Evolution & Common Ancestry
Evolution is the process by which species will change over time. It describes how the life on the earth evolved from the simple life to the huge variety of plants and animals and human life forms we see now. There are two major evidences of evolution in fossil records and genetic evidences important in revealing to scientist how all living things are related by a common ancestor.
1. Fossil Records
📜 Fossil Records
Fossils are the preserved remains or vestiges of ancient organisms. They show how life evolved over time.
- Show transitions between species (e.g., fish with limbs)
- Provide evidence for extinct species
- Help create evolutionary timelines
What Fossil Records Show:
Slow changes in species during periods of time.
Extinct species that are no more in the present day.
Transitional fossils that have features of two different groups (e.g. fish with limbs).
Why Fossils Matter:
They provide physical evidence of the past life.
Assist scientists in putting together family trees of evolution.
The fossil layers can be used to date the dates of rocks and the organisms in them so that their sequence of evolution is known.
2. Genetic Evidence
🧬 DNA Similarities
Genetics supports the idea of a common ancestor shared by all living things.
- Humans and chimpanzees share over 98% of DNA
- Many genes are shared across diverse species
- Although very dissimilar organisms such as humans and fruit flies have many of the same genes
Mutations and Variation:
Minor variations in the DNA (mutations) can cause new traits.
These characters could give one an edge and get transferred through natural selection.
Protein and Gene Comparisons:
Scientists compare genes and proteins to determine evolutionary relationship.
The closer the species are related the more alike the DNA are.