Chapter 4 Flashcards
How does Sexual Reproduction work
Allows for genetic information from two parents to be shared in their offspring (exactly 50% mother and 50% father)
Define mutations
Change in genetic information caused by a problem in DNA replication or because of an environmental factor
Define mutagens and give 3 examples
Substances that cause mutations
- Cigarettes
- Radiation
- UV light
What are the two types of mutations
Disadvantageous mutations
Advantageous mutations
Define Disadvantageous mutations and give an example
Mutations that decrease an individual’s ability to reproduce because they may affect survival
Sickle-cell anemia - a genetic disease in which blood cells mutate to look like a sickle which can cause anemia
Define Advantageous mutations and give 3 examples
Mutations that give an individual an advantage to reproduce over an individual who doesn’t have the mutation
- Horseflies resistant to DDT
- California ground squirrels that can combat snake venom
- Certain humans who are resistant to HIV
Define selective pressure and give 4 examples
Environmental conditions that select for certain characteristics of individuals and select against others
- Drought
- Famine
- Weather
- Competition for food, space, and mates
What are the two ways in which variation occurs
Sexual reproduction
Mutations
Define natural selection
A process that results when the characteristics of a population of organisms change because individuals with certain inherited traits survive specific local environmental conditions and through reproduction, pass on their traits to their offspring.
Those who pass on their traits are said to have the highest fitness.
Give an example of natural selection and describe it
Peppered moths:
The environment determines who lives and who dies. In a dark environment black peppered moths will live and white ones will get eaten while in a light environment white peppered moths will live and the black ones will get eaten.
What are the 3 human impacts on natural selection and give an example for each
Loss of genetic diversity - farmers practicing monoculture
Artificial selection - super-bull
overuse of antibiotics - leads to antibiotic-resistant bacteria
Explain adaptation
Organisms must adapt to their changing environment or they will die
Adaptations are a result of gradual changes in members of a population over time
What are the 3 types of adaptations
Structural adaptations
Behavioural adaptations
Physiological adaptations
Define structural adaptations
Physical features of an organism
Define behavioural adaptations
Inherited behaviour and/or learned behaviour of an organism
Define physiological adaptations
Internal features that permit the organism to perform special functions
Define heritable
Can pass on to offspring
Define speciation and give an example
The formation of a new species
Ex. Darwin’s finches
Define adaptive radiation
The diversification of a group of organisms into forms filling different ecological niches
ie. when a species develops into a few different species
Define niche
A position or role taken by a kind of organism in it’s community
Under what circumstance does speciation occur
Only occurs if organisms are reproductively isolated from each other. If they can’t mate, then over time a new species will form.
What are the two causes of speciation
Geographical Barriers
Biological Barriers
What are the two types of biological barriers:
Pre-zygotic and post-zygotic
Define pre-zygotic barrier
Something that prevents mating or fertilization if mating occurs
Define post-zygotic barrier
Prevent hybrid offspring from developing into a viable, fertile adult
What proves how continents are moving apart and there used to be a supercontinent called Pangea
Certain fossils and animals can be found on separate continents and therefore must have been in close proximity with each other at some point
Explain chronometric dating
Uses radioisotopes to produce dates for when a specimen is formed
Define half-life
How long does it take for 50% of radioactive substance to decay into a different element
How does carbon dating work
Can use the different types of carbon to date different sources
What is the order number of fossil records
First - amphibians
Next - reptiles
Last - mammals and birds
Define transitional fossils
Fossils that show links between groups of organisms
Define homologous structures
Organisms Have similar structural elements and origin but may have different functions
Define analogous structures
Body parts that perform similar functions even though organisms do not have common evolutionary origin
Define vestigial structures
Have no apparent function, but resemble structures their ancestors possessed
How can we trace human ancestry and where can we trace it too
mitochondrial DNA is inherited from your mother because the egg is much larger than the sperm and this can be traced to Africa
How do we compare the DNA of animals
Find the letters that are exactly the same on the same row and count the bases (most DNA bases are similar)
Define hybrid
Mixed animal that’s viable
Define viable
Alive
Define fertile
Can produce offspring
Define transformation and give an example
New species gradually develops and replaced the old species as a result of mutation and adaption to changing environmental conditions
The mammoth
Define divergence
One or more species arise from a parent species that continues to exist
Define gradualism
Gradual accumulation of small changes over a long time
Define punctuated equilibrium
Rapid bursts of change mixed with long periods of little to no change
Most evolution happens (slow/fast) but the one exception is with _______ that happen (slow/fast)
Slow, plants, fast
What are the two types of evolution
Divergent and convergent
Define divergent evolution
When two species share the same ancestral origins but have evolved differently
Define convergent evolution
Process whereby organisms not closely related independently evolve similar traits as a result of having to adapt to similar environments or ecological niches
Define extinction
The end of an organism or group of organisms (usually a species)
