Evolution Flashcards
How old is the earth?
The earth is 4.5 billion years old
How long ago did the first prokaryotes emerge?
The first prokaryotes emerged 3.8 billion years ago
How long ago did the first eukaryotes emerge?
The first eukaryotes emerged 2.7 billion years ago
What is natural selection?
In natural selection, the traits of a species that favor survival and reproduction will leave more offspring and thus will be passed down more readily to future generations
- The best adapted individuals tend to leave more offspring
- Competition occurs due to many organisms competing for limited resources
- The number of offspring emerging in the environment tends to be more than the environment can support. (something has to die)
What is a cetacean?
A cetacean is a clade of aquatic mammals that includes whales, porpoises, and dolphins
- Their forelimbs have been reduced to flippers
- They have large amounts of myoglobin, making it very easy for them to hold their breath for a long period of time.
- They are descendants of land mammals that found a better ecological niche in the water
What were jean-baptiste Lamarck’s theories?
Lamarck had several theories. Some true and some false
- Theory of acquired characteristics: Lamarck believed that you passed on your traits gained in your life. A body builder would have muscular offspring, or a giraffe stretching its neck would pass on its long neck to its offspring: FALSE
- Use and Disuse: If you don’t use it, your body will lose it. Muscles atrophy without use: TRUE
- Lamarck believed organisms moved toward greater complexity: FALSE
What is artificial selection?
Artificial selection is when people modify a species by giving a population desirable traits through selective breeding or genetic modifications
- Plants: Superior crops, hybrid roses, etc
- Animals: Selective breeding for meat quality, hunting dogs, etc
What are homologous structures?
Homologous structures: Structures or organs that are similar in morphology (shape), anatomy, genetics, and embryology, but have different functions. They may even look different.
- They have a common ancestor
- They include:
1) Flipper of a whale
2) Wing of a bat
3) Leg of a cat
4) Arm of a human - When the above are compared, they are homologous strutures
What are analogous structures?
Analogous structures are structures with the same function, but they evolved separately. They also have a similar appearance
- No common ancestor
- Analogous structures include:
1) Wing of a bat and wing of a bird
2) Wing of an insect and wing of a bird
3) Fish fins and whale flippers
4) jointed legs of insects and vertebrates used for locomotion
5) The spine of a cactus and thorn of a rose
What scientist first started taxonomy?
Carolus Linnaeus was the first scientist to begin taxonomy of species
- He classified species by how similar looking they were. Clearly this was an incorrect way to classify species as they may or may not have had a common ancestor
What is convergent evolution?
Convergent evolution occurs when species evolve independently to form analogous structures when exposed to a similar ecological niche or environment
- Sugar glider and flying squirrel
- No common ancestor
What is divergent evolution?
Divergent evolution occurs when we see an ancestral species form into a number of different species with both similar and different traits.
- Common ancestor
- Darwin’s Galapagos Finches
What is the best technique to determine phylogenetic relationship between species?
The best technique to determine phylogenetic relationship is DNA analysis and protein comparison
What are the scientific areas of study that support evidence of evolution?
The scientific areas of study that support evidence of evolution include:
- Taxonomy: Naming and classifying organisms
- Molecular Biology: Studies molecular structures
- Paleontology: Studies fossils
- Biogeography: Studies past and present species distribution
- Genetics: Studies genes and DNA
- Comparative anatomy: Studies different structures
What does the term “Ontogeny Recapitulates Phylogeny” mean?
It means as an organism develops, it undergoes the same successive stages as did the species in its evolutionary development
- Think tail on a human embryo
- This is essentially false
- Formulated by E.H. Haeckel
