Biology SB4a Flashcards
What is a species?
A group of organisms that can interbreed to produce fertile offspring
What is a fossil?
fossils are remains, impressions or traces of animals, plants and other organism that lived millions of years ago
What is a fossil record?
a fossil record is the history of life as documented by fossils, the remains or imprints of organisms from earlier geological periods preserved in sedimentary rock
What does the fossil record show?
it can show how the changes in an organism were linked to changes in its habitat it can also show how different species evolved from a common ancestor
What is the definition of evolution?
the gradual change in characteristics of a species over time
How is the evolution of a species studied?
fossils are discovered put in chronological order and the changes are studied
How do scientist track common ancestors between species?
if the two organisms share similar bone structure it shows evidence of a common ancestor
Name three uses of sophisticated stone tools.
Any three:
- Hunting / killing animals
- Skinning animals
- Preparing food / cutting food
- Building shelter
- Lighting fire
Why are there gaps in the fossil record? (4)
- Soft tissues decay and does not form fossils
- The hard parts of some organisms were destroyed
- Some fossils have not been discovered yet
- Fossils are often broken into pieces
Exam question:
Using the theory of natural selection explain how giraffes evolved to have a longer neck?
- There is GENETIC variation in the population of giraffes
- Due to mutations
- Some have shorter necks and some longer by chance
- The longer necked ones could get food easier so they had a selective advantage
- They survived, reproduced and passed alleles on to the next generation
- So the population of long necked giraffes increased
- While the population with short necks could not get any food and did not survive
What is Selection pressure?
Selection pressure is a factor in nature that pressures
some individuals to survive better than others
What is selective advantage?
Selective advantage is when some individuals who have are
better adapted have an advantage in surviving
What are some common factors all vertebrates have?
Most vertebrates have limbs and their the internal bone structure is very similar e.g. all have radius, ulna, humerus
What is the pentadactyl limb structure?
5 digits
What are the 7 levels of classification? (In order)
Kingdom
phylum
class
order
family
genus
species