Evolution Flashcards
Evolution
Accumulation over time of inherited changes in populations, leading to species which are related
Darwinian fitness
Individuals ability to survive and reproduce
Adaptation
An evolved feature that enhances an organisms fitness
Population
A group of organisms of a single species living in the same geographical area
Species
A group of organisms with common ancestry and physical structures that are able to breed and have fertile offspring
Community
Group of populations composed of organisms with common ancestry, sharing similar structures, functions, behaviours, etc - freely interbreed in nature
Ecosystem
Interactive system composed of one or more communities and their abiotic (nonliving) environment
Biosphere
All of earths ecosystems considered together
3 goals of evolution
- How life evolved in a single evolutionary tree
- Explain why species exist
- Explain how species adapted (all related to Luca)
Essentialism
Organisms are created in species form
What did Linnaeus say?
Ancestral forms reflect evolutionary relationships, however he proposed that species don’t change
What did Darwin propose?
Published origin of species
- resources are limited in nature and there is a struggle for life
- survival of the fittest
- NATURAL SELECTION = driving force of evolution
Differential reproductive success
Better fit individuals have a better chance of leaving more offspring
What is the smallest unit of life that can evolve
A population
What doesn’t evolve
INDIVIDUALS don’t evolve they adapt
What does natural selection act on?
Phenotypes within a generation - variation must be partially heritable for natural selection to result in evolutionary change
Why does evolution take time?
Small evoluntary changes can occur rapidly but complex adaptations require accumulation of small changes over a long period of time
What were the 4 observations that natural selection was based on
- Variation
- High reproductive potential
- Individual compete
- Fitness
- Molecular biology
- Phenogentics
- Convergent evolution
- Anthropocene influence
How can we find evidence for evolution
- Fossil records
- Comparative anatomy
- Biogeography
- Comparative embryology
Fossil records
Date with radio-activity (not for all species because soft bodies don’t often leave fossils)
Comparative anatomy
Revels the existence of homologous structures (shared origin) beneath the phenotypical characters
Biogeography
Distinct classes of organisms found in limited areas which can only be explained by evolution from common ancestors historically restricted in those areas
Comparative embryology
Organisms that share a common ancestor but subject to different selection pressure during adulthood where shared differently in their adult structures but share common embryological stages
Molecular biology
All living organisms share the same building blocks - DNA sequences are a record or change over time
Phylogenetics
History reflects DNA,
- we can group species by shared species
- evolution is non-directional
Convergent evolution
The acquisition of the same biological trait in different lineages
- analogous structures: are shared function but not shared ancestry
Anthropocene influences
Artificial selection by humans creating new species based on selecting the best traits
What happened to the soapberry bugs
- when a new species was introduced into the population, the original food source was changed - an this change persisted leading to a genetic change
How old is life on earth
Life on earth is 4.6 billion years old
What did Miller-Urey experiment do?
Showed abiotic synthesis
- stimulated the conditions of early earth (little oxygen, lots of ammonia-menthane- water- and storms)
What is the pathway for how life began on earth
Inorganic molecules - organic molecules - self replicating organic molecules - aggregations - progenote
What is the last common ancestor
LUCA - cocestor that arouse from archaea and eventually began the first eukaryote
What was the evolution of prokaryotes
Life as a single cell with no nucleus
- limited to alter anatomy
- limited capacity to extend niches
- genetic variation is random
EX= Bacteria and archaea
*evolution of eukaryotes
Life as a protist - arouse from endosymbiotic hypothesis (evolution of the mitochondria/chloroplast)
- adapt or die
How did the mitochondria evolve
From a parasitic bacteria that had an efficient metabolism
What is the key evidence of mitochondria and chloroplasts
DNA sequencing analysis shows a relationship between mitochondria and non-sulphur purple bacteria
Because mitochondria produce a wide range of toxins (ROS) what did it drive selection for
- migration of mtDNA to nucleus
- maintence of nuclear envelope
- formation of peroxisomes
- evolution of more DNA repair mechanisms
How are mitochondria passed down through populations
the egg
Macro evolution
“Big evolution”
What are the two forms of macro-evolution
- Gradualism
- Punctuated equilibrium
Gradualism
The product of microevolution and adaptive divergence over a long period of time
Punctuated equalibrium
Very long and relatively quiescent periods interrupted by short intervals of intense species turnover
- spirts of evolutions = macro evolution
Adaptive radiation
Disaster that
