Ch.16-17 Test Flashcards
Who was Charles Darwin?
Scientist who fathered evolution. Developed a scientific theory of biological evolution that explains how modern organisms evolved over long periods of time
What is evolution?
Change over time; process by which modern organisms have descended from ancient organisms
Describe Darwin’s voyage.
Sailed on the HMS Beagle for 5 years and mapped the coastline of South America. Observed characteristics and habitats of different species
What are 3 distinctive patterns Darwin notices?
Species vary globally
Species vary locally
Species vary over time
Give an example of how species vary globally
Rheas and ostriches are very similar yet rheas are from South America and ostriches are from Australia
Give an example of how species vary locally
There are 2 different species of rheas living in South America. One lives in grasslands and one lived in harsh scrub land
What did Darwin look at to show that species were changing over time?
Fossils
Describe what James Hutton researched
Researched the connections between a number of geological process and geological features
Describe what Charles Lyell researched
uniformitarianism
What is “deep time”?
Concept of geologic time by Hutton; the multimillion year time frame within which scientists believe earth has existed
What is uniformitarianism?
idea that the geological processes we see in action today must be the same one that shaped Earth millions of years ago
What could have caused Darwin to find marine fossils thousands of feet in the mountains?
Formation of a mountain, dropping of sea level
Who was Lamarck?
French naturalist
What did Lamarck believe?
Believed that organisms could change during their lifetimes by selectively using or not using various parts of their bodies
Who was Thomas Malthus?
English economist
What did Malthus believe?
Humans were being born faster than people were dying, causing overcrowding
What did Malthus say acted to help reduce population number?
war, famine, and disease
What is artificial selection?
When nature provided the variation and humans select those they find useful
Why did it take Darwin so long to publish “On the Origin of Species?”
His ideas were radical and he wanted as much proof as possible before making them public
What is an adaptation?
Any heritable characteristic that increases an organism’s ability to survive and reproduce in its environment
Describe some structural adaptations.
Tiger’s claws, colors that make camouflage or mimicry
Describe some behavioral adaptations.
The way a plant carried out photosynthesis
Describe an organism that has a high level of fitness for its environment
A chameleon can blend into its environment hiding from prey and live to reproduce and pass on the camouflage trait
What is natural selection?
Process by which organisms with variations most suited to their local environment survive and leave more offspring with the same variations
What types of traits does natural selection act on?
inherited traits
How could a species become extinct?
If environmental conditions change faster than a species can adapt to those changes
What is the principle of common decent?
All species-living and extinct-are descended from ancient common ancestors
What is decent with modification?
Living things are descended with modification from common ancestors
What is biogeography?
The study of where organisms live now and where they and their ancestors lived in the past
What are the 2 biogeographic patters that are significant to Darwin’s theory?
divergent and convergent evolution
About how old is Earth?
4.5 billion years old
What are the things that Darwin pointed to as evidence for evolution?
fossil record, anatomy, embryology, genetics/molecular biology
What is a homologous structure?
structures that are similar in different species of common ancestry
Give an example of 2 homologous structures.
human arms and dog legs
What is an analogous structure?
Body parts that share a common function, but not structure
Give an example of 2 analogous structures.
Butterfly wings and bird wings
What are vestigial structures?
structure that is inherited from ancestors but has lost much or all of its original function
Give an example of a vestigial structure in a human
Appendix
What is embryology?
Branch of biology that studies the development of gametes, fertilization, and development of embryos and fetuses
How did Darwin say that embryology showed proof of evolution?
Early developmental stages of animals with backbones look very similar
How does the genetic code relate to Darwin’s theories on evolution?
All living cells use info coded in DNA and RNA to carry info from one generation to the next and to direct protein synthesis. The more closely related 2 organisms are , the more closely related their DNA, RNA, and proteins
any change in the relative frequency of alleles in the gene pool of a population over time
evolution
Natural selection acts directly on ____
phenotype
a group of individuals of the same species that mate and produce offspring
population
consist of all the genes, including all the different alleles for each gene that are present in a population
gene pool
2 sources of genetic variation
mutation genetic recombination (Crossing over)
Natural selection on _______ can lead to changes in allele frequency and thus to changes in the phenotype frequencies
single-gene traits
Natural selection on polygenic traits can affect the distribution of phenotypes in three ways:
- Directional selection
- Stabilizing selection
- Disruptive selection
