Patterns of evolution Flashcards
What is cladogenesis?
one lineage spilts into two descendant lineages
What is anagenesis?
gradual evolutionary changes within one single lineage
What is gradualism? (not in the geology sense)
Gradual change over time
What is punctuated equilibrium?
periods of little to no evolutionary change followed by rapid change following a catastrophe
What is pseudoextinction?
A taxon changes by anagenesis until it is so different from the ancestor it is classified as something else, but the ancestor became the descendent instead of actually going extinct
How does ontogeny recapitulate phylogeny?
Ancestral traits can be present in the embryo/larvae, but absent in the adult form
What is heterochrony?
An evolutionary change in phenotype caused by a change in the timing of developmental events
Which type of cells typically grows faster, somatic or germ-line?
Somatic
What is paedomorphosis?
A larval stage becomes sexually mature without gaining its adult characteristics
What are the two types of paedomorphosis?
Progenesis and neoteny
What is progenesis?
When the development of reproductive cells gets accelerated and causes growth of the organism to stop sooner
What is neoteny?
When the development of the somatic cells slows down and a larval stage reaches sexual maturity without its adult characteristics
What is adaptive radiation?
Diversification of a lineage into forms that fill different niches rapidly in all directions
Why is adaptive radiation probably the most common pattern of long-term evolution?
It happens following any extinction event
What is a species flock?
A group of closely related individuals all living in the same ecosystem
How do species flocks occur?
Repeated speciation events in a single ancestral species that caused it to diversify in the same ecosystem - the cichlids
What distinguishes a species flock from other members of the same species not part of the flock?
They have one or more synapomorphies that relatives outside the flock don’t have
What is Mullerian mimicry? Who benefits? Which of the two species is more numerous?
Both species are poisonous or distasteful, and they reinforce the same signals to predators. Both benefit and they are both in roughly equal proportions
What is Batesian mimicry? Who benefits? Which of the two species is more numerous?
Only one species is dangerous, the other is harmless and is mimicking the colours or behaviours of the dangerous one. Only the mimic benefits and there are usually a lot less of them
What is pseudocopulation?
A flower mimics a female insect and the male pollinates the flower when he tries to copulate
