B2 Flashcards
Evolution
Process by which populations of living things change over a series of generation
Does not refer to individual change
Organisms that are best adapted to their environment will be most likely to survive
Changing Earth - Fossils
Fossil Formation
- Teeth, shells, bones resist weather for a long period of time
- Insects may be trapped in amber
- Impressions left by plants/animals
- Fecal matter
- Intracellular spaces of skeletal material can be replaced with minerals
Changing Earth - Fossils
The complexity of living organisms has _____ from the past to now
Increased
Changing Earth - Fossils`
Living species are usually located in the ___ geographic region as their most closely matching fossil
Same
Dating the past
Charles Lyell (1797 - 1875)
Stated that most geological change was slow and gradual and had been going on over long periods of time
Dating the past
Relative Dating
545 - 525 MYA
* Deeper sedimentary rock layers means they formed earlier → older fossil
Dating the past
Rediation Dating
Technique to determine age of a rock or fossil by radioactive isotope decay rate
Burgess Shale
- Contains the best animal fossils
- One of the most diverse and well -reserved fossil localities in the world
During this period, life was restricted to the world’s oceans
Cambrain Explosion
Evolutionary burst of animal origins
545 - 525 MYA
Changing Earth - Biogeography
Biogeography
The study of the variation and geographic distribution of life on Earth (past and present)
Theory of Plate Tectonics
- 225 MYA Earth had 1 landmass (Pangea)
- Seperated into continents by shfiting tectonic plates
- Fossil of species older than 150 MYA were on the same continents
- Species younger than 150 MYA were on seperate continents
- They evolved after the breakup of Pangea
Homologous Structures
- Features with similar structures but different functions
- Similar origin but different uses in different species
- Forelimbs adapted for different functions, but have similar bone structure
Analogous Structures
- Similar in function and appearance but not in origin
Convergent Evolution
- Development of similar adaptations from unrelated species
- Occupy equivalent niches on different continents
- Due to similar environmental conditions
Embryonic Development
- Late 1800’s: Scientists noted similarity between embryos of different species
- Many structures in an embryo are similar to those found in common ancestors
Vestigal Features
- Rudimentary structures with no useful function
- May have been functional in ancestor
- Present in all species → very compelling evidence for evolution
All organisms share similar _____ molecules and some ____
DNA , proteins
Gene
A segment of DNA that performs a specific functions