B4.1 - Ecosystems Flashcards
(94 cards)
1
Q
What is the definition of an ecosystem
A
An ecosystem is made up of all of the living organisms and physical conditions present in an area
2
Q
What is a community?
A
All the living organisms in an area
3
Q
What is a habitat?
A
The place in which an organism lives
4
Q
What is the population?
A
The number of organisms of a species living in an area
5
Q
What are the main three groups/categories of a community?
A
Producers
Consumers
Decomposers
6
Q
What is a producer
A
An organism that can make its own food by photosynthesis
7
Q
What are examples of producers?
A
Plants
Algae
8
Q
What are consumers
A
Organisms that cannot make their own food. They have to eat other organisms to gain energy
9
Q
What are examples of consumers
A
All animals are consumers
10
Q
What are decomposers?
A
A special group of consumers.
They gain their energy by feeding on dead or decaying material
11
Q
What is biomass
A
The total mass of organism in a given area
The mass of living material present
12
Q
How is energy transferred in a producer
A
Energy from the sun is transferred by light to chlorophyll in plant cells
Here carbon dioxide and water react to produce glucose which stores energy within its chemical bonds.
Glucose can then be converted into carbohydrates, fats and proteins which are used as energy stores for growth and repair.
As an organism grows it increases its biomass
13
Q
Where does glucose store its energy
A
Within its chemical bonds
14
Q
What can glucose be converted to
A
Carbohydrates
Fats
Proteins
15
Q
How is energy transferred in consumers
A
Consumers eat the producers.
When the organism respires, the energy stored in its food is transferred to make ATP.
The organism grows and its biomass increases
16
Q
What is a food chain?
A
It displays what an organism eats
17
Q
What do the arrows in a food chain represent?
A
They show the transfer of biomass from one organism to the next .
18
Q
What is a trophic level?
A
It is a feeding level in a food chain
Each step in a food chain is a trophic level
19
Q
What is a prey organism
A
An animal that is eaten by another animal
20
Q
What is a predator organism
A
An animal that eats other animals
21
Q
What are herbivores and what trophic level are they at
A
Herbivores are animals that only eat plants
They are primary consumers
22
Q
What is a carnivore and what level is it at in the food chain
A
A carnivore is An animal that only eats other animals
They are secondary consumers
23
Q
What are tertiary consumers
A
They eat secondary consumers
24
Q
What is a food web?
A
It is a series of interlinked food chains
25
What are the 2 main factors that affect an ecosystem?
Biotic factors
Abiotic factors
26
What is a biotic factor?
These are living factors
27
What are abiotic factors?
These are non-living or physical factors
28
What are examples of biotic factors
Competition
Number of organisms
Predation
Parasitism
Mutualism
29
What are examples of abiotic factors?
Temperature
Light intensity
Moisture levels
Soil pH
Level of pollutants in the air
30
How does light intensity affect communities?
Light is required for photosynthesis .
The greater the light intensity, the greater the success of a plant.
Plants evolve to grow successfully in different light intestities
31
How does temperature affect communities
Temperature effects enzymes that control metabolic reactions.
Plants develop faster in warmer temperatures as their metabolic rate would be faster.
Cold blooded animals rely on the sun to warm them up
32
What are ectotherms?
Cold blooded animals
33
What are endotherms
Warm blooded animals
34
How does moisture levels affect communities
A lack of water can lead to death
A lack of water causes plants to wilt because water is required to keep their cells turgid
Water is also required for photosynthesis
For animals:
Water is the main component of blood plasma
35
How does soil pH affect communities?
The pH of soil affects the availability of certain minerals
36
What plants grow better is acidic soils
Ferns
Rhododendrons
37
What plants grow better in alkaline solutions
Cucumbers
Cauliflower
38
What sensor is used to measure light intensity
A light meter
39
What sensor is used to measure the availability of moisture
Humidity sensor
40
What sensor is used to measure pH
A pH probe
41
What is competition?
Two or more organisms contesting a resource
42
Why do organisms need to compete?
To survive, animals and plants need a number of different minerals from their surroundings.
If materials are limited, plants and animals may need to compete for resources
43
What do plants need to survive?
Light
Water
Carbon dioxide
Minerals
Space
44
What do animals need to survive?
Food
Water
Breeding partners
Space (territory)
Shelter
45
How does competition affect the size of a population
Competition has a direct effect on the size of a population
If there is a large amount of food available the population would increase
46
What is interdependence
How different organisms depend on each other within a community
47
What is an ecological relationship
Interactions between organisms in their environment
48
What are the three main types of ecological relationships
Predation
Mutualism
Parasitism
49
What is predation
The relationship between predator and prey organisms.
Predators depend of prey for food.
The size of the predator population directly affects the size of the prey population
50
What is mutualism
A relationship where both organisms benefit
51
What is parasitism?
Relationship in which The parasite gains and the host is harmed
52
What is an example of a mutualistic relationship
Oxpeckers that live on Buffalo eat ticks and fleas living on the Buffalos skin.
