Evolution Flashcards
What is the most notable form of life during each era
Cenozoic
What is thought to have caused he extinction of the dinosaurs ?
. Meteor impact with Earth created climate change at the end of the Mesozoic.
Define absolute dating
uses radioactive isotopes to find the precise age of rocks and fossils
Define relative dating
Relative dating compares two evens to see which one is older.
What is the theory of natural selection ? Who proposed it?
The process by which individuals that are better adapted to their environment survive and reproduce more successfully than less well adapted individuals do. Charles Darwin
Transitional forms
Intermediate fossils that connect older fossils with newer ones
Homologous structures
Similar structures found in different organisms. Human arm bones, bat wing, bird wing, etc.
Vestigial structures
Structures that no longer serve a viable function for the organism. Pelvis in whales, leg bones in some snakes
What is an adaptation?
A trait or characteristic that improves an organism’s chances for survival and/or reproduction.
What is evolution?
The theory that life changes to suit its environment over time and give rise to new species
What is selective breeding?
when humans select for traits in plants and animals to be passed to the next generation.
What did Darwin not understand about how natural selection works?
He didn’t understand genetics or how genes were inherited
Who was Malthus and Lyell? How did their ideas aid Darwin?
Malthus was an author of a book on the study of populations. Darwin realized that any species can produce many offspring and that there are limiting factors so that not all offspring survive. Thus, some of the offspring must have some traits that made them better survivors. Lyell was an author of the Principals of geology
What is significant about the Miller-Urey experiment ? What did it prove and didn’t prove ?
The experiment proved that life could have formed on Earth with the right conductions. It didn’t prove that is how life actually started.
What important gas needed for most animals to survive was lacking in the early atmosphere?
Oxygen
Why were Cyanobacteria so important to the formation of the modern atmosphere?
produced oxygen which could then reformed to make ozone
How was the ozone layer formed? What is its function in the atmosphere
It was formed by the oxygen produced by photosynthetic organisms like the cyanobacteria. Oxygen consisting of 2 atoms combined with single atom oxygen to form ozone. It blocks harmful UV light from the sun.
What are the four nitrogen bases?
Adenine, Thymine, cytosine, Guanine
What are the three parts of a nucleotide?
Nitrogen Base, Phosphate, Deoxyribose (Sugar)
How do the bases pair up?
A-T and C-G
Why are the bases and their order important?
It is the genetic code or the blueprints for life.
What is the shape of DNA called?
Double helix
Define dominant and recessive
A dominate trait always shows as the phenotype. Recessive only shows as the phenotype when it is in the presence of another recessive allele.
What’s the difference between a genotype and phenotype?
Genotype is what your genes are, dominant or recessive. Phenotype is the physical expression of the genes.
Define homozygous
same alleles
Define heterozygous
Different alleles
What are the four eras from earliest to most recent ?
Precambrian, Paleozoic, Mesozoic, Cenozoic
