Evolution Flashcards
What are the 3 types of fossils?
- Body Fossils
- Trace Fossils
- Pseudofossils
What are homologous features
(Built ______)
Similar structures in various organisms that have different functions ex. humans, horses, cats and whales have similar bone structure
What are analogous features?
different structures in various arganisms that have similar functions
• no common ancestor
ex. eyes and wings of birds and insects
What are vestigial features?
features that do not have a functian ex. appendix, gooscbumps
Stabilizing selection
selection against two extremes of a trait that results in an in -
between trait ex. short plants vs tall plants = medium plants.
Directional selection
selection against one extreme of a trait that results in the
apposite extreme trait ex. peppered moth
Disruptive selection
selection against in between traits that results in 2 extremes
of a trait ex, mice on beach
Bottleneck effect
extreme example of genetic drift
large number from pepulation is greatly reduced
Founder effect
a small number of individuals establish a new populations
Genetic drift
Some individuals produce more offspring by chance genes of next generation will inherit the genes of “lucky”
Individuals random, happens to all species
Lamarack
Scientist that suggested that evolutionary change resulted from 2 principles
1. use and disuse
• Structures that were used became bigger and stranger while structures that were not used became smaller and weaker
2. inneritance of aquired characteristics
• Individuals can pass aquired characteristics to their offspring
theory of evolution = species evolve and adapt to ther changing
environment
Castrophatism
global castrophes cause widespred extinction of species
• these extinct species were replaced by newley createdones
Uniformitarism
earth has been changed by the same process in the past that are occuring in the present
• Old, slow moving evolutionary change
Artificial selection
domestication (not natural)
• humans choose individuals within a plant or animal species with desireable traits to be parents in hopes that these tralts are passed down examples
• dogs are domesticated wolves
• effective but siow, can take multiple generations Limitations
• breeders cannot create traits that are not already present
• can make population uninerable to discase
• we lose genetic diversity
• a favoured allele could be linked to a detrimental trait
Adaptations
different features in a species that improves their chances for survival in a specific environment
• physical or behavioural
• ex. sharper teeth, longer hibernation period