Old and New species
- Created by: Moodymoo
- Created on: 09-02-14 13:51
View mindmap
- Old and New Species
- Fossils
- Fossils are the remains of organisms from many years ago
- Formed from hard parts of an animal, e.g. bones
- When an animal/ plant doesn't decay after it dies due to a lack of a condition needed for decay, e.g. low temperature
- Formed when harder parts of animal/plant are replaced by minerals, most common fossils
- Traces animals/plants leave behind, e.g. footprints, droppings
- Incomplete Record
- Many of the earliest forms of life were soft-bodied organisms, so have little fossil trace
- Partly why there is little valid evidence why earth began
- Many of the earliest forms of life were soft-bodied organisms, so have little fossil trace
- Using the Fossil Record
- Helps us understand how much fossils have changed
- However, only bits of skeleton have been found
- They show us that not all animals have changed very much, e.g. sharks
- Extinction
- The permanent loss of a species
- As conditions change, new species that are better suited to the environment survive
- Old species cant cope with the new conditions die out
- Organisms that cause Extinction
- New predators can wipe out unsuspecting prey quickly
- New diseases (caused by microorganisms) cause it
- Through successful competition, e.g. competing for food
- Environmental Changes
- Climate and environment on Earth has changed
- Many species become extinct through lack of food or being too cold to breed
- Mass extinctions, most species die out
- Isolation and Evolution
- Populations become isolated when they are separated geographically e.g. on islands
- The species might change so much that they can no longer interbreed
- Speciation
- Populations contain genetic variety, so contains a lot of alleles controlling characteristics
- When two populations can no longer interbreed, become two different species
- Populations become isolated when they are separated geographically e.g. on islands
- Fossils
Comments
No comments have yet been made