Chapter 20 (Ecology) Flashcards
1
Q
Definition of habitat
A
The place an organism lives
2
Q
Definition of niche
A
The role of an organism within its habitat
3
Q
Definition of species
A
A group of organisms that can interbreed to produce fertile offspring.
4
Q
Definition of population
A
Individuals of the same species living together in a given time period and defined space.
5
Q
Definition of community
A
Populations (of different species) that interact with each other in a given time period and defined space.
6
Q
Definition of autotroph
A
A species that is able to produce its own food ( usually through photosynthesis)
7
Q
Definition of producer
A
An autotroph
8
Q
Definition of heterotroph
A
A species that feeds on plant or animal material (cannot make its own food)
9
Q
Definition of consumer
A
A heterotroph that feeds on other animals or plants by ingesting them.
10
Q
Definition of herbivore
A
Only eats plant material
11
Q
Definition of carnivore
A
Only eats animal material
12
Q
Definition of omnivore
A
Eats both plant and animal material
13
Q
Definition of detritivore
A
A heterotroph that obtains nutrients by ingesting detritus
14
Q
Definition of Saprotroph
A
A heterotroph that obtains nutrients by externally digesting dead organisms
15
Q
Definition of abiotic factor
A
A non living factor within an ecosystem. ( temp, pH, salinity, light/oxygen levels)
16
Q
Definition of biotic factor
A
A living factor within an ecosystem ( predators, prey, parasites, pathogens)
17
Q
Definition of an ecosystem
A
A dynamic system consisting of all the interactions between all living organisms in a specific area and all the abiotic factors.
18
Q
Definition of overfishing
A
The removal of a species of fish from a body of water at a rate that the species cannot replenish
19
Q
Factors affecting fish population
A
- Food availability
- Level of predation
- Diseases and parasites
- Intensity of fishing
20
Q
Why are fish populations decreasing
A
- Use of drift nets
- Sonar and satellite detection means fishing is more successful
- Fleet vessels can stay out fishing for longer
- Increased operational radius of the boats
- Fish are processed at sea
21
Q
Info on fish
A
- High in protein
- Are ectotherms ( rely on external sources of heat to regulate own body temperatures)
- Hence use less energy to generate heat
- This Increases efficiency of energy transfer in their food chains
22
Q
Strategies to reduce overfishing
A
Catch Quotas Minimum catchable size Fishing effort limits No take zones Closed seasons Protected individuals Population seeding
23
Q
Info on population seeding
A
Mortality rate in captivity is lower than in the wild, so young fish are raised in captivity then released later to increase survival chances.
24
Q
Info on protected individuals
A
Some individuals are protected as they are good breeding animals. If caught, must be released.
25
Info on closed seasons
A ban on fishing for part of the year (especially during breeding season)
26
Info on No Take Zones
A complete fishing ban in part of area so a breeding population can develop.
27
Info on Fishing effort limits
Limits set on size of nets, boats or engines, or number of days fishing to reduce catch.
28
Info on Minimum catchable size
The size of net controls minimum size of fish that can be caught. (eg, small fish can escape)
29
Info on Catch quotas
Limit on total weight of fish that can be landed. Rest have to be returned.
Yet, many of them are dead before returned
30
Definition of sustainable fishing
Removing a controlled number of fish from their populations, so there are sufficient left to reproduce and replenish population, so a similar amount can be fished the following year, and year after, without significantly reducing the population size
31
Definition of Ruminants
Animals that digest plant material slowly in specialised stomachs, and regurgitate the food to chew again.
32
Examples of ruminants
Sheep
Cow/Cattle
Goats
33
Explain why 'a cow has 4 stomachs' is incorrect
The stomach is a single organ divided into 4 chambers, linked consecutively, each specialised for their specific function.
34
What are the 4 chambers in a cow's stomach.
Rumen
Reticulum
Omasum
Abomasum
Ru Re O A
Are u ready or asleep.
35
Identify the chambers in a cow's stomach.
Diagram
36
Features of the digestive system of a ruminant that allow the efficient digestion of plant material
- Rumen contains micro-organisms that produce cellulase.
- Micro-organisms in rumen and reticulum hydrolyse cellulose and other complex carbohydrates into mono- & di-saccharides.
