P2 16/17/18 Ecology Flashcards
(42 cards)
1
Q
define organism and habitat
A
organism - individual living thing
habitat - place where organisms live
2
Q
define community
A
all of the living things in an ecosystem
3
Q
define population
A
all organisms of any one specie living in a habitat
4
Q
define ecosystem
A
a community of living organisms interacting with biotic and abiotic factors
5
Q
describe how a change in biotic+abiotic factors may affect a community
A
cause an imbalance in organism populations -> unstable community
* direct effects eg. introduction of a new predator leads to a decrease in the prey population
* indirect effects eg. other organisms relying on the prey (for food etc) -> more population decline
6
Q
name biotic factors in an ecosystem (4)
A
- predators/prey
- availability of food (animals+plants)
- competing species (interspecific competition)
- diseases (pathogens)
7
Q
describe how a biotic factor may affect plants and animals (4)
A
- new predators: decrease in prey population, then reduces food left for existing predators
- availability of food: areas with rich food supply (rainforest) have more species/life than desert/tundra
- competing species: natural selection
- diseases: wipes out an entire specie
8
Q
name abiotic factors in an ecosystem (6)
A
light intensity, temperature, moisture levels, oxygen/CO2 levels, wind intensity/direction, soil pH / mineral content
9
Q
describe how a change in an abiotic factor may affect plants and animals (6)
A
- (low) light intensity: less photosynthesis so plants have less energy+ grow slower, animals sleep longer as they think it’s night
- (high) temp: more transpiration so less water for photosynthesis, more sweating leads to dehydration
- (low) moisture levels: less water for photosynthesis so slow growth
- (not optimum) pH: plants cannot grow
- (high) wind intensity: more transpiration so less water for photosynthesis, cooler temp for animals
- (low) O2+CO2 levels: less gases available, needed for respiration/photosynthesis
10
Q
define interdependence
A
- organisms depend on each other for survival
- a change in a biotic/abiotic factor will affect the abundance and distribution of organisms in an ecosystem
11
Q
describe a stable community
A
- all biotic and abiotic factors are balanced
- so population size remains (fairly) constant
- high level of interdependence
12
Q
what do animals compete for in an ecosystem
A
food, water, territory/space, mates
13
Q
what do plants compete for in an ecosystem
A
light, water, space, nutrients (minerals)
14
Q
why do animals+plants compete for resources in an ecosystem
A
we have a set amount of resources on earth that are constantly recycled (carbon/water cycle)
15
Q
define extremophile
A
organisms that are highly specialised/adapted to live in extreme conditions, eg. high temp (thermophile - bacteria) or high salt concentration (halophile)
16
Q
name structural (physical features) adaptations
A
- plants in hot climates reduce surface area (cacti spines) and increase spread of roots - prevents water loss by transpiration
- herbivores have teeth adapted to grind plants, whereas carnivores have sharp teeth to slice meat
- animals in cold climates have thick, fatty bodies to lower SA:V - reduces heat loss
–> conversely animals in hot climates have thin limbs+bodies to help lose heat by increasing SA:V
17
Q
name functional (bodily processes) adaptations
A
- snakes+spiders produce poisonous venom - protection against predators and immoblises prey
- plants in hot climates store water in stem - prevents water loss
- camouflage - benefits predators and prey
18
Q
name behavioural (learned/inborn) adaptations
A
- polar bears dig deep dens in snow - protects themselves from strong winds and keeps warm
- animals attract mates to reproduce
19
Q
describe the role of photosynthetic organisms
A
- they are producers - produce their own food using light energy+ inorganic materials through photosynthesis
- they create biomass which provides energy for other life processes - this is consumed by consumers
- green plants and algae
20
Q
describe what a food chain shows
A
the direct transfer of energy between organisms in an ecosystem:
(the Sun ->) producers -> primary consumers -> secondary consumers -> tertiary consumers -> decomposers
21
Q
describe the relationship between predators and prey
A
- in stable communities, the number of predators+prey rise/fall in continuous cycles
1. increase in prey causes an increase in predators as there is enough food to support them
however predators will increase, therefore decreasing prey as more will need a source of food
2. decrease in prey causes a decrease in predators as there is a food deficit
this means there will be more prey as they can survive longer due to less predators
22
Q
describe the processes which cycle carbon (4)
A
- combustion: CO2 released when fossil fuels are burned
- respiration: CO2 released by animals
- decay: CO2 released when organic matter decomposes
- photosynthesis: CO2 converted into glucose (containing carbon) and oxygen
23
Q
describe the carbon cycle from the stage where CO2 is released (3)
A
- extracted fossils are combusted to produce energy which releases CO2 // animals respire which releases CO2 (from glucose) and energy+water
- CO2 is taken in by plants for photosynthesis, which converts CO2+water into glucose (containing carbon)+oxygen // CO2 enters animals who feed on plants
- plants+animals die (becoming organic matter) and decompose, which releases CO2, methane, water/minerals and energy
24
Q
describe the role of microorganisms in the carbon cycle
A
eg. bacteria/fungi
they decay plant+animal remains, then return the carbon in them to the atmosphere through respiration
also release minerals back into the soil which enters plant roots
25
describe the water cycle from evaporation (5)
* water in oceans/rivers/lakes evaporates and water in green plants transpires, which turns into water vapour
* water vapour cools+condenses into clouds as it rises
