Chapter 16 & 17 vocab Flashcards
evolution
The process of change over time
What does Darwin’s theory of evolution explain?
How modern organisms evolved over long periods of time through descent from common ancestors
What are the three patterns of biodiversity that Darwin noted?
- species vary globally
- species vary locally
- species vary over time
What did Hutton and Lyell discover?
- The earth is very old
- because of erosion the earth is old, and you can count the years of age by looking at layers
What was Lamarck’s correct idea?
Living things can change over time, and there is a link between an organism’s environment and its body structures
What was Lamarck’s INCORRECT idea and what is it called?
Inheritance of acquired characteristics: Living things can pass on characteristics they get during their lifetimes to their babies
What was Malthus’s view of population growth?
Malthus reasoned that if the human population grew unchecked, there wouldn’t be enough living space and food for everyone
What is artificial selection?
Nature provides the variations, and humans select those they find useful
What is adaptation?
Any heritable characteristic that increases an organism’s ability to survive and reproduce in its environment
What is fitness?
An organism’s ability to survive and reproduce in its environment
What is natural selection?
The process which organisms with variations most suited to their local environment survive and leave more offspring
When does natural selection occur?
- when more individuals are born than can survive
- there is natural heritable variation
- there is variable fitness among individuals
What is biogeography?
the study of where organisms live now and where they and their ancestors lived in the past
What are homologous structures?
Structures that are shared by related species and that have been inherited from a common ancestor
What are analogous structures?
Body parts that share common function, but not structure
What are vestigial structures?
inherited structures from ancestors but have lost much or all of their original function due to different selection pressures acting on the descendant
What is a gene pool?
All the genes, including all the different alleles for each gene, that are present during a population
What is allele frequency?
the number of times an allele occurs in a gene pool
What is a single-gene trait?
A trait controlled by only one gene (ex. black fur vs white fur)
What are polygenic traits?
A gene that has two or more alleles (ex human hair colour)
What is directional selection?
Individuals at one end of the curve have higher fitness than individuals in the middle or at the other end
What is stabilizing selection?
Individuals near the centre of the curve have higher fitness than individuals at either end
What is disruptive selection?
Individuals at the outer ends of the curve have higher fitness than individuals near the middle of the curve
What is genetic drift?
A random change in allele frequency
