UNIT 7 Notes Flashcards
(33 cards)
What does the Heterotroph Hypothesis propose about the first organisms?
The first organisms were anaerobic and heterotrophic bacteria that released oxygen.
This hypothesis suggests a progression from anaerobic bacteria to autotrophs and then to aerobic heterotrophs.
What are the stages of evolution according to the Heterotroph Hypothesis?
- Anaerobic heterotrophic bacteria releasing oxygen
- Evolution of autotrophs using solar energy
- Evolution of aerobic heterotrophs using oxygen released from autotrophs
This sequence illustrates the transition from simple to more complex life forms.
Define evolution.
Evolution is change in a species’ population of organisms over time.
More specifically, it refers to changes in the genetic makeup of a species over generations.
Why are mutations often considered the raw materials of evolution?
Mutations cause different phenotypes and contribute to natural variation.
This genetic variation is essential for the process of evolution.
What is required for a species to change over time?
Anecdotal mutations must occur in that species’ gene pool to create new alleles in offspring.
Mutations introduce genetic diversity which is crucial for evolution.
What processes can change DNA?
- Mutations
- Meiosis
- Fertilization
These processes can introduce genetic variation in a population.
What happens if a DNA change creates a new advantageous trait?
The offspring will have a much greater likelihood of surviving and reproducing.
This concept is a key aspect of natural selection.
Fill in the blank: Evolution is the change in a species’ population of organisms over _______.
[time].
True or False: All mutations are harmful to an organism.
False.
What is Artificial Selection?
Humans breed animals and grow plants, choosing which individuals are parents of the next generation based on desired traits.
This process has been occurring for thousands of years.
How old is the Earth?
4.5 billion years old, not 6,000.
This age indicates that Earth changes over very long periods.
What are some processes that change the landscape of the Earth?
- Volcanoes create new land
- Erosion changes the landscape
- Earthquakes and mountains also contribute to landscape changes.
These processes occur over extensive timescales.
What factors limit human population growth?
- Disease
- Conflict (war/competition for resources)
- Famine (not enough food)
These factors cause mortality and affect population dynamics.
Fill in the blank: Humans have been breeding animals and growing plants for thousands of years, a process known as _______.
Artificial Selection
True or False: The Earth has changed significantly over short periods of time.
False
Changes occur over very long periods.
What is the significance of the age of the Earth in relation to evolution?
It allows for gradual changes and evolution to occur over extensive timescales.
This understanding is fundamental to Darwin’s theory.
What is overproduction in the context of offspring?
More offspring are born than can possibly survive to reproduce themselves.
This concept highlights the potential for populations to grow exponentially if all offspring were to survive.
Give an example of organisms that can overproduce.
Bacteria, insects, dandelions, rabbits.
These examples illustrate how certain species can produce a large number of offspring, leading to potential overpopulation.
What is the role of competition in natural selection?
Individuals within a species compete for limited resources such as water, food, and mates.
This competition is crucial because it affects survival and reproduction.
What does ‘Survival of the Fittest’ mean?
The individuals who survive are those best adapted to exist in their environment.
This phrase emphasizes the importance of adaptation in the process of natural selection.
What are the differences in form that contribute to survival?
Variations that maximize survival.
These variations can include physical traits, behaviors, or other characteristics that enhance an organism’s ability to thrive in its environment.
Fill in the blank: Natural selection leads to competition for _______.
resources.
True or False: All offspring born in a population will survive to reproduce.
False.
What is a trait in the context of adaptations?
A characteristic that can change in a population to increase survival chances.
