Patterns of Descent with Modification Flashcards
a process that gradually selects the organisms that are better adapted to their environment
Biological Evolution
CONTINUOUS PROCESS which has been CHANGING AND FORMING LIFE IN EARTH FOR BILLION OF YEARS
Evolution
GROUPS OF INTERBREEDING NATURAL POPULATION that are reproductively isolated from other such group
SPECIES – ERNST MAYER’S DEFINITION
a closely related organism that are very SIMILAR AND CAPABLE OF PRODUCING FERTILE OFFSPRING
SPECIES – ERNST MAYER’S DEFINITION
Prevent fertilization and zygote formation
PRE-ZYGOTIC ISOLATION MECHANISM
Occurs when two species that could interbreed do not because the species live in different areas
GEOGRAPHIC/ECOLOGICAL/HABITAT ISOLATION
Different groups may not be reproductively mature, making mating impossible
TEMPORAL/SEASONAL ISOLATION
“PATTERNS OF COURTSHIP” When two populations are capable of interbreeding but don’t since they have differences in reproductive strategies that involve behavior.
BEHAVIORAL ISOLATION
Differences in reproductive organs prevent successful interbreeding
MECHANICAL ISOLATION
Incompatibilities between egg and sperm prevent fertilization
GAMETIC ISOLATION
Allow fertilization but non-viable or weak or sterile hybrids are formed
POST-ZYGOTIC ISOLATION MECHANISMS
Fertilized eggs fail to develop past the early embryonic stages.
HYBRID INVIABILITY
Hybrid fails to produce functional gametes
HYBRID STERILITY
Two organisms are able to mate and produce viable and fertile offspring
HYBRID BREAKDOWN
The evolutionary process by which populations evolve to become distinct species.
SPECIATION
