Variation, evolution and classification Flashcards
- Variation and evolution - Classification
Adaptation
An adaptation is a characteristic that helps an organism to survive and reproduce.
Evolution
Evolution is the gradual change in the characteristics of a population from one generation to the next. The theory of evolution is that all organisms evolved from simple life forms over millions of years.
What is an adaption?
Any characteristic of an organism that increases its chance of survival.
What does variation lead to?
Natural selection
What is an allele?
An alternative version of a gene
Briefly describe natural selection.
Organisms with good adaptations are more likely to survive and reproduce, and so pass on the alleles for those good adaptations.
What is classification?
Classification means sorting organisms into groups and naming the organisms.
Why do we use classification?
It makes it easier for scientists to study organisms without getting confused.
How are organisms arranged?
Organisms are arranged into groups depending on their similarities and differences
What is a species?
A species is a group of organisms that look similar and can reproduce to give fertile offspring.
What are classification systems based on?
1) Older classification systems grouped organisms based only on how they look, e.g. four limbs, six eyes…
2) Newer systems use looks and lots of other things
- DNA: how similar and different the base sequence is
- Other molecules: e.g. proteins and enzymes
- Early development: how they grow from an embryo to a baby.
What does classification involve?
Sorting organisms into groups (based on their similarities and differences) and naming them.
What is a species?
A group of organisms that look similar and can give fertile offspring.
List four things new classification systems use to group organisms.
How they look, DNA, other molecules and early development.
