B4.2 Ecological niches

Question 1

what does a species niche depend on

Answer 1

not only where it lives, but also on what it does
includes the biotic and abiotic interactions that influence the growth, survival and reproduction of the species

Question 2

why can no two species have the same niche

Answer 2

the niche completely defines a species and the role that species has in an ecosystem.
Two organisms can temporarily occupy the same niche

Question 3

example of two similar species occupying different niches

Answer 3

cormorant and shag are similar species of bird that live and feed along the coastline and rear their young similarly.
They share habitats yet diet and behaviour are completely different
thus they occupy different niches

Question 4

why did aerobic niches start to occur

Answer 4

aerobic niches evolved to avoid competition with anaerobic niches
anaerobic species that retreated into envrionments lacking oxygen

Question 5

obligate aerobes

Answer 5

microorganisms that can only respire aerobically

Question 6

obligate anaerobes

Answer 6

only respire in the absence of oxygen

Question 7

facultative anaerobes

Answer 7

respire aerobically but have the facility to switch to anaerobic respiration in the absence of oxygen

Question 8

autotrophic

Answer 8

make their own organic molecules using an external source of energy

Question 9

heterotrophic

Answer 9

relying on a supply of ready made complex food substances
they usually directly/indirectly rely on plant nutrition

Question 10

holozoic nutrition

Answer 10

food is ingested, digested internally, absorbed and assimilated

Question 11

mixotrophs

Answer 11

some organisms are both autotrophic and heterotrophic
this makes their form of feeding mixotrophic nutrition

Question 12

osmotrophy

Answer 12

uptake of dissolved organic material

Question 13

saprotrophs

Answer 13

organisms that feed on dead organisms and on waste matter of animals

Question 14

chemosynthesis

Answer 14

when inorganic molecules are oxidized to release energy which then is used to produce glucose

Question 15

how do archaea create energy

Answer 15

they use sunlight as a source of energy but doesn’t use photosynthesis
they have light activated ion pumps to generate ion gradients

Question 16

chemoautotrophs

Answer 16

organisms that rae autotrophic but do not use sunlight to produce glucose

Question 17

purpose of masseter muscles

Answer 17

connect the skull with the jaw, enabling animal to grind plant material

Question 18

purpose of temporal muscles

Answer 18

pull up the jaw, allowing the animals to bite food

Question 19

how can evidence for diet be seen

Answer 19

teeth and muscle structure shows their type of diet

Question 20

aphids and their advantage

Answer 20

aphids have modified mouths called stylets which secrete pectinase allowing the stylet to slide between cell walls and access sucrose from phloem

Question 21

how do plants resist herbivory

Answer 21

cacti have spines and stinging nettles have thin hairs that secrete acid
nightshade is also able to cause paralysis
Oleander is able to contain toxic glycosides which cause death when eaten

Question 22

eyes adaptation of predators

Answer 22

have eyes on the front to enable better depth perception and estimate distance to prey better

Question 23

eyes adaptation of prey

Answer 23

have eyes on the side of their head so they have good view of surroundings

Question 24

warning colors in prey

Answer 24

tell predators that the prey species may be toxic
seen in poison dart frogs which can paralyze and kill predators

Question 25

some ways that prey adapted to predators

Answer 25

speed
mechanical defences
camouflage
chemicals
behavourial patterns

Question 26

how do canopy trees have a competitive advantage

Answer 26

first access to sunlight and can access all frequencies
allows them to grow large

Question 27

lianas and advantages

Answer 27

woody vines that start on the tree floor
shoot up using trees allowing them to access sunlight and rely on other plants for survival

Question 28

epiphytes

Answer 28

plants that grow on the branches
have advantages of canopy trees but with no expense of needing long stems
they form microhabitats for many species of animals
they can also send roots down to the floor, forming thick networks

Question 29

shade tolerant shrubs

Answer 29

grow on forest floor with only access to small amount of light
contain different pigments due to filtered light, giving them different color
often have large leaves and less flowering
strongly scented to attract pollinators with smell

Question 30

fundamental niches

Answer 30

the potential location of a species along an environmental gradient. Determined by interactions between abiotic and biotic factors

Question 31

realised niches

Answer 31

to essentially where an organism does live, rather where it could live

Question 32

intraspecific competition

Answer 32

competition between a species

Question 33

interspecific competition

Answer 33

competition between different species

Question 34

when does interspecific competition exist

Answer 34

when the niches of different species overlap

Question 35

how is degree of competition between species determined

Answer 35

determined by degree of overlapping

Question 36

competitive exclusion

Answer 36

if two species share the same resource at the same place and time, dominant will outcompete the others
inferior then dies or moves away

Question 37

how could competitive exclusion lead to defined niches

Answer 37

pressure that causes closely related species that live in the same habitat to have evolved separated niches
wouldve occured over periods of time
example seen in cormorant and shag birds