3.2 Origins Of Biodiversity Flashcards
What does biodiversity arise from?
Evolutionary processes
Evolution
Cumulative gradual change in the general characteristic of a successful generation of a species of an organism
Natural selection
Proposed mechanism that can lead to the formation of new pecies
4 steps of natural selection
Step 1: genetic diversity occurs as a result of mutation in genes
Step 2: some individuals will have advantages due to their genes
Step 3: these species will survive due to natural selection
Step 4: over time this is how new species are formed
Speciation
Formation of new species
Occurs when Natural selection and isolating mechanisms are combined
Geographical isolation
When two populations are separated by a physical population no the two different pecks evolve differently as a result of natural selection
Reproductive isolation
Factors preventing species from interbreeding: environmental isolation, temporal isolation (timing of their activities), behavioural isolation, mechanical isolation (physical differences in organisms)
Plate tectonics
Theory that the earth’s outer covers are divided into plates
Destructive plate margins
Plates that move together
Constructive plate margins
Plates that move apart
Collision plate margins
Plates that collide
Effects of plate on biodiversity
Separation f continental plates can result in isolation of species, plate activities can create new islands, new climate regions
Mass extinction
Periods in earth’s history when very large number of species des out simultaneously or within a short time
Five mass extinctions
Ordovician-Silurian extinction: 440 million years ago
Devonian extinction: 365 million years ago
Permian-Triassic extinction: 250 million years ago
Triassic-Jurassic extinction: 210 million years ago
Cretaceous-tertiary extinction: 65 million years ago
What is the sixth mass extinction?
It is considered to be lung on right now caused by humans
