| Evolution |
Process by which modern organisms have descended form ancient organisms. |
- Charles Darwin contributed most to Evolution
- HMS Beagle travelled many places,many different species
- found different places had more or less flora/fuana
- based ideas on Lyell, Lamarck et al
- creationism vs evolution:
- creation by higher power relativel rescent
- evolve by animals changing
- Physical traits and behaviors adapted environment allow animals survive |
| Common Descent |
Idea that species have descended from common ancestors. |
- part of theory of evolution
- animals descend from common ancestor
- reason for homologous structures and vestigial organs
- common ancestor very long time ago (fish) |
| Adaptation |
Process that enables organisms to become better suited to their environments. |
- enable organisms to survive and reproduce
- characteristics that increases chance of survival
- ie Giraffe = long legs + neck, bats = good hearing + echo location
- these characteristics more likely to pass on to next generation
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| Fossil |
Preserved remains or evidence of an ancient organism. |
- proved Earth was very old
- proof of evolution
- age of fossils found by relative dating and radiometric dating
- different types: cast, mold |
| Relative Dating |
Technique used to determine the age of fossils by comparing them with other fossils in different layers of rock. |
- used with geologic time scale
- does not determine actual age of fossils |
| Half-life |
Length of time required for half of the radioactive atoms in a sample to decay. |
- used to figure out age of fossils
- Uranium 238 = Lead 206 Parassium 40 = Argon 40
Carbon 14 = Nitrogen 14
- ratios: 1:1 = 1 half-life, 1:3 = 2 half-lifes, 1:7 = 3 half-lifes, 1:15 = 4 half-lifes, 1:31 = 5 half-lifes |
| Radioactive Dating |
Method of measuring rates of decay of radioactive materials to determine how long ago an event occurred or an organism lived. |
- using knowledge of different parent and daughter ratios and substances (see half-life)
- times half-life by known length of half-life to find age of fossil |
| Era |
Largest interval of time in a geologic time scale. |
- Cenozoic, Mesozoic, Palezoic, Precambrian |
| Period |
Interval in a geologic time scale that is composed of epochs. |
- (Cenozoic) Quaternary, tertiary,
- (Mesozoic) Cretaceous, Jurassic, Triassic
- (Paleozoic) Permian, Carboniferous, Devonian, Silurian, Ordovician, Cambrian |
| Epoch |
Interval of time in a geologic time scale. |
- (Quaternary) Recent, Pleistocene
- (Tertiary) Pilocene, Miocene, Oligocene, Eocene, Paleocene |
| Embryo |
An organism at an early stage of development. |
- different animals look very similar to other species
- show that similar genes are at work
- similar early development suggests common ancestors
- look similar because mutations that early kill the animal
- later in development differ from less harmful mutations |
| Homologous Structures |
Parts of different organisms, often quite dissimilar, that developed from the same ancestral body parts. |
- shows proof for common descent/evolution
- similar because developed from similar cells in embryos
- suited to particular task due to adaptation
- see also vestigial organ |
| Vestigial Organs |
Structure that serves no useful purpose or function in an organism. |
- shows proof for common descent/evolution
- organs eventually become smaller as they are no longer needed
- humans have tonsils, ear muscles (in most people vestigial), appendixes
- appendix used in koalas and other animals that eat mainly vegetation
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