Topic 3 Flashcards
What did people think of species before Darwin?
People noted that fossils usually didn’t look like living animals so they assumed that extinction must have occurred. The reasons for this varied such as supernatural, natural disasters, one species slowly changing into another and that things weren’t extinct just hiding
What did Curvier think?
Species did not change over time but instead strata were due to catastrophes that caused extinction and new species would populate
What did Lamarck think?
Species changed over time due to: Inheritance of acquired characteristics (a characteristic acquired during an organisms lifetime could be passed to its offspring)
What did Darwin believe?
He believed in evolution by natural selection and decent with modification
What is descent with modification?
The passing of traits from parent organisms to their offspring
What were Darwin’s 3 inferences?
- Organisms must compete for limited resources and not all succeed. 2. Some heritable variations are likely to provide individuals with a competitive advantage. 3. Individuals with advantageous variations are likely to leave more offspring then others
Do Individuals evolve?
Populations evolve not individuals
What is context dependency in Natural Selection?
There is not innate tendency for perfection, instead species evolve based on their context
What is phenotypic variation?
Form, function and behavior
What is genotypic variation?
Genetic make-up
How does Natural Selection act on variation?
It must be expressed phenotypically and genotypically
What are the sources for variation?
Mutation, Recombination, Independent assortment of chromosomes and fertilization
What is a Slecetive Agent? What types are there?
A selective agent is a component of the natural environment that consistently causes differential survival or reproduction. The examples are biotic-living and abiotic-non-living
What is the evidence for evolution?
Fossil Record, Homology, Direct Observations and Biogeography
How does the fossil record support evolution?
Strata can be used to date fossils. In a strata forms are consistent. Intermediate forms can be identified that appear to be ancestors of current species. Extinction is seen in the record
What is homology? How does it support evolution?
Similarity due to common ancestry. We can see this in comparative embryology evidence, vestigial structures and in molecular evidence
What are transitional links?
The intermediate fossils that seem to be ancestors of current species
How do vestigial structures support evolution?
Certain species have structures in their body that they do not need but can link them to common ancestors. Such as leg like structures in whales
How does embryology support evolution?
When in the embryonic stage many species look very similar and have similar structures. This contributes to the idea that they share a common ancestor
What is molecular evidence?
The universal genetic code is: DNA-amino acids-proteins
What is direct observation?
The use of artificial selection, antibiotic resistance and the development of pesticide resistance are examples of direct observations
What is artificial selection?
Selectively breeding organisms in order to gain a desired trait. It shows that evolution can be forced onto a species
How does antibiotic resistance support evolution?
Bacteria show that they can evolve to no longer be effected by antibiotics
How does development of pesticide resistance support evolution?
This shows that after all the pest that are not effected by pesticides are the only one to produce offspring for the next generating meaning the next generation is completely resistant to pesticides; they have evolved
What is Biogeography?
Regions with “identical” climates have different species yet show convergence of form and function
