Evolution Flashcards
What is evolution?
Gradual change in inherited characteristics of a population over time
How does evolution occur?
Natural selection
What is Darwin’s theory?
Evolution by natural selection
All living species evolved from a common ancestor first developed more than three billion years ago
Why was Darwin’s theory eventually accepted?
They begun to challenge the idea that God made all of Earth’s animals and plants
At the time there was insufficient evidence however since then more evidence has been found
Mechanisms of inheritance and variations were not known at the time
What was Jean-Baptiste Lamarck’s theory?
That changes that occur during a lifetime can be passed on to offspring
What evidence do we have of evolution?
Fossil record
Evolution of antibiotic resistance in bacteria
What is natural selection?
Organism’s within a species show a wide range of variation in phenotype
Individuals with characteristics most suited to the environment are more likely to survive
These traits are then passed on to the offspring
What is speciation?
Speciation is the gradual formation of a new species as a result of evolution
What is the process of speciation?
1. Two populations of one species are isolated
2. Natural selection occurs so that the better-adapted individuals reproduce and pass on new traits
3. Populations have an increasing number of genetic mutations as they adapt to their environments
4. Eventually the 2 populations have adapted so much that they cannot breed to produce a fertile offspring
What factors contribute to extinction?
-New predators
-New diseases
-Increased competition for
resources
-Catastrophic events
-Changes to environment
Benefits of fossil record
Can tell scientists how individual species have evolved over time
Help us understand Earth’s history
To track movements of species or its ancestors across the world
Problems with fossil record
Many early organisms were soft bodied so they decayed before producing fossils
There are gaps in the fossil record as some have been destroyed by geological and human activity
When did Darwin publish his theory on Evolution?
1859
Who developed the system to classify living things in to groups?
Carl Linnaeus
CLASSIFCIATION OR LIVING ORGANISMS
Kingdom
Phylum
Class
Order
Family
Genus
Species