B4 Flashcards
(143 cards)
1
Q
What makes up an ecosystem?
A
An ecosystem includes all living organisms (community) and their physical environment (habitat).
2
Q
What is a population in an ecosystem?
A
A group of organisms of the same species living in the same area.
3
Q
What are the three main types of organisms in an ecosystem?
A
- Producers
- Consumers
- Decomposers
4
Q
What do producers do?
A
Make their own food through photosynthesis (e.g., plants, algae).
5
Q
What do consumers do?
A
Cannot make their own food; they eat other organisms.
6
Q
What don decomposers do?
A
Break down dead or decaying material to gain energy.
7
Q
How is energy transferred between organisms in an ecosystem?
A
• Energy from the Sun is absorbed by producers through photosynthesis to make glucose.
• Consumers eat producers, transferring stored energy.
• When organisms die, decomposers break them down, recycling nutrients.
8
Q
What is the ultimate source of energy for all living organisms?
A
The sun
9
Q
What does a food chain show?
A
A food chain shows the transfer of energy between organisms by feeding relationships.
10
Q
What do arrows indicate in a food chain?
A
Arrows indicate the flow of energy from one organism to the next.
11
Q
What is the trophic level 1 and 2 in a food chain?
A
Trophic level 1- Producers (e.g., plants).
Trophic level 2- Primary consumers (eg. herbivores)
12
Q
What is the trophic level 3 and 4 in a food chain?
A
Trophic level 3 – Secondary consumers (carnivores that eat herbivores).
Trophic level 4 – Tertiary consumers (top predators).
13
Q
Give an example of a food chain in a grassland.
A
Grass (Producer) → Rabbit (Primary Consumer) → Fox (Secondary Consumer).
14
Q
How is a food web different from a food chain?
A
A food web shows how different food chains interconnect in an ecosystem, demonstrating multiple feeding relationships.
15
Q
Define producer, consumer and herbivore.
A
- Producer - Make its own food
- Consumer- Eats other organisms
- Herbivore- Eats plants only
16
Q
Define carnivore, omnivore, prey and predator
A
Carnivore – Eats other animals.
Omnivore – Eats both plants and animals.
Prey – Hunted by predators.
Predator – Hunts and eats other animals.
17
Q
What happens if slugs are removed from an ecosystem?
A
It could disrupt the food web, affecting species that rely on slugs for food and those that slugs feed on, potentially causing population imbalances.
18
Q
What are the two main types of factors that affect an ecosystem?
A
- Biotic factors
- Abiotic factors
19
Q
Name some biotic factors
A
Living factors (e.g., predators, food supply, competition).
20
Q
Name some abiotic factors
A
Non-living factors (e.g., temperature, rainfall, light, pH).
21
Q
Give examples of biotic factors in a woodland ecosystem.
A
The presence of beech trees, squirrels, and hedgehogs are biotic factors. Their population sizes are also considered biotic factors.
22
Q
Give examples of abiotic factors in an ecosystem.
A
Rainfall, temperature, light intensity, soil pH, oxygen availability.
23
Q
How do abiotic factors influence species survival?
A
They determine where species can live by affecting growth, reproduction, and competition for resources.
24
Q
How does light intensity affect plant growth?
A
• Plants need light for photosynthesis.
• More light → Larger leaves for photosynthesis.
• Less light → Adaptations to absorb more light efficiently.
25
How does temperature affect organisms?
1. It affects enzyme controlled reactions (eg. metabolism)
2. Warmer temperatures speeds up enzyme activity
3. Cold-blooded animals (ectotherms) rely on external heat sources.
4. Warm-blooded animals (endotherms) regulate body temperature internally.
26
Why is water important for plants and animals?
1. Plants need water for photosynthesis.
2. Animals need water for blood plasma and body functions.
3. Lack of water leads to dehydration and death.
27
How does soil pH affect plant growth?
pH affects nutrient availability and microbial activity in soil.
