topic 2: ecosystems and ecology Flashcards
(57 cards)
1
Q
species
A
- can reproduce to have fertile offspring
2
Q
ecosystem
A
- community of interdependent organisms and the physical environment they interact with
- made up of biotic and abiotic components
3
Q
biotic components
A
- producers plants that convert energy into matter - consumers animals that eat plants or other animals - decomposers organisms that breakdown waste into parts able to be reused - interactions between living components predation, herbivory, parasitism, mutualism, disease and competition
4
Q
populations
A
- species live together in groups called populations
- births and immigration increase population size
- deaths and emigration
decrease population size
5
Q
abiotic components
A
- temperature
- sunlight
- pH
- salinity
- precipitation
6
Q
habitat
A
- natural environment around the organism
- has the physical and biological resources an organism needs to survive
- physical
soil, moisture, temperature, sunlight - biological
food, mate, predators
7
Q
niche
A
- smallest unit of a habitat
- how an organism fits into an ecosystem
8
Q
fundamental niche
A
- tolerance range for abiotic factors in their environment
9
Q
realized niche
A
- the niche the species actually occupies, usually due to competition of others
10
Q
J-shaped growth curve
A
- exponential population growth
- ideal conditions, plenty of resources and limited competition
11
Q
predation
A
- one predator hunts and kills the prey to gain energy for survival and reproduction
- can be individual, group or plant
- prey usually higher than predator numbers
- populations peak out of sync
12
Q
herbivory
A
- consumption of plant material by an animal
- plants can produce enzymes/ thorns to reduce herbivory
- animals can adapt, strong tongues for thorns etc
13
Q
parasitism
A
- when a parasite takes nutrients from the host
- parasites can live inside or outside the host
14
Q
mutualism
A
- two organisms of different species exist in a mutually beneficial relationship
- oxpecker eating ticks on herd of animals
15
Q
disease
A
- departure from normal state of functioning
- can impact the whole body or just parts
16
Q
competition
A
- organisms compete for a limited resource
- intraspecific, same species
- interspecific, different species
17
Q
primary producers
A
- convert inorganic compounds into food
- base of the food chain
- most make their food through photosynthesis
18
Q
consumers
A
- also known as heterotrophs
- can’t make their own food, get it by consuming other organisms
- herbivores, carnivores, omnivores
19
Q
decomposers and detritivores
A
- gain energy and nutrients from dead plant and animal material/waste
- ie bacteria and fungi
- metabolise waste and release as inorganic chemicals that can be recycled via plants
- release nutrients locked up in organic matter and making them available again
20
Q
S-shaped growth curve
A
- when resources are limited
- exponential growth only possible for a short period of time, resources depleted
- growth rate slows and plateaus
21
Q
photosynthesis
A
- green plants take light energy and turn it into chemical energy
carbon dioxide + water = LIGHT = glucose and oxygen
22
Q
respiration
A
- photosynthesis is reversed in respiration
- chemical energy transformed into kinetic, some lost as heat
- at a cellular level
glucose + oxygen = OXIDATION = carbon dioxide + water + energy
23
Q
trophic level
A
- position an organism occupies in the food chain
24
Q
1st law thermodynamics
A
- energy is neither created nor destroyed
25
2nd law thermodynamics
- as energy passes along the food chain entropy increased
26
calculate food chain efficiency
output/input x 100 =
eg
solar energy = 21,000
primary producers = 3,330
3,330/21,000 x 100 = 15.9%
27
ecological pyramids
- organisms at each tropic level in order
| - numbers, biomass, energy
28
pyramid of numbers
- shows number of organisms at each tropic level in the food chain
- may not be pyramid shaped, ignores biomass and energy
- 1 oak tree = 1 caterpillar
- non destructive
- good for comparing changes over time
- ignores size
- hard to represent numbers accurately
29
pyramid of biomass
- amount of biomass at each trophic level
- biomass = total amount of living matter in a given area
- measured as dry weight
- overcome the problem of counting
- destructive, unethical
- whole body is measured, including parts not contributing energy, skeleton
- extrapolated samples, inaccuracy
- seasonal variation