* water in clouds falls as precipitation
* freshwater consumed by plants+animals on land
* water runs back into the sea through surface run-off and groundwater flow
26
define biodiversity
a measure of the variety of living organisms within a particular area
(number of different species and number of individuals of each specie)
27
why is biodiversity important
* makes ecosystems more stable
* the more species there are, the less dependent each specie is on another (for food/shelter) as there are alternatives
28
describe the cause+impact of human population growth on biodiversity
improved healthcare leads to population growth and increased standard of living, so more resources used and more waste created, so habitats destroyed
29
name human activities affecting biodiversity (3)
* waste management - water/air/land pollution
* land use
* deforestation
30
describe impact of waste management on 3 types of pollution
* water pollution: toxic chemicals/ sewage/ fertilisers from industry+agriculture damages marine ecosystems
* air pollution: burning of fossil fuels for energy increases amount of greenhouse gases in atmosphere, extreme temp+weather
* land pollution: contaminates water supplies, landfill destroys habitats, releases greenhouses gases at incineration
31
describe impact of human land use +example
* more land used for building/ farming/ mining/ landfill as population grows
* reduces amount of land available for animals+ plants to grow, destroys existing habitats, soil no longer fertile
* eg. peat bogs are a specialised habitat, species are adapted to the moist/acidic environment - peat is removed for garden compost+ fuel - destroys habitat+ releases carbon dioxide
32
describe the impact of destroying peat bogs
* peat bogs are a specialised habitat - species that live there are adapted to the moist/acidic environment
* peat is removed for garden compost+ fuel
* destroys habitat for variety of animals+plants - reduces biodiversity
* also decay/burning of peat releases CO2 - impacts global warming
33
describe causes of deforestation (6)
* LOGGING: trees felled to harvest timber for profit
* MINING: forests cleared for open-cast mines, valuable minerals/metals
* (HEP) ENERGY DEVELOPMENT large areas of forest flooded for dams/reservoirs, displaces plants+animals
* FARMING: space for crops/ livestock, eg. palm oil in rainforests, biofuel
* ROAD BUILDING: built to bring in equipment+ bring products out, access to logging sites
* SETTLEMENT/ POPULATION GROWTH: trees cleared to make room for settlements to provide for growing population
34
describe impact of deforestation on the environment (3)
* increased CO2 levels - less photosynthesis - rising global temperatures
* less transpiration - nutrients in soil become leached
* **reduces biodiversity** - plants/animals die due to lack of food+shelter
35
describe the greenhouse effect
* naturally occuring
* insulates the earth - keeps it warm enough (at 15 degrees) to sustain life
* most of the Sun's solar energy is absorbed by the earth's surface and some is reflected into the atmosphere
* some reflected energy passes through atmosphere+ into space, but some is trapped by greenhouse gases (CO2/ methane) in atmosphere
36
describe human activities impacting global warming (3)
* burning of fossil fuels to generate energy - releases CO2 into atmosphere
* agriculture (livestock+ rice farming) - methane released by animals during digestion and by the decomposition of organic matter in flooded rice fields
* deforestation: less trees so less CO2 removed from atmosphere
37
describe biological consequences of global warming
* ice caps melting - loss of polar habitats
* land ice melting - rising sea levels - flooding/submersion of areas destroys habitats, threatens low-lying cities
* rising sea temp - extinct marine species as not adapted
* extreme weather conditions in some areas - mass migration - overpopulation/ unstable communities
* drought - food+water shortages
38
describe human efforts made to reduce their impact on biodiversity/ecosystems (5)
* BREEDING PROGRAMMES: aim to breed endangered species in protected conditions+ release back into the wild
* PROTECTION/REGENERATION: endangered habitats protected by laws/regulations and made into nature reserves/ national parks, allows trees to grow
* REINTRODUCING HEDGEROWS: farms (with large areas of one crop) having hedgerows around fields to provide habitats for a variety of species
* REDUCE DEFORESTATION: laws preserving rainforests - lowers CO2 levels, provides habitats for various species
* RECYCLING: reduces amount of waste at landfill + extraction of new materials
39
describe steps for measuring abundance of (plant) species in a field (RP)
* choose a starting point on the field in an area where the grass is often cut
* use random numbers to generate a set of coordinates, then place your first quadrat
* count the number of different plant species within this quadrat
* return to your starting position and repeat steps two and three a further 9 times using different random coordinates
* repeat steps one to four for a part of the field which the grass is infrequently cut
* calculate how many plants total were found at each location, then use the estimate to find an estimate of the population of the entire field
40
why are quadrats used
* a sample of the population is used to estimate the population **abundance** in an ecosystem
* used to sample an area that is too big to completely survey
41
why are transects used
* line (rope/ tape measure) used to measure the population **distribution** in an ecosystem
* samples of species present are taken at regular intervals along the line
* used to sample an area that is too big to completely survey
* laid along a gradient (eg. low/high tide) to see its effect on distribution
42
define eutrophication
a body of water (lake/bog) becomes overly enriched with nutrients
leads to an overgrowth of algae+water plants
causes reduction of dissolved oxygen in water