- Other bacteria convert saccharides into fatty acids.
- Abomasum secretes HCI & proteases to hydrolyse bacterial proteins.
37
Rumen info
Conditions are anaerobic as micro-organisms in rumen respire anaerobically
38
Function of the reticulum in a cow?
- fermented grass is passed to reticulum
- it is formed into 'balls' called cud.
- cud is regurgitated to mouth to be ground further and reswallowed.
39
Function of mouth
-Grass is ground by molars + premolars, mixed with saliva, swallowed + passed to rumen.
40
Function of omasum
- Reswallowed food passed to omasum.
- Has very muscular walls
- When walls contract, it squeezes water out
- Water from cud is reabsorbed .
41
Function of Abomasum
-Cud passes to abomasum
-Digestion occurs
-Secretion of proteases +HCI
Hydrolysis of proteins into aa.
42
Function of duodenum
Chyme passes to duodenum
| Small soluble nutrients are absorbed
43
Definition of succession
A natural change in species composition of a community in a given area over a given period of time. Involves recognisable seres
Progresses to a climax community
44
Definition of a sere
A recognisable stage of succession.
45
Primary succession info
Must start from previously uncolonised land.
| biomass increases during succession
46
Secondary succession
occurs on land that has been previously colonised but vegetation destroyed.
47
Limitations in pyramids of number and pyramids of biomass
- Only represents data for snapshot in time
| - Inverted pyramids can be produced
48
Definition of productivity
The rate of energy flow
49
Definition of Gross primary productivity
The rate that producers convert light energy into chemical potential energy
50
Definition of Net primary productivity
The rate at which plants accumulate dry mass per unit area per year
51
NPP equation
GPP - R ( respiration loss)
| MAKE SURE UNITS ARE SAME
52
What happens to the glucose produced in photosynthesis.
1. Used for growth, maintenance and reproduction. with energy being lost as heat during respiration.
2. Rest is deposited in and around cells.
53
Definition of biomass
The accumulation of dry mass
54
Why increase NPP
- Increase crop yield
- Reduce energy loss
- Make energy conversion more efficient
55
Ways of manipulating primary productivity
Light
Temperature
Water
Nutrients
Competition
Fungal Disease
Pests
56
How to increase light levels
- Plant earlier in season (ensures maximum leaf exposure for PHS)
- Grow under UV Light (ensures constant, optimal light intensity & duration)
- Appropriate sowing density (prevent over-shadowing from other plants)
- Greenhouse (warm temp)
57
How to increase water availability
- Irrigation system (ensures sufficient water delivery)
| - Drought-resistant species ( inc survival if drought)
58
How to increase temp
-Paraffin heaters (emits heat & CO2 to inc rate of PHS)
59
how to inc nutrients
- Crop rotation (allows different crops to be grown --> soil nutrients to replenish)
- Nitrogen-fixing crop (Inc nitrate levels in soil)
- Use inorganic fertilisers (to inc nitrate, phosphate + potassium levels in soil)
60
How to reduce pests
- Pesticides ( kill pests which can cause disease + reduce productivity)
- Select pest-resistant species (prevent plant damage)
- select GM crop resistant to pesticide ( enables crop to be treated with pesticide but not harmed by it)
61
How to reduce fungal disease
- Fungicides ( kill fungal pathogens)
- Select fungal-resistant species (prevent plant damage)
- Select GM crop resistant to fungicide (enables crop to be treated with fungicide but not harmed by it)
62
How to reduce competition from weeds
- Apply herbicide (kills unwanted plants which reduces competition for light, space & nutrients)
- Select GM crop resistant to herbicide (enables crop to be treated with herbicide but not harmed by it)
63
Definition of secondary productivity
The rate at which animals convert the chemical energy in the plants that they consume into their own biomass.
64
Why is energy lost between producers and primary consumers
- Some plants die before they are consumed
- Not all of the plant is ingested eg, roots, thorns
- Some parts are indigestible eg, cellulose
- Some plant matter egested in faeces
- Some energy used by primary consumer for movement etc.
