Macroevolution Flashcards
What is macroevolution?
Evolution over geological time of groups larger than 1 individual
Speciation?
Process of how a new species evolves
Biological species
Group of organisms that can reproduce with one another in nature and produce fertile offspring
How do new species arise?
Some members of a species must become reproductively isolated from the rest of the species, when two populations are separated their allele frequency changes. Since they no longer have migration between the population two separate species develop
Allopatric Speciation
When GEOGRAPHICAL BARRIERS divide a population, followed by the development of mechanisms in the separate populations that prevent interbreeding
What is the most important factor in starting speciation
Geographical Isolation
PHYSICAL AND BEHAVIOURAL CHANGES
- develop and keep 2 species isolated from interbreeding… ex. shrimp between the carribean seas have become different species and communicate, collect food, etc. diff.
Reproductive isolation
- formed by geographical isolation
- any factor in nature that prevents interbreeding
(breeding in a close population) between individuals of the same or closely related species
Extrinsic Isolating Mechanism
Outside of the organisms In question EX. GEOGRAPHIC ISOLATION
Intrinsic Isolating Mechanism
Internal characters that prevent interbreeding
Diff in anatomy, physiology, and behaviour
ECOLOGICAL, TEMPORAL, BEHAVIOURAL, MECHANICAL, GAMETIC, HYBRID INVIABILITY
Ecological Isolation
When 2 species have diff habitats they will rarely have contact…
Ex. Lions–grasslands, tigers–forests
Liger- won’t survive in the wild, not meant to exist
Temporal Isolation
- 2 species that share the same habitat but dont mate within the same time grame
- 2 populations of the same species of plant release their pollen at diff time of the year, if their reproductive periods didnt overlap they would’ve reduced gene flow
Behavioural Isolation
- even if populations are in contact and breeding can occur, they must choose to mate
- such a choice is based on SPECIFIC COURTSHIP AND MATING DISPLAYS
Ex. Albatrosses are behaviourally isolated from other bird species by their elaborate species—specific courtship behaviour
Mechanical Isolation
Reproductive organs differ in size/shape/another feature
Diff species of alpine butterflies look similar but have different reproductive organs
Gametic Isolation
Even if mating occurs, offspring may not result if there are INCOMPATIBILITIES between sperm and egg/sperm and female reproductive tract