evolution Flashcards
theory of evolution
- replaced the theory of special creation
- species evolved over time
theory of special creation
- each species is a unique type created by god
how are fossils evidence for evolution?
- they are physical traces of organisms
- they can be dated back with various techniques
- they provide history of life
what are vestigial traits?
-structures that have no function but it’s similar to a functional structure in a related species
what can vestigial traits show?
- evolution happens in gradual steps
how is extinction evidence for evolution?
- many fossils have been left of organisms that no longer exist and shows that species are changing
- however this isn’t convincing evidence
what are transitional forms and why are they relevant?
- when a species disappears from the fossil record (a collection of all known fossils) a similar species often appears (usually in the same geographic area)
- this is consistent with species evolving
why are relationships between species important?
- if species evolved from a common ancestor, it’s expected that there would be evidence to show that they would be related
what are geographic relationships?
- the concept that species from the same area seem to be related
- supports the idea that these species originally came from a common ancestor
what is homology and how do they support evolution?
- a similarity due to common ancestry
- similarities due to homology are widespread which shows how strong evolution can be
genetic homology
- similarity at the DNA/genetic level
- the genetic code is basically shared by all living organisms
developmental homology
homology in the traits of embryos (developing organisms)
structural homology
similarity at the level of developed organisms
how can we identify homologies/ know similarities are due to common ancestry?
- the idea of homologies seem to explain many observed patterns
- organisms fall naturally into groups
- genetic & morphological evidence seems to agree with homology
who developed the theory of natural selection?
lamark
- not he was wrong in a sense as he thought acquired characteristics were inherited
the 4 ways that natural selection drives evolution
- variation
- heritability
- differential reproductive success
- selection
what is variation?
the individuals in a population must have variation in their traits
what is heritability?
the varying traits that the individuals must have must be able to be passed down from generation to generation
what is differential reproductive success?
in each generation, some organisms must have more offspring than others
what is selection?
the reproductive success isn’t random but must be able to be influenced by the trait differences
whats the important thing that must be remembered about natural selection?
natural selection acts on individuals but only populations evolve
2 things that must have for evolution by natural selection to occur
heritable variation in traits & selection (differential reproductive success) based on these traits
what is darwinian fitness?
- the ability to do well under natural selection
- like better reproductive success, with heritable traits q
what are the components of darwinian fitness?
survival, growth, reproduction