1. some plants prefer acidic soils (ferns)
2. some plants prefer alkaline soils (cucumbers, cauliflowers)
28
Is oxygen availability a biotic or abiotic factor?
Abiotic, because it is a non-living factor affecting respiration and survival of organisms.
29
How might plants adapt to low-light conditions?
1. larger leaves capture more sunlight.
2. more chlorophyll for better light absorption.
3. growing taller to reach more light
30
Why do farmers test soil pH before planting?
To match crops to suitable soil conditions.
1. Some crops need acidic soil, others need alkaline soil.
2. Helps maximize crop yield and nutrient absorption.
31
What sensor do you use to measure temperature and what units used?
1. Thermometer
2. Degrees celsius
32
What sensor do you use to measure light intensity and what units used?
1. Light meter
2. Lux
33
What sensor do you use to measure soil moisture and what units used?
1. Moisture metre
2. % moisture content
34
What sensor do you use to measure soil ph and what units used?
1. Ph meter
2. Ph scale
35
How would removing a food source affect an ecosystem?
It reduces the population of consumers that rely on that food, which disrupts the food chain.
36
How do abiotic factors affect ectotherms and endotherms differently?
1. Ectotherms (cold-blooded animals) depend on external heat (e.g., lizards).
2. Endotherms (warm-blooded animals) regulate their body temperature (e.g., mammals).
37
What is competition in ecosystems?
Competition occurs when plants and animals compete for limited resources like food, water, and space. Weaker species may die or leave the area.
38
What are the essential resources plants need to survive?
Light , Water , Carbon dioxide Minerals and Space
39
Why does a plant with a large amount of space have a higher chance of survival?
It has better access to light, water, and minerals without competing with other plants.
40
What are the essential resources animals need to survive?
Food , Water, Breeding partners, Space (territory) , Shelter
41
What is a population in an ecosystem?
A population is the number of organisms of a species living in a specific area. The availability of food directly affects population size.
42
Why do animals require access to space to survive?
Space provides enough food, shelter, and breeding opportunities. Lack of space can lead to competition and decline in population.
43
What does interdependence mean in an ecosystem?
It refers to how different species depend on each other to survive.
44
What are the three main types of ecological relationships?
1. Predation
2. Mutualism
3. Parasitism
45
What is predation in an ecosystem?
Predation is the relationship between a predator and its prey, where the predator population size affects the prey population size.
46
What is mutualism in an ecosystem?
A relationship where both organisms benefit.
47
What is an example of mutualism between oxpeckers and buffaloes
Small birds (oxpeckers) live on buffalo. They gain food by eating fleas and ticks, while the buffalo benefits from pest removal.
48
What is parasitism in an ecosystem?
A relationship where one organism (parasite) benefits and the host is harmed.
49
What are two examples of parasitism?
1. Tapeworms living in animal digestive systems.
2. Fleas sucking blood from animals.
50
In the relationship between a mosquito and a human, which is the host and which is the parasite?
The mosquito is the parasite, and the human is the host.
51
Why do plants need light to survive, but animals do not?
Plants use light for photosynthesis, while animals get energy from consuming food.
52
Identify the type of ecological relationship:
1. Bees and flowers
2. Blackbirds and worms
1. Mutualism – Bees pollinate flowers while collecting nectar.
2. Predation – Blackbirds eat worms for food.
53
How can a scientist study predator-prey relationships in a lab
1. Establish a suitable predator and prey population.
2. Observe how changes in one population affect the other over time.
54
What are the nodules found on pea plant roots, and what do they do?
They contain nitrogen-fixing bacteria that convert nitrogen from the air into nitrates for the plant. In return, the plant provides sugars to the bacteria.
55
What happened when the grey squirrel was introduced to the UK?
Originally from North America, it outcompeted the native red squirrel for food and space, leading to the red squirrel’s decline.
56
What is biomass?
