1. E1. Populations are the units of communities.

2. E1.1 Know that a community is made up of localised, interacting populations.

3. Key terms
individual
population
community
ecosystem
abiotic
biotic

4. E1.2 Explain that populations in a community consist of different species, and know the characteristics that define a species.

5. Species members of populations interbreed or potentially interbreed
fertile offspring
gene flow is prevented or limited

6. Appearance isn’t everything
identical appearance
ranges overlap
distinct songs prevent interbreeding
separate species
Western meadowlark
Eastern meadowlark

7. Appearance isn’t everything
Sexual dimorphism
Pheidole barbata
Scarce Vapourer - Orgyia recens
Indian peacock - Pavo cristatus

8. E1.3 Give examples of mechanisms that maintain the reproductive isolation of species in a community.

10. Reproductive barriers between species
Habitat - different locations
Behavioural - mating rituals, no attraction
Temporal - timing of mating, flowering
Mechanical - structural differences
Gametic - gametes fail to unite
Hybrids die in development, are weak or infertile

11. Courtship ritual in blue-footed boobies is an example of behavioural isolation
Many plant species have flower structures that are adapted to specific pollinators
mechanical isolation
Figure 14.2A, B

12. Hybrid sterility is one type of postzygotic barrier
A horse and a donkey may produce a hybrid offspring, a mule
Mules are sterile

13. If reproductive barriers are overcome we get
HYBRIDS

14. Female tiger X
Male lion

15. LIGER

16. X
Female lion
Male tiger

17. TIGON

18. Pony X
Horse
Zebra
Donkey

19. ZONY
ZEBROIDS
ZORSE
ZONKEY

20. X
Polar Bear
Grizzly Bear

21. GROLAR/PIZZLY BEAR

22. GROLAR/PIZZLY BEAR
Generally hybrid animals only occur within captivity as there are many reproductive barriers to isolate the two species. Polar bear – living in ice/water & breeding on ice Grizzly bear – living and breeding on land Theory 1: interbreeding has always happened Theory 2: melting of ice caps causes migration

23. Llama X
Camel

24. CAMA

25. canis lupus familiaris
subspecies of the grey wolf
various breeds
same subspecies