65
Methods used to manipulate the environment to increase the transfer between producer and primary consumer
SAIMSY
- Treat then with STERIODS --> inc growth rate
- ANTIBIOTICS --> reduce energy losses of reducing bacterial infections.
- Keep animals INDOORS--> reduce energy loss in thermoregulation --> more available for growth
- Limit MOVEMENT to reduce energy loss (Zero Grazing)
- SELECTIVE BREEDING --> produce breeds with faster growth rate + inc productivity
- Harvest animals at YOUNG AGE --> Larger proportion of energy used for growth than adults --> minimises energy losses from food chain
Concern - animal welfare vs efficient food production
66
Explain why less than 5% of sunlight is converted into chemical energy by plants.
-Light does not reach plant
-Light hits a non-photosynthesising part of the plant
-Light is absorbed by cloud cover
-Light is reflected from the leaf surface
Light heats the water on the plant
-Light passes through leaf and not captured by chlorophyll
-Light is of wrong wavelength
67
Why are hedgerows being removed
- Easier to use larger farm machinery
- amalgamation of farms
- Inc area for growing crops
- less maintenance so cheaper
- space for houses, motorways
68
Importance of hedgerows to wildlife
- Provide habitats + nesting sites
- Provide food sources
- Increase biodiversity
- Provide shelter + protection for wildlife
- inc water retention quality of soil
69
Extensive farming info
Production of crops + livestock with limited inputs, lower labour, low costs, lower yields. No fertiliser/chemicals added.
Risk of overstocking
70
Intensive farming info
Production of crops using fertilisers + chemicals (herbicides, pesticides) with high labour + machines, high cost, high yields.
Risk of disease + stress due to over-crowding -> use of antibiotics -> antibiotic resistant bacteria.
71
Role of Environmental Stewardship Scheme
- Established in 1991
-Involved in:
Maintenance of hedgerows
Maintenance of dry stone walls
Growing crops that bear certain seeds to attract bird species + nectar to attract bees.
Creating buffer strips
72
Use of herbicides/ pesticides info
- Decreases biodiversity
-disrupts food chains
(can be blown by wind and then kill non-target species)
- They dissolve in rainwater + are washed into water courses.
- Yet, do kill unwanted weeds to promote crop growth
73
How do herbicide chemicals build up in food chains
- Too slow to biodegrade
| - Can accumulate in fat stores of organisms that ingest them
74
Use of insecticides
Decreases biodiversity + disrupts food chains.
| - lead to dec in non-target species pop.
75
2 common sources of water pollution
- untreated sewage
| - over application of fertilisers (rich in nitrates & phosphates)
76
Eutrophication steps
- Nitrate + Phosphate rich fertilisers dissolve in water
- They are leached from the soil into water courses
- Excessive build up of nutrients in water courses
- Inc algal blooms due to inc nutrients, which block light rays reaching aquatic plants
- PHS rate dec --> plant death.
- Inc. dead organic matter inc food for aerobic decomposers --> more decomposers.
- Dissolved oxygen content of water dec due to inc aerobic respiration of decomposers.
- B.O.D not met --> death of other aquatic life. ( stagnant water)
77
Definition of eutrophication
| CHECK
excessive richness of nutrients in a body of water, due to run-off from the land, which causes a dense growth of plants
78
Definition of BOD
Biochemical oxygen demand
The quantity of dissolved oxygen needed by aerobic organisms to sustain life at a specified temperature for a given period of time
79
Definition of biodiversity
The variety of pant & animal life in a particular habitat/ecosystem at a genetic, individual species, and ecosystem level.
80
Definition of quadrat
Frame used to define a sampling area when measuring the distribution & population numbers or organisms.
81
Advantages of using quadrats
Keeps the sample area constant
Allows comparison between sites
Generates valid results
82
Types of quadrat
Frame
Grid
Point
83
Principles to consider when designing a sampling method
Large sample size
- > Ensure data is representative of whole ecosystem
- > more accurate + inc validity
Manpower & cost implications
Random sampling
-> avoid bias
-> inc validity
Assumption that populations in ecosystem are normally distributed.