The total dry mass of organisms in a given area or ecosystem.
57
Why is biomass important in an ecosystem?
It shows how much energy is available at each trophic level and helps scientists understand energy flow in food chains.
58
Why do scientists measure dry mass instead of wet mass?
Water content varies between organisms, so using dry mass provides a more accurate measurement of biomass.
59
What does a pyramid of biomass represent?
It shows the total biomass present at each trophic level of a food chain.
60
What are the levels in a typical pyramid of biomass?
1. Producers (plants) – bottom level
2. Primary consumers – herbivores
3. Secondary consumers – carnivores that eat herbivores
4. Tertiary consumers – top predat
61
Why are most pyramids of biomass shaped like pyramids?
Because biomass decreases as you move up the food chain since organisms use energy for life processes, and not all energy is passed on.
62
What happens to biomass as you move up the trophic levels?
• Biomass decreases at each level.
• Organisms use energy for respiration, movement, and heat loss.
• Some parts of food are not digested or eaten
63
Can a pyramid of biomass ever be inverted?
Yes, in rare cases where a single large producer (like a tree) supports many small herbivores.
64
Give an example of an inverted pyramid of biomass.
A giant sequoia tree has a much higher biomass than the insects, birds, and fungi that feed on it.
65
How do scientists calculate biomass at each trophic level?
1. Take samples of organisms at each level.
2. Measure the average dry mass of each species.
3. Multiply by the total number of organisms in that level.
66
What type of organism is always at the base of a pyramid of biomass?
Producers (e.g., plants, algae).
67
What type of food chain could result in an inverted pyramid of biomass?
A food chain where a large producer (e.g., a tree) supports many smaller consumers.
68
What does biomass transfer efficiency measure?
The percentage of biomass passed from one trophic level to the next.
69
List three reasons why biomass decreases as you move up the food chain.
1. Not all food is eaten (e.g., bones, fur).
2. Some food is indigestible and lost as feces.
3. Energy is used for movement, respiration, and heat loss.
70
What are three main ways energy is lost between trophic levels?
1. Respiration – energy used for movement and body functions.
2. Egestion – undigested food is lost as feces.
3. Heat loss – especially in warm-blooded animals.
71
Why do mammals and birds transfer biomass less efficiently than cold-blooded animals?
They use more energy to maintain a constant body temperature, especially in cold environments.
72
Do herbivores or carnivores have a more efficient biomass transfer?
Carnivores – because they digest meat more efficiently than herbivores digest plants.
73
How do cows lose biomass before passing it to the next level?
• Egests undigested food (e.g., grass fibers).
• Excretes waste in urine.
• Uses energy for movement and heat.
• Not all of its body is eaten by humans or predators.
74
What is the formula for biomass transfer efficiency?
efficiency= (biomass transferred to next level/ total biomass at previous level) x 100
75
Why do scientists study biomass transfer?
It helps with:
• Sustainable farming
• Wildlife conservation
• Managing food chains
76
Name two factors that affect biomass transfer efficiency.
1. Diet – carnivores transfer biomass more efficiently than herbivores.
2. Metabolism – warm-blooded animals lose more biomass through heat.
77
What is nutrient cycling?
Nutrient cycling is the movement of essential elements like carbon, nitrogen, and water through the ecosystem, allowing them to be reused by organisms.
78
What role do decomposers play in nutrient cycling?
Decomposers (bacteria & fungi) break down dead organisms, releasing nutrients back into the environment for reuse by plants and animals.
79
What are biotic and abiotic components in nutrient cycling?
• Biotic: Living organisms (plants, animals, decomposers).
• Abiotic: Non-living elements (air, water, soil, minerals).
80
Why do organisms need carbon?
Carbon is essential for making carbohydrates, fats, proteins, and DNA.
81
How is carbon cycled in an ecosystem?
• Plants absorb CO₂ during photosynthesis.
• Animals eat plants, gaining carbon.
