Major Patterns of Evolution Flashcards
What does adaptive radiation mean?
Rapid increase in # of species with a common ancestor, characterized by great ecological and morphological diversity
What is Allopatric speciation
speciation that occurs when biological populations of the same species become isolated due to geographical changes or social changes
What are benthic zones
Lowest ecological zone in a water body
What are limnetic zones
The open and well lit area of a freestanding body of freshwater
What is the biological species concept
Defies a species taxon as a group of organisms that can successfully interbreed and produce fertile offspring
What is coevolution
The influence of closely associated species on each other in their evolution
What is the founder effect
Reduced genetic diversity which results when a population is DESCENDED from a small # of colonizing ancestors
What is the diastema
the gap from front teeth to back (herbivores)
What are some characteristics of herbivores
long jaw, reach into things, keep eye level above ground level
What are carnassials for
- cut and shear meat = more efficient consumption
what is genetic drift
variation in genotype frequency in small populations because of CHANCE disappearance of particular genes
What are mechanisms of genetic divergence
- mutation
- genetic drift
- genetic flow
- non random mating
- natural selection
What are reproductive isolating mechanisms
a collection of evolutionary mechanisms, behaviours, and psychological processes critical for speciation
What is sympatric speciation
the splitting of an ancestral species into two or more reproductively isolated groups without geographical isolation
What is dispersal
- few members of a species move to new area
- leads to allopatric speciation
What is vicariance
separation of populations when physically split in two
What are two ways to get allopatric speciation
vicariance and dispersal
What are the three major types of predators snails face
- chipping (crabs and lobsters)
- Rasping predators (other snails and octopi)
- biting predators (fish)
What is a radula
for rasping predators, a rasping file like structure covered with tiny teeth… rasp through shell of prey to make a hole and suck the body out
What adaptations from chipping predators
hidden lip
thicker lip
What adaptations from rasping predators
- spikier mouth (can’t get close)
- ridges
What adaptations from biting predators
- spikier mouth
- bigger
- extra smooth = sticks to ground and slippery, hard to grab
- thick
What are characteristics of omnivores
- flat cheek teeth
- short canines
- not self sharpening
- not shearing cheek teeth
- mostly enamel (white)
What are characteristics of herbivores
- enamel worn off by grinding and exposes dentin
- sharp cheek teeth to break down cell wall
- gap /diastema = long jaw
What are characteristics of carnivores
- covered enamel
- carnasial
- molars may be absent
- space between back teeth next to carnassial
- shearing teeth
What is evolutionary arms race
predators evolved specialized weapons of attack and prey evolved specialized defences
