Evolution and Natural Selection
Terms in this set (17)
Lamarck - Use and Disuse Theory
In this theory:
Lamarck thought that organisms could change the size or shape of their organs by using their bodies in new and different ways (acquired traits) these gained traits can then be passed onto offspring through reproduction
- Evolution: the process of change over time
- Natural Selection: process by which organisms that are most suited to their environment survive and reproduce most successfully; also called survival of the fittest
Are evolution and natural selection the same thing?
Natural Selection is the driving force behind Evolution (both are theories "by" Darwin)
Why was the voyage on the HMS Beagle significant to Darwin?
The HMS Beagle voyage led Darwin to develop his theories (evolution or Descent with Modification, natural selection)
Components of Natural Selection
G - Genetic Variation
O - Overproduction of Offspring
D - Differential Survival and Production
S - Struggle for Existence
How are genetic variation and reproduction the keys to natural selection?
Natural Selection occurs because of different traits and survival of the fittest (see grasshopper example above). Natural selection occurs when there are more individuals born than can survive, and this happens when there is too much reproduction or overproduction. After the carrying capacity of an ecosystem is exceeded, organisms with more suitable straits for the specific environment will survive and reproduce more than that of an organism with non suitable traits.
Fossils - Evidence of Evolution
- preserved remains of organisms that lived in the geological past
Many recently discovered fossils form series that trace evolution of modern species from extinct ancestor organisms.
Ecological - Evidence of Evolution
homologous structure, analogous structures, vestigial structures
structures that are inherited from ancestors but have lost much or all of their original function due to different selection pressures acting on the descendant
- ex. in dolphin ancestors, hipbones played a role in terrestrial locomotion; as the dolphin lineage adapted to life at sea, the function was then lost
- made by humans
- nature provides the variations and humans choose what they find useful
- driven by man usually for the purpose of man
- based on needs or opinions of humans
- made by nature
- based on what trait of specific organisms allows them to survive
- the process by which organisms with variations most suited to their local environment survive and leave more offspring (compared to organisms with variations not suited to their environment in which these variations usually go "extinct")
a group of similar organisms that can breed and produce fertile offspring
the process in which two completely different species develop similar traits
the process in which evolution produces organisms that start at one place but splits in different directions (Y shaped graph)
- a type of divergent evolution
the process by which a single species or a small group of species evolves over a relatively short period of time into several different forms that live in different ways or lifestyles
structures with common structures but different functions
structures with different structures but common functions