• Respiration releases CO₂ back into the air.
• Decomposers break down dead organisms, releasing CO₂.
• Combustion of fossil fuels adds more CO₂ to the atmosphere.
82
Where is carbon stored in the environment?
Carbon is stored in oceans, soil, fossil fuels, and living organisms.
83
Why do organisms need nitrogen?
Nitrogen is needed to make DNA and proteins for growth and development
84
Can plants and animals use nitrogen from the air?
No, nitrogen gas (N₂) must be converted into nitrates (NO₃⁻) for plants to absorb and use.
85
How is nitrogen gas (N₂) turned into a usable form for plants?
1. Nitrogen-fixing bacteria in soil and plant roots (convert N₂ into ammonia).
2. Lightning (converts N₂ into nitrates).
86
What is nitrification?
Nitrifying bacteria convert ammonia (NH₃) → nitrites (NO₂⁻) → nitrates (NO₃⁻), which plants absorb.
87
What is denitrification?
Denitrifying bacteria convert nitrates back into nitrogen gas (N₂), releasing it into the atmosphere.
88
How do animals get nitrogen?
By eating plants or other animals, transferring nitrogen through the food chain.
89
How does animal waste contribute to the nitrogen cycle?
Animal waste (urine & feces) returns nitrogen to the soil as ammonia, which is further broken down.
90
Why is water important for ecosystems?
Water is essential for:
• Drinking & hydration
• Transport of nutrients in organisms
• Maintaining habitats for aquatic life
91
What are the four main stages of the water cycle?
1. Evaporation
2. Condensation
3. Precipitation
4. Collection & Runoff
92
Explain evaporation in terms of the water cycle.
Sun heats water, turning it into vapor.
93
Explain condensation in terms of the water cycle.
Water vapor cools and forms clouds.
94
Explain precipitation in terms of the water cycle.
Water falls as rain, snow, or hail.
95
Explain precipitation in terms of the water cycle.
Water gathers in lakes, rivers, and oceans.
96
How do plants and animals take in water?
• Plants absorb water through their roots.
• Animals drink water or absorb it through food.
97
How does the water cycle help with nutrient movement?
Water dissolves nutrients and transports them through ecosystems (e.g., soil, rivers, plants).
98
Name one biotic and one abiotic component that contains carbon.
• Biotic: Plants (organic molecules).
• Abiotic: Carbon dioxide in the atmosphere.
99
Explain why water is essential to maintain life.
Water is needed for hydration, transporting nutrients, and chemical reactions in cells.
100
How does water move through a plant?
1. Absorbed by roots.
2. Travels up xylem.
3. Evaporates from leaves (transpiration).
101
102
Why is carbon essential for life on Earth?
Carbon is an essential element in organisms and must be constantly recycled through the Earth and its atmosphere to sustain life.
103
What is the carbon cycle?
The carbon cycle is the process by which carbon is cycled through the atmosphere, Earth, plants, and animals.
104
What are the main stages of the carbon cycle?
1. Photosynthesis
2. Consumption
3. Respiration
4. Decomposition
5. Combustion
105
What happens in the photosynthesis part of the carbon cycle?
Plants absorb carbon dioxide (CO₂) from the atmosphere.
106
What happens in the consumption part of carbon cycle?
Animals eat plants, transferring carbon to their bodies.
107
What happens in the respiration part of carbon cycle?
Both plants and animals release CO₂ back into the atmosphere
108
What happens in the decomposition part of carbon cycle?
When organisms die, decomposers release carbon back into the atmosphere.
109
What happens in the combustion part of carbon cycle?
Fossil fuels, when burned, release CO₂ into the atmosphere.
110
How does photosynthesis remove carbon dioxide from the atmosphere?
• Green plants, algae, and phytoplankton absorb CO₂ and water.
• They convert it into glucose and oxygen.
111
What happens to glucose produced during photosynthesis?
