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