable characters
- genetic variation in the population
- differential fitness in reproduction and survival
Define natural selection
Natural selection is the mechanism by which evolution occurs. Natural selection occurs when a change in the environment causes certain traits/alleles to be advantageous, allowing certain individuals with those traits to survive, reproduce and pass on traits to offspring.
differentiate between evolution and natural selection
Evolution is the change in allele frequency, natural selection describes how that change takes place. NS is one out of many possible mechanisms for evolution (adaptive)
explain fossil evidence with respect to trilobites and whales
Trilobites have shown the most evolution in short periods of time (3 million years).
Whales are more closely related to hippos- proof of this - still has hip bone- proves that it moved from land to sea
Explain the significance of the discovery of Tiktaalik roseae
fish with limbs- missing link between 340 mya and 360 mya- The existence of tetrapod features in Tiktaalik marks the earliest appearance of fish having legs in the fossil record. This is the moment when the 1st ever fish ventured from sea to land.
explain vestiges
This is an anatomical structure or organ of the body that is degenerate, having become functionless in the course of evolution.
what is bad design and how is it caused
bad design is when a particular design has no function but it made sense in the ancestral design- caused by natural selection
why does natural selection tinker and not design
because it carries forward the same body design without change as the organism evolves and this design is redundant or harmful for the species, eg: laryngeal nerve
what does differential fitness mean
fitness of the organism or species to survive harsh conditions or the ability to reproduce between individuals
what are heritable characteristics
characters or traits that can be passed down from 1 generation to the other
define palaeontology
predictive science- the study of fossils
what are genotype and phenotype
genotype- unique genome
phenotype- heritable physical traits
what does allele frequency mean
incidence of a gene variant in a population