84
Types of sampling
Systematic
Random
Stratified
85
What are transects
- To collect large quantities of data between two points
| - used where a correlation may exist between an abiotic factor and distribution of an organism
86
Type of transects
Interrupted. (gaps between quadrants)
| Continuous. (no gaps)
87
Definition of deflected succession
Succession whose direction is altered by farming or other human activities that results in a plagioclimax not climax community
88
reasons why succession can be deflected (natural disturbances)
- Tree fall
- Wildfire
- Flooding
- Hurricanes
- Insect/ disease
- Landslides
89
Reasons why succession can be deflected ( Man- induced)
- Logging
- Mining
- Dam removal
- Warfare
- Fire
- Flooding
90
Reasons why succession can be deflected ( Man- induced)
- Logging
- Mining
- Dam removal
- Warfare
- Fire
- Flooding
91
Reasons why succession can be deflated (Agriculture)
- Crops planted
- Grazing of domesticated farm animals
- Mowing
- Removal of woodland -> increase space for agriculture
92
Reasons why succession can be deflated (Forestry)
Non-native species have been planted to meet demands of timber and fuel industries
Remaining deciduous woodlands managed by coppicing and rotation.
93
Limitations of pyramids of number
- Numbers may range widely
- Pyramid may be inverted
- different species are different sizes and therefore have different quantities of energy stored in their tissues.
94
limitations of pyramids of biomass
- Dry mass requires organisms to be killed and heated to evaporate water - time consuming and costly
- the pyramid can be inverted if there is a high turnover rate.
95
Energy efficiency equation
energy available AFTER transfer/ energy available BEFORE transfer x100
96
Role of pioneer species
Stabilise the environment
Develop the soil by increasing the humus content
Change the soil pH
97
Definition of primary succession
When an uncolonised areas becomes colonised by different communities as a result of natural change in species composition, passing through a series of recognisable seres, over a period of time until a climax community is reached.
98
Stages of succession
1. Pioneers
2. Early succession
3. Mid-succession
4. Late Succession
99
What happens in stage 1 of primary succession
Pioneers
- The initial colonisers
-Must be autotrophic and able to tolerate hostile conditions with good seed/spore dispersal mechanisms
eg, lichen, moss, small dicotyledons.
100
What happens in stage 2 of
| primary succession
Early succession
- As conditions change, different species will be able to survive
- Area is invaded by opportunists and generalists - they have good dispersal mechanisms and ability to tolerate a wide range of conditions
eg, grasses, herbs.
Further increases nitrogen fixation and humus content
101
What happens in stage 3 of primary succession
Mid-succession
Soil is now richer in humus, water, nutrients + organic matter
Small shrubs start to appear
greatest biodiversity occurs here.
102
What happens in stage 4 of primary succession
Soil is deeper and more fertile
small trees inhabit area
species with larger biomass + larger root systems appear
103
When is a climax community reached
The final sere in succession
| - when the community is in equilibrium with the environment
104
What happens in the rumen
-Anaerobic conditions
- bacteria produce cellulose and hydrolyse cellulose to beta glucose by breaking. glycosidic bonds
sugars are fermented to organic acids, which are then absorbed into plasma.
Sugars converted to fatty acids, carboxylic acids, ethanoic acid
Waste products ( CO2, H20 vapour, CH4)
Bacteria in rumen produce proteins and synthesise vitamins for the ruminant.
105
Energy flow through an ecosystem
Sun -> producer -> primary consumer -> secondary consumer -> tertiary consumer
106
energy flow information
. All energy within ecosystems originates from sun
. Photosynthesis converts light energy to chemical potential, using photoautotrophs.
. Chemical potential energy stored as carbohydrates, lipids, proteins in plants
. herbivores digest, and absorb nutrients from plant material
. CPE is passed to CPE in consumers
. in plants and animals, energy is released from energy storage molecules via respiration, which produces ATP.
. ATP is then hydrolysed to release energy
107
Which metabolic reactions can energy be used for
Active Transport
Cell Growth
Cell Division
Maintenance of body temperature
macromolecule synthesis, eg, nucleic acids, lipids, proteins
Bulk transport, exocytosis, endocytosis
108
Definition of trophic level
Feeding level, position in food chain
| source of food, energy
109
Definition of plagioclimax?
A stable plant community that has arisen as a result of human intervention in the natural succession of communities.
