Distributions, Migration And Dispersal Flashcards Preview

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Flashcards in Distributions, Migration And Dispersal Deck (16)
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1

When did the first mammals appear

Triassic, they were egg laying

2

When did modern mammals (placentals, marsupials) evolve?

100mya, late Cretaceous

3

What are some of the wandering families?

Shrews, dogs, cats, mustelids, bovids

4

When did angiosperms (flowering plants) arise?

130mya, modern angiosperms around 95mya

5

How many species of flowering plants are there?

300,000

6

What are the advantages of angiosperms?

- tough leathery leaves, drought resistant
- resistant seed coat prevents desiccation
- efficient water conducting vessels
- fast speciation rates

7

Why did angiosperms diversify so quickly?

Because of insect-angiosperm evolution

8

What are cosmopolitan taxa?

Taxa that occur in all/most regions of the world
Few truly cosmopolitan (humans)
House sparrow in most, migrated with humans

9

Give examples of wide spread taxa (in suitable habitats)

Penguins - cold lower latitudes
Heather - western oceanic Europe
Cacti - north central and South America

10

An example of a disjunct taxa?

Marsupials, abundant in Australia, but some many 1000s km away in S America

11

What are endemic species?

Species found only in one well defined region
Eg. Finches found on individual islands of Galapagos
red grouse, Britain

12

Greater similarity in plants of S America, Africa, Oriental, Australia than mammals, why?

1. Plants evolved and dispersed earlier than mammals
2. More extinction of mammals
3. Greater modern dispersal ability of plants

13

Climatic relicts, give an example

The arctic spring tail,
Arctic springtail - 2x8 eyelets
Pyrenees springtail - 2x6 eyelets

14

Why is plant dispersal so successful?

1. Seeds are v resistant
2. Self fertile, one seed can be successful
3. Ariel dispersal
4. Primary producers, self sufficient

15

Animal dispersal, why easy but why not easy?

Easy - mobile - potentially rapid migration eg. Starling from New York to Canada in 50years
Hard - most animals need 2 individuals of opposite sex to breed
Many insects have 1 single food source
May carry parasites and diseases

16

What are the environmental influences on migration?

Corridors
Barriers
Filters (allow specialist species through)
Bridges