Unit 5 Chapter 22 reversed Flashcards
(31 cards)
heritable change in population of organsisms from one generation to the next
evolution
traits are heritable and variation exists within a given species
variation
Process in which individuals with favorable inherited traits are more likely to survive and reproduce
natural selection
genes conferring beneficial traits
adaptions
human population grows more rapidly than food supply does until famines/ war/ disease reduce population
Malthus
perceived that changes in Earth’s surface can result from slow, continuous actions still operating today
Hutton & Lyell
mechanisms he proposed aren’t supported by scientific evidence
- change occurs through use and disuse
- inheritance of acquired characteristics
- organisms have innate drive towards greater complexity
- evolution by natural processes
Lamarck
suggested that existing species are derived from pre-existing species
Observed many examples of adaptations
• Darwin’s finches’ example of adaptive radiation
Limit to resources=limit to populations
• Only the fittest can survive
Favorable variations will be selected for (weaker are outcompeted)
Stronger variations will persist over weaker in struggle for existence
Darwin
descent with modification- the 3 broad observations about life
unity of life
diversity of life
match between organisms and their environment
refers to the human interaction bc humans have selectively bred domesticated plant and animal species
artificial selection
Shows successive evolutionary change
Form many ways and preserve evidence of a huge variety of organisms.
Comparing these by age allows us to see successive change
Earliest are from oldest rocks
• (old rocks have simple life forms)
this record is incomplete bc some organisms don’t fossilize
• Erosion and movement can destroy them
Transitional forms can be difficult to find
fossil record
study of geographic distributions of extinct and living species
biogeography
demonstrates principle species change over time
selective breeding
two different species evolve independently from different ancestors but have adapted to similar environments in similar ways
convergent evolution
similarity resulting from common ancestry
homology
HGT causes this and molecular processes underpin evolution
molecular homology
these similarities are most obvious
anatomical homology
these differences can be used to gauge evolutionary relationships
developmental homology
in local environment, these determine what traits are useful and which are selected for
selective pressure
share features because of convergent evolution
analogous structures
anatomical resemblances that represent variants on a structural theme present in common ancestor
can be heritable—DNA sequence, protein structures, anatomical structures, behavioral patterns
homologous structures
anatomical feature that has no current function but resembles a structure of a presumed ancestor
vestigal structures
which (one of two) type of structures is convergent evolution
analogies
which (one of two) type of structures is divergent evolution
homologies
