Darwinian evolution Flashcards
Natural selection
Organisms best suited for their environment are more likely to survive and pass on their traits to future generations
Charles Darwin
Famous scientist who traveled on the HMS beagle and made the theory of evolution by using natural selection as a mechanism
Origin of species
Charles Darwin published the origins of species to describe the divergence of species from a common ancestor
- book laid the foundation for evolutionary biology
Malthus
An economist that published “on populations” and believed that the human population groans rapidly but limited resources and. Illness keeps it in check
Darwin learnt from Malthus that….
Darwin knew that populations could grow faster than their resources which led to overpopulation
- Darwin called this the struggle for excistence because populations are maintain due to organisms struggle to acquire their needs
Lyell
A geologist along with James Hutton that proposed the idea of uniformitarism (earth was much older than realized)
Uniformariamism
Earth was much older than realized
Darwin learnt from lyell
Assumed like Lyell, that earth was very old because a long time was needed to pass inorder for evolution to occur
James batiste Lamarck
A French biologist who proposed his theory of inheritance of acquired characteristics to provide an awnser to how evolution works
- stated that all living things have an innate drive for prefection
Theory of inheritance of acquired charcteristics
Stated that bodies of organisms are modified through the use and disuse of a trait and these modifications are inherited by offspring
Darwin learnt form Lamarck
Assumed like Lamarck that species can change over time
Due to evidence found in fossils
Lamarck v/s Darwin (giraffe)
Lamarck: giraffes stretch their necks as they keep reaching for higher foods in taller trees and over time their necks begin to elongate and when they reproduce their offspring Will inherit a longer neck
Darwin: if the giraffes enviorment changed and the leaves became scarce, it led to a struggle for excistence because longer neck giraffes had an advantage since they could reach leaves that over giraffes couldn’t. As a result longe neck giraffes were most likely to survive and reproduce passing those advantages traits to their offspring and as a reuslt each generation contained more longer neck giraffes until all giraffes had longer necks
Fitness
An organisms ability to survive and reproduce fertile offspring
Darwin v/s Wallace
- Both coined the same idea of evolution
- worked together/ published origins of species
- coined theory of descent with modification (each generation is different from the others)
Darwin’s observations
- Population can have the potential to grow rapidly (overpopulate)
- Population tend to stay relatively stable in size
- Population are stable due to limited resources in their enivorment
- There is variation among organisms in a population
- Indivisuals with advantages variations have a better chance of surviving than those with the less advantages
Mutations and phenotypes
New mutations provide new phenotypes and leads to evolution
Evidence for evolution
Direct observations, comparative homology, fossil record, and biogeography
Direct observation
Study species in real time to see how they change over time
Ex: drug resistant bacteria
Comparative homology
Study of similarities and differences in the structure of different species
- includes homologous and analogous structures
Homolgous structures
Structures that are similar in related organisms because they were inherited from a common ancestor
- different functions but similar internal structures
- EX of divergent evolution (common ancestor)
Ex: they all have the same basic pattern of bones because they inherited this pattern from a common ancestor
Analogous structures
Structures that are similar in unrelated organisms
- similar functions but different internal structures
EX: the wings of bats and insects because they both fly but the bone structure is differnt
- ex of convergent evolution (different ancestory)
Comparative embryology
Study of the similarities and differences in the embryoys of different species
- similarities= share a common ancestor
- similarities between embryoys may be gone by adulthood
Vestigial structures
Structures that are no longer used and serve no function
Ex: human tailbone, wisdom teeth, appendix, and whale pelvis
- evolution reduced the size of vestigial structure because they are no longer used
Evolutionary trees
Provides a hypotheses about the relationships among different groups
Convergent evolution
Doesn’t provide information about ancestry
Molecular analysis
Steps to show relatedness among organisms
- all cells have dna, rna, use atp, chromosomes, and 20 amino acids
The fossil record
Record of life that unfolded over 4 billion years ago and was pieced back together through he analysis of fossils
Fossils
Preserved remains or traces of organisms that lived in the past
- evidence of evolution because they show how a species lived in the past
Transitional forms
Suggest new species evolved form and replaces previous species
Paleontologists
Scientists that study fossils
Biogeography
The study of how and why plants and animals live where they do
- a species spreads apart and lives in different places around the world
Adaptive radiation
Process by which a single species evolves into many new species to fill available niches
