dispersal, colonisation & invasion

Question 1

Dispersal by Diffusion

Answer 1

gradual expansion of species geographic range into adjacent area

Question 2

Jump dispersal

Answer 2

new populations established far ways from species range limit

Question 3

Biogeographic barrier

Answer 3

geographic feature that blocks dispersal and colonisation (ocean desert, mountain)

Question 4

Biogeographic corridor

Answer 4

• geographic feature which promotes dispersal and colonisation of all taxa on either side
• continuous area of similar climate/vegetation
• eventual harmonisation of biota on either side `

Question 5

Biogeographic filter

Answer 5

• geographic connection that allows only a sub-set of species to pass through
• physical/biological factors favourable to passage of some species, but not others
• results in distinct biotas on either side

Question 6

Biogeographic stepping stones

Answer 6

• island chains
• a type of filter
• Indonesian and Philippine islands (stepping stones for dispersal between Asia and Australia)

Question 7

Biogeographic Sweepstake’s

Answer 7

• very low probability of dispersal
• ‘jump dispersal’
• crossing an ocean
• reaching distant islands

Question 8

Biogeographic Invader

Answer 8

• Exotic species introduced to new area by humans

- 50-70% of agricultural weeds in North America are Eurasian in origin