Species and Niche

Question 1

name the 7 problems with species definitions

Answer 1

1) parthenogenesis
2) apoximis
3) widely distributed species
4) polyploids
5) hybridisation is effectively separated species
6) natural hybridisation
7) polymorphism

Question 2

describe parthenogenesis

Answer 2

a natural form of asexual reproduction where fertilisation of the egg is not required to develop an embryo and individual.

mostly female offspring, but one individual could found a whole new population

(Moritz 1991)

Question 3

describe apoximis

Answer 3

the ability of some plants to produce seeds and offspring without fertilisation e.g. blackberries (Amsellem et al 2001)

Question 4

describe how polyploids interfere with species definitions

Answer 4

cells contain multiple sets of chromosomes, but are technically same species. BUT infertile offspring between diploids and polyploids of same speccies

Question 5

describe ‘ring species’

Answer 5

species distributed over such large areas that individuals from opposite ends may vary considerably – races are formed, and only neighbouring races may interbreed – genetic isolation through geographical distance

Question 6

give 2 examples of ring species

Answer 6

greenish warbler has a ring around the himalayas

Larus gulls have a ring around the north pole (Wake, 2001)

Question 7

how is hybridisation between effectively separated species an issue to the species concept

Answer 7

Individuals of populations (which may already look and behave quite differently) may be able to successfully breed, but will never (hardly ever) do so under natural conditions e.g. tiger+lion=liger/tigon
e.g. geese.

Question 8

which 3 factors create issues for the field identification of species

Answer 8

hybridisation
(e.g. orchids)

polymorphism
(e.g. many strawberry poison frog morphs)

polymorphism
(sexual dimorphism in mallards and tanzanian butterflies (keilland 1990))
(seasonal dimorphism in map butterflies)

Question 9

define fundamental niche

Answer 9

the full range of resources an organism requires to replace itself

Question 10

define realised niche

Answer 10

that part of the fundamental niche an organism occupies in the field

Question 11

why is there a difference between the realised and fundamental niche?

Answer 11

organisms are best able to compete in their optimal growth conditions, so interspecific competition is there

(ellenberg et al 1992)

Question 12

when are organisms most competitive

Answer 12

optimal growth conditions

Question 13

example of spatial resource partitioning for niche differentiation

Answer 13

root systems of european herbs occupying different depths

Kutschera and Lichtenegger (1992)

Question 14

how do species coexist

Answer 14

niche differentiation - using the same environment is a different way, usually through spatial or temporal partitioning

Question 15

which disturbances could be exploited for temporal partitioning in niche differentiation

Answer 15

falling trees
gaps
clearings
fire
trampling

Question 16

how is nutrient level affected by clearing forests

Answer 16

wood is harvested, removing nutrients from the ecosystem

Question 17

how is nutrient level affected by fire?

Answer 17

fires lead to a sudden nutrient flash, which is washed away at the next rain, leaving very poor nutrient levels

Question 18

3 examples of fire being used in niche differentiation

Answer 18

fire on mt Kilimanjaro has enabled sub-alpine forests to be replaced by bushes. These burn and are replaced by other bush species

seed capsules in Australian pyrophytes only open when a fire occurs

seed pots in a different australian pyrophyte only opens after a fire

Question 19

what will happen if coexisting species don’t differentiate into niches

Answer 19

If there is no differentiation, or it is precluded by the habitat, then one competing species will eliminate or exclude the other.

Question 20

what is the biological species concept?

Answer 20

Species are groups of actually or potentially interbreeding natural populations that are reproductively isolated from other such groups

Question 21

what is the phylogenetic species concept

Answer 21

a species is defined as the smallest set of organisms that share common ancestors and can be distinguished / are isolated from other such sets.

Question 22

who coined the biological species concept? when?

Answer 22

(Mayr 1942).

Question 23

what is allopatric speciation

Answer 23

a barrier forms between a population, with different environmental conditions on the other side, and no more gene flow.

Question 24

example of allopatric speciation

Answer 24

squirrels on either side of the grand canyon

Question 25

what is peripatric speciation

Answer 25

a few members from a population get moved to another location (by humans, a storm etc), with new niches, and are in reproductive isolation, so they evolve e.g. galapagos iguanas

Question 26

what is sympatric speciation

Answer 26

speciation in the same geographical space. genetic polymorphism causes a change, selection pressures cut off the hybridisations/ in between stages, leaving 2 separate species

Question 27

give an example of sympatric speciation via mimicry

Answer 27

heliconius butterflies

start to evolve to mimic a different butterfly but intermediate species in the evolution process are disadvantaged, causing evolved individuals to only mate with other evolved individuals

(Jiggins et al 2001)

Question 28

give an example of sympatric speciation through resource utilisation

Answer 28

apple maggot flies

evolved to lay eggs in hawthorne apples. these ones now don’t like to mate with others, thus reducing gene flow as a result of the host shift
(Berlocker et al 2002)

larch budworms

some feed on larch, others on pine. they only like to mate with their peers (emilianov et al 2001)

Question 29

what is adaptive radiation

Answer 29

rapid speciation of one species into many to fit new niches in a new environment, such as if moved to a new island.

e.g. darwin finches

Question 30

what is assortative mating

Answer 30

individuals of one type prefer to mate with those similar to themselves over others within their species

Question 31

What is the scale hierarchy of ecological study

Answer 31

From smallest to largest, autecology > population ecology > community/ecosystem ecology > landscape/geo-ecology

Question 32

Is the phylogenetic or biological species concept better for classifying extinct species

Answer 32

The biological species concept puts emphasis on breeding ability, which cannot be measured in extinct animals, so the phylogenetic one is better

Question 33

How can different resource utilisation lead to sympatric speciation

Answer 33

Organisms move to different resource to use that resource, and evolve to better suit it

Question 34

What is natural hybridisation

Answer 34

orchids all interbreeding between clearly different species

Question 35

What is polymorphism

Answer 35

Genetically same species with completely different morphs

Question 36

What is sexual dimorphism

Answer 36

Species where male and females look very different - can be accidentally classified as different species

Question 37

What is seasonal dimorphism

Answer 37

Species with completely different morphs across seasons

Question 38

what is a species response curve

Answer 38

curve showing which extremes of a specific condition a species can survive, reproduce, and/or grow under

Question 39

predation response evolution between acacia and giraffes

Answer 39

growing large spines, or encouraging ant nests to be in the leaves to drive giraffes away

Question 40

which journal article refers to temporal partitioning in tree fall

Answer 40

luttge 1997

Question 41

examples of niche differentiation by temporal partitioning

Answer 41

a tree falls, creating a gap. Plants growing to begin with grow for a while, and are outcompeted by other specied slowly over and over and over again, allowing many species to use this space across time

Question 42

which journal article refers to niche differentiation by resource partitioning

Answer 42

kutschera et al 1992 - roots, nentwig et al 2004 - birds on pine

Question 43

which journal article refers to the niche concept

Answer 43

ellenberg et al 1992 - beech, oak, birch, pine: realised vs fundamental niche