The oxpeckers gain food while the Buffalo is free from irritation and potential disease
53
What are examples of a parasitic relationship
Tapeworms in an animals digestive system
Fleas on cats
54
What are disadvantages of food chains
They don’t show :
the number of organisms involved
the size of biomass transferred
55
What does a pyramid of number show
It shows the population at each trophic level
56
What does the bar width on a pyramid of number represent
It represents the number of organisms present
57
Why are pyramid of numbers USUALLY pyramid shaped
One organism usually eats several organisms from the trophic level below
As you move from one trophic level to the next:
the size of the organism generally increases
The number of organisms generally decreases
58
Why are not all pyramids of number pyramid shaped? (Why are some inverted)
Because pyramids of numbers do not take into account The size of the organism present
59
What are disadvantages of pyramids of numbers
They don’t take into account the size of the organism present
60
What are pyramids of biomass
It is a diagram representing the amount of biomass present at each trophic level of a food chain
61
What is are advantages of pyramids of biomass
They take into account the number and size of the organism present
62
How do scientists calculate biomass
They measure the average mass of organisms from each trophic level and multiply it by the number of organisms present at each trophic level
63
Why do scientists calculate dry mass
Water content can vary between individuals
64
How do scientists calculate dry mass
The organism has to be killed and dried in a kiln
65
How is energy transferred to producers
By sunlight
66
How much of the energy from sunlight to producers transfer to their chemical stores
Around 1%
67
What happens to most of the energy transferred by sunlight
Most of the light is reflected from the leaf
68
What happens to the energy transferred by photosynthesis
Up to half of it is used in respiration
The rest is transferred to increase the plants biomass
69
How much energy from food to consumers convert into new body tissue
10%
70
How is biomass lost
Eating
Respiration
Egestion
Excretion
71
How is biomass lost through eating?
Not all of an organism is eaten (e.g bones)
72
How is biomass lost through respiration
Respiration causes thermal energy to transfer to the surroundings
73
What is egestion
The removal of indigestion waste from an organism
74
Why is biomass lost through egestion
Parts of an organism that cannot be digested (e.g hair) are removed from the body in faeces
75
How is biomass lost through excretion
Waste products are lost through excretion
76
Why do very few food chains have more than 4 trophic levels
At each stage of the food chain the amount of energy becomes less
So not enough energy can be transferred to sustain life processes
77
How do you calculate the efficiency of biomass transfer?
Efficiency of biomass (%)=
Biomass available after (g)
——————————————
Biomass available before(g)
78
How is CO2 removed from the atmosphere
Carbon dioxide is removed from the environment during photosynthesis
Carbon dioxide and water are converted into glucose and oxygen
The glucose is converted into carbohydrates fats and proteins.
The carbon is apart of their extra biomass
79
What happens to the carbon in the plant when the plant is eaten by an animal
The carbon in the plant is transferred to the animal
Some of this carbon is used to produce fats and proteins in the animals body
80
How is carbon released back into the environment
Respiration
Decomposition
Burning fossil fuels
81
How do respiration and decomposition release CO2 back into the environment
Carbon dioxide is a product of respiration
Decomposers break down the remains of dead organisms, releasing co2 as they respire
82
How does burning fossil fuels release co2 back into the atmosphere
Fossil fuels are a store of carbon
When they burn, this trapped carbon is released
83
What are examples of fossil fuels
Coal
Oil
Natural gas
84
What is a decomposer?
Organisms that gain their energy by feeding on dead or decaying material
85
What is a detritivore
They are small animals which break down organic material into smaller pieces
86
What do decomposers do?
They break down dead organic material at a microscopic level
They also break down animal waste
Through decomposition, nutrients are released which can then be recycled
87
Wha do detritivores do?
They speed up decomposition by shredding organic material into very small pieces
This creates a larger surface area for decomposers to work on
88
How do decomposers release nutrients?
The decomposer secretes enzyme on to the dead remains
The enzymes digest the dead matter and make it soluble
The soluble products are absorbed by the decomposer
89
What factors do microorganisms decompose materials most efficiently in?
Warm temperatures
Moist environment
Aerobic conditions
90
How does temperature affect the rate of decomposition
At high temperatures the enzymes denature. This prevents decomposition and can result in the death of the microorganism
At low temperatures the rate of decomposition is too slow as the rate of enzyme reaction is decreased. The rate of microorganism replication is also low
91
How do water levels affect the rate of decomposition
If not enough water is available the reactions within the microorganism will slow down
This reduces or stops decomposition
92
How does oxygen levels affect the rate of decomposition
Oxygen is needed for the microorganism to respire
Anaerobic conditions will prevent decomposition as the microorganism cannot survive in this environment
93
How do you calculate the rate of decay
Rate of decay (g/day) = change in mass (g)
———————————
Time (day)
94
Explain the nitrogen cycle
- Organisms use nitrogen to make DNA and proteins
- Nitrogen exists in the soil as nitrates dissolved in water
- The water is taken into the roots and the nitrates are used to make proteins
- When the plant is eaten, nitrogen compounds are passed on to an animal
- When plants and animals die, these compounds are broken down and released into the soil and ammonia
- Animals also put nitrogen back into the soil in faeces and urea
- Some plants (e.g peas) form mutualistic relationships with nitrogen fixing bacteria which live in their roots and combine nitrogen from the air with oxygen to form nitrates. These are then used by the plant
