Evolution Flashcards
(34 cards)
What is evolution?
The gradual change of organisms over time
What are three examples of evidence of evolution from living things?
- Anatomical Similarities
- Embryological Similarities
- Biochemical Similarities
What is a fossil? Where are they found?
A trace or remain of an organism preserved by natural processes. Usually found in sedimentary rock
What does comparative anatomy study?
Structural similarities and differences among living things.
What is a homologous structure? Why is it important?
Parts of different organisms that have similar structure and development. This is evidence that some species evolved from a common ancestor.
What is an analogous structure?
Structures that have similar external features but different internally, like wings on both birds and bugs.
NOT EVIDENCE of a common ancestor.
What is a vestigial structure?
Remnant of structures that were functional in an ancestor, but in modern organisms are reduced in size and don’t really have a function.
Why are embryological similarities important?
Embryos of closely related species show similar patterns of development.
Ex: Early development of fish, turtles, pigs, and humans are similar, indicating a common ancestor
The more closely related the species, the more they resemble each other during development
What are biochemical similarities?
The closer the evolutionary relationship between the two species, the more alike their DNA and their proteins will be.
Ex. Amino acids in hemoglobin of closely related species are nearly identical
What was Jean Baptiste de Lamarck’s theory of evolution?
- The law of Use and Disuse - the more an animal uses a part of the body, the stronger and better developed it is, and the less it is used the weaker it gets
- The inheritance of acquired characteristics - characteristics that an individual develops through use and disuse could be passed on to offspring
What was Jean Baptiste de Lamarck’s theory about giraffes’ necks?
Their ancestors had short necks and fed on grass. Food supply decreased, and giraffes had to stretch their necks to reach food higher up, so their necks became longer, and this trait was passed on to their offspring, and over time the giraffes neck became longer and longer
What did August Weismann think about Lamarck’s theory of evolution?
He disproved it - he cut the tails off of mice for 22 generations, but in the next generation the mice were always born with tails
What are the six parts of Charles Darwin’s theory of evolution?
Overproduction Competition Variation Adaptations Natural Selection Speciation
What does OVERPRODUCTION mean in Darwin’s theory of evolution?
most species produce more offspring than needed
What does COMPETITION mean in Darwin’s theory of evolution?
living space and food are limited, so offspring have to compete for survival
What does VARIATION mean in Darwin’s theory of evolution?
Characteristics of individuals of a species may differ in certain traits
Some may be unimportant, but others may affect an individual’s ability to get food, escape enemies, or find mates
What does are ADAPTATIONS in Darwin’s theory of evolution?
Any variation that improves an individual’s chance of survival
The individual with the most favorable adaptations will have highest chance of surviving and reproducing
What does NATURAL SELECTION mean?
based on the environment, the individuals with the most favorable adaptations reproduce and pass these traits to their offspring
What is SPECIATION in Darwin’s theory of evolution?
favorable adaptations accumulate in the species, and unfavorable ones disappear. Eventually the changes are so great that the result is a new species
How did giraffes get their long necks, according to Darwin?
Although most giraffes had short necks, variations existed among the population and there were some with long necks. When grace was scarce, the long necked ones survived because they were able to obtain food. Their offspring then inherited the long neck trait
What does the theory of GRADUALISM describe?
That evolution occurs slowly and continuously over millions of years
This is Darwin’s theory
What is punctuated equilibrium?
A species stays the same for extended periods of time, and then in a short period of time there is rapid evolution.
The fossil record supports this because there are transitional forms missing
What is Industrial Melanism? (Moths, industry.) How did this happen because of natural selection?
Before industrial revolution, had mostly light moths; dark moths were rare. Then, the industrial revolution meant that heavy smoke darkened the trees and within 40 years, 99% of moths were dark. Still had light moths in nonindustrial areas
Natural Selection: the ones that could blend in weren’t eaten
What did Esther and Joshua Lederberg find about bacterial resistance to antibiotics?
That resistance happened once antibiotics started being used more often because of natural selection.
They did an experiment with E. coli, and found that over time, if there was a bacterium that started out immune, by the end they covered the Petri dish - selecting for bacterial colonies that already were resistant
