Evolution Flashcards
What is evolution?
The process of organisms adapting over time due to environment, competition or mutation that leans towards phenotypes best adapted for survival so the genotypes can be passed on to successive generations (survival of the fittest)
What are the 4 main routes of evolution?
Natural selection
Common ancestor theory
Speciation
Extinction
How does extinction lead to evolution?
- reduces diversity
- can lead to bottle-necking
- threats lead species to select away from vulnerable phenotypes
- New stressors
What is the common ancestor theory?
Darwin’s theory that states different species of living organisms can ultimately be traced to a single common ancestor
In theory it suggests all forms of life can be traced back to a single universal common ancestor
Which two theories make up Darwin’s theory of evolution?
Common ancestor theory
Natural selection
How does the common ancestor theory lead to evolution?
Over time speciation has occurred from one single universal ancestor
Name 3 pieces of evidence for the common ancestor theory
- Common biochemistry - DNA and RNA
- common genetic code - amino acid bases always code for the same proteins (in plants, animals and bacteria)
- Selectively neutral similarities NOT as a result of convergent evolution
- Use of ATP
- Phylogenetic trees - similar DNA, morphology, embryology
What is one main factor opposing the common ancestor theory?
Convergent evolution
- it is the environment causing similarities NOT a common ancestor’s DNA etc
Name 3 types of speciation
Allopatric
Sympatric
Artificial
(Also accept Peripatric and Parapatric)
What is allopatric speciation?
where the two populations are physically isolated
What is sympatric speciation?
when two populations are reproductively isolated in the same environment
What is artificial speciation
the creation of new species by people
Give an example of artificial speciation
Domestic sheep - interbreed two species to create a hybrid
What is peripatric speciation
When small groups of individuals break off from the larger group and form a new species
What is parapatric speciation
when a species is spread out over a large geographic area
Name 5 factors that can cause isolation
Geographic
Temporal - climate may cause different spawning times
Behaviour - mating calls may be altered (causes ‘accents’)
Mechanical - structural differences
Hybrid sterility - mules, ligers
What is extinction
the end of an organism/ group of organisms (taxon) – normally a species
How may sympatric speciation occur?
- changes in temps may cause different spawning times (frogs)
- mating calls may differ (accents)
- hormonal changes, pheromones
How may allopatric speciation occur?
Habitat fragmentation:
- Earthaquakes/ natural disasters
- hedges cut
- road built
- landscape development
What is adaptive radiation?
The divergence of a single group (or species) into a series of distinct but related groups.
- i.e: Darwin’s finches
Name an example of adaptive radiation
Darwin’s finches - each finch was adapted to survive in its specific niche
what does ecophysiology mean?
- branch of physiology that deals with the physiological processes of organisms with respect to their environment
Name 3 ways ecophysiology of an animal may change
- Range shifting - moving to areas of different temps, water availability etc
- Morphological changes - i.e: coat colour, body mass
- Breeding changes
- Behavioural changes - nocturnal activity in Arabian oryx; eating different diets
What are 3 conditions that make animals better suited to adapt to climate change?
Large populations (good gene flow) Genetic Diversity Short generations (can quickly adapt to stressors) Generalist species (not specialists) Only having one stressor at a time