- animals different fat, higher fat higher energy
30
pyramid of productivity
- turnover of biomass at each trophic level
- each bar represents amount of energy generated and available for food for next level
- most accurate
- ecosystems can be compared
- solar input can be added
- data collection is not easy, need to know rate of biomass production over time
- difficult to assign trophic level to species, species can be multiple trophic levels
31
length of food chains
- terrestrial shorter than aquatic
- aquatic start smaller organisms at the base
- less biomass taken up with skeletons, more energy passed on
32
bioaccumulation
- increase in the concentration of a pollutant in an organism as it absorbs or it ingests it from its environment
33
biomagnification
- increase in the concentration of the pollutant as it moves up through the food chain
34
case study
| DDT released into an aquatic environment
- persistent organic pollutant (POP)
- stored in fat cells
- fat soluble toxins can't be eliminated through sweating or urine so they stay in the body for a long time
- half life of 15 years, stays in the environment for a long time
- results in bioaccumulation and biomagnification
- sprayed on land to control mosquitoes, ends up in nearby bodies of water
- primary producers absorb and accumulate DDT and other toxins
- herbivores ingest and accumulate the DDT from their food source
- up the food chain more and more DDT
35
apex predators in trouble
- apex predator most impacted
- amount of biomass and energy decreases up the food chain, top predators have less available food
- animal lower down food chain killed, knock on effect, impact top food chain
- dangerous levels of toxins due to biomagnification
36
solar radiation
- also called insolation
37
solar radiation to earth
| most to least
- absorbed at the surface
- reflected by clouds
- absorbed by atmosphere
- reflected by atmosphere
- reflected by earth
38
reflectivity of a surface
- albedo
| - dark colors low, light colors high
39
Biomass
- mass of living organisms in a given area expressed as dry weight of mass per unit of area or g m–2.
40
Productivity
- conversion of energy into biomass in a given time expressed as J m-2 yr-1.
- rate of growth of plants and animals in the ecosystem
- how much output you get from your input
41
Gross
- total amount of products/money made
| - total amount of biomass that is made
42
Net
- what is left over after losses
| - ecosystem losses include respiration and fecal loss
43
Primary
plants
44
Secondary
animals
45
net primary productivity
gross primary productivity - respiratory losses
46
gross secondary productivity
food eaten - fecal loss
47
net secondary productivity
gross secondary productivity - respiratory losses
48
sustainable yield
- if extracting biomass without reducing natural capital, then you are taking the net primary/secondary productivity of the system
49
productivity over time
- less productive in cold seasons
- life stages, younger organisms grow more
- introduction of disease or pests
- damage to organisms from fire etc
50
energy pathways
- solar energy enters in the form of light
- plants photosynthesize and turn light energy into biomass
- biomass is a store of chemical energy and converts from one trophic level to the next
- primary producer biomass converted into biomass of secondary producers
- these transfers are inefficient, lost as heat
51
energy __
flows
| - moves steadily and continuously in one direction
52
matter __
cycles
| - repeats itself
53
the carbon cycle stores
- atmosphere
- terrestrial plants and food
- soil and organic matter
- coal, oil, gas
- rocks
- deep ocean
54
the carbon cycle flows
- respiration
- photosynthesis
- decay
- combustion
- decomposition
55
the nitrogen cycle stores
- atmosphere
- soil organic matter
- ocean
- terrestrial plant biomass
56
the nitrogen cycle flows
- nitrifying/denitrifying bacteria
- nitrification
- ammonification
- assimilation
57
the nitrogen cycle and human activity
- fossil fuel combustion and forest fires increase nitrogen, contributes to acid rain and photochemical smog
- draining wetlands for urban expansion, denitrification happens in wetlands, less nitrogen enters the atmosphere
- use of inorganic fertilizers , takes nitrogen from the atmosphere supplementing natural fixation rates
- application of inorganic fertilizers increases denitrification and leaching, eutrophication
- farming, increased ammonia in soil animal waste, leach into nearby aquatic systems
