Chapter 16,17 Flashcards
Define evolution.
The process by which organisms have changed over time.
Define natural selection.
The mechanisms by which evolution occurs.
What happens when overproduction happens?
There will be more organisms that are born than the environment can support. This results in competition for things such as food, shelter, mates.
Define variation in a species.
Individuals of a species that are all different from one another.
Define adaption.
Any heritable characteristic that increases ability to survive/reproduce.
What happens if an individual is better suited to an environment?
It out compete the others.
Define fitness.
How well an organism survives and reproduces in its environment.
What leads to extinction?
If the environment changes and there are no heritable characteristics that allow organisms to survive.
Explain common descent.
Every organism alive today is descended, with modification, from ancestors that survive and reproduce.
How did Hutton and Lyell influence Darwin?
They stated that the Earth is very very old.
How did Lamarck influence Darwin?
He stated that:
a) living things change over time
b) there is a link between an organism’s environment and its body structure
c) living things can pass on characteristics they acquire during their lifetimes to their offspring
Which one of Lamarck’s statements are wrong?
living things can pass on characteristics they acquire during their lifetimes to their offspring.
THIS STATEMENT IS INCORRECT.
How did Malthus influence Darwin?
He stated that “increasing population size results in more competition for limited resources like food/living space.”
How did farmers influence Darwin?
They used “artificial selection”.
Farmers select only individuals with “desirable” characteristics to breed with each other. That increases that characteristic in the next generation.
Define artificial selection.
When nature provides the variations but humans select which variations get passed on.
What is the 5 evidence of evolution?
- Comparing anatomy and embryology
- Testing natural selection
- Genetics and molecular biology (Homologous molecules)
- Age of the Earth and fossils
- Biogeography
What is a homologous structure?
Organisms that share homologous structures have descended (with modification) from a common ancestor.
These structures may look different, and used differently, BUT have similar development/internal structures.
Ex. Bird’s wing and a horse’s leg.
What is an analogous structure?
Structures that are used for the same function, but don’t have similar underlying structures.
Ex. A bat’s wing and a butterfly’s wing.
What is a vestigial structure?
Remains of a structure that was once useful in an ancestor, but useless to the organism now.
Ex. Hipbones of a dolphin.
Would embryos sometimes look similar because they’re descended from a common ancestor?
Yes.
How did the Grants study evolution and natural selection?
The Grants studied the finches in the Galapagos for over 35 years. They observe changes in the average beak depth of a population in response to environmental conditions. For example, during a drought, average beak depth increased. This is evolution!
Where is cytochrome C found?
Basically in nearly all living cells.
How old is the Earth?
Approximately 4.5 billion years old.
How did scientists find out how old the Earth was?
They used radioactive dating.
Define biogeography.
The study of where organisms live now and where.
What does “closely related but different” mean?
When different environments can favour different characteristics in closely related species.
What does “distantly related but similar” mean?
When similar environments can favour similar adaptions in distantly related species.
