Variation and Adaptation Flashcards
How do fossils form?
Organism dies and is buried by sediment. Sediments become cemented
together.
Describe how the age of fossils changes when found in horizontal rock layers.
In sedimentary rock layers, the oldest layer is at the bottom. Each layer is younger than the layer below it.
Who was Charles Darwin?
Darwin was a naturalist on the HMS Beagle and he studied organisms during a five year journey.
What theory did Charles Darwin form?
The theory of evolution
Where did Charles Darwin do his studies?
The Galapagos Islands
What is selective breeding?
The process of choosing organisms with the desired traits to be parents for the next generation
Give 3 examples of selective breeding.
a. Breeding sheep with soft wool so that the offspring have soft wool
b. Breeding race horses for speed and endurance
c. Breeding pigeons for large tail feathers
What is a species?
Organisms that can mate and produce fertile offspring
What does the fossil record show?
It shows how life forms have changed over time.
What adaptation did the Galapagos finches have?
Beak shape
In what type of rock are fossils usually found?
Sedimentary
What is natural selection?
The process where organisms that are better suited to the environment live longer and reproduce more than organisms less suited to the environment
Give 2 examples of natural selection.
a. Beak shape
b. Color of moths
What is overproduction?
More organisms are born than can survive
How does natural selection work?
Natural selection works on characteristics passed by genes
What factors affect natural selection?
Overproduction, competition, and variations
What is competition?
Members of a species compete with one another for limited food, shelter, mates, etc.
What are variations?
Differences between members of a species
What is an adaptation?
Any heritable trait that helps an organism, such as a plant or animal, survive and reproduce in its environment.
What is embryology?
The study of the development of embryos
Why do scientists study embryos?
They look for similarities of different organisms to see if they share a common
ancestor
What evidence can be used to infer evolutionary relationships?
Fossil record, similarities in bodies of living organisms, similarities between living organisms & fossils, similarities among embryos of different organisms, & genetic and molecular information
What is a common ancestor?
An ancestor that several organisms evolved from
How does the fossil record show evidence of change in organisms?
It shows the changes in species and the increase of biodiversity; it also shows the extinctions
What is common ancestry?
The idea that all organisms share a common ancestral species from which they evolved
What is an extinction?
When a species no longer has any living member
What is a mass extinction?
When multiple organisms go extinct at the same time
How do scientists find the cause of an extinction? What do they look at?
They analyze rock layers before, during, and after an extinction event. fossils that have body structures that are found both in ancestral species and in its descendants
What is a mass extinction?
When many species go extinct at the same time
What are vestigial structures?
An anatomical feature or behavior that no longer seems to have a purpose in the current form of the organism. Examples: appendix, goosebumps, wisdom teeth 32. What are homologous structures? A body part of one species that closely resembles that of another species. A body part similar in position, structure, and evolutionary origin, but not
necessarily in function. Example: dolphin fin, mole paw, human hand
What is a common ancestor?
The most recent individual from which two or more species descended
What is a transitional fossil?
fossils that have body structures that are found both in ancestral species and in its descendants