• It is used to make complex carbohydrates (starch, fats, and proteins).
• These carbohydrates are stored in plants and passed on through food chains.
112
How is carbon transferred through food chains?
• When animals consume plants, they take in the carbon stored in the plant material.
• The carbon becomes part of the animal’s tissues.
113
What is the role of respiration in the carbon cycle?
• Organisms break down glucose for energy.
• During respiration, they release carbon dioxide into the atmosphere.
114
How do decomposers contribute to the carbon cycle?
• Decomposers break down dead plants and animals.
• This releases carbon dioxide back into the atmosphere.
115
What is the role of fossil fuels in the carbon cycle?
• Fossil fuels (coal, oil, and gas) store carbon from dead plants and animals.
• When burned, they release carbon dioxide into the atmosphere.
116
How is carbon released back into the atmosphere?
1. Respiration: Living organisms respire, releasing CO₂.
2. Decomposition: Microbes and fungi break down dead matter, releasing CO₂.
3. Combustion of fossil fuels: Releases stored carbon.
117
Why does atmospheric carbon dioxide vary throughout the day?
• Day: Photosynthesis occurs, removing CO₂.
• Night: Only respiration occurs, adding CO₂ to the atmosphere.
118
Why have atmospheric carbon dioxide levels increased since the 1960s?
• Human activities, especially burning fossil fuels, have increased CO₂ emissions.
• This contributes to global warming.
119
How does human activity disrupt the natural carbon cycle?
• Burning fossil fuels: Releases large amounts of CO₂.
• Deforestation: Reduces the number of trees available to absorb CO₂.
120
What is the link between fossil fuels and carbon storage?
• Fossil fuels are long-term stores of carbon, formed from dead plants and animals over millions of years.
• When burned, the stored carbon is released as CO₂.
121
What are the consequences of rising CO₂ levels?
• Global warming: Traps heat, causing the Earth’s temperature to rise.
• Climate change: Alters weather patterns and affects ecosystems.
122
How do plants store carbon?
• Plants absorb CO₂ during photosynthesis.
• They convert it into carbohydrates, which are stored in their tissues.
123
How is carbon transferred between plants and animals?
• Animals consume plants, absorbing the carbon stored in plant tissues.
• When animals respire or die, the carbon is released
124
What human activities reduce the removal of CO₂ from the atmosphere?
• Deforestation: Fewer trees reduce the amount of CO₂ removed.
• Land-use changes: Reduce the ability of ecosystems to absorb CO₂.
125
What is the significance of phytoplankton in the carbon cycle?
• They absorb large amounts of CO₂ from the atmosphere through photosynthesis.
• They play a major role in regulating atmospheric carbon levels.
126
How does burning biomass contribute to atmospheric CO₂?
• Biomass burning releases stored carbon back into the atmosphere.
• This contributes to increasing CO₂ levels
127
What role do the oceans play in the carbon cycle?
• Oceans absorb CO₂ from the atmosphere.
• Marine plants (phytoplankton) use CO₂ for photosynthesis.
128
Why is atmospheric carbon dioxide concentration increasing?
• Combustion of fossil fuels releases CO₂.
• Deforestation reduces carbon absorption.
• Industrial activities increase CO₂ emissions.
129
What are detritivores and what is an example?
Detritivores are organisms that help breakdown organic waste into small pieces, speeding up decomposition
130
what is the difference between a decomposer and a detritivore?
Decomposers are microorganisms that breakdown dead material at a microscopic level. Detritivores are small animals that shred dead material into smaller pieces increasing surface area for decomposers
131
Give examples of detritivores and what they break down.
1. Earthworm- leaves
2. Woodlouse- wood
3. Maggot- animal tissue
132
How do decomposers release nutrients?
Bacteria and fungi release enzymes to breakdown substances in organic matter. They absorb some soluble nutrients and release the rest into the environment.
133
What factors affect the rate of decomposition?
1. Warm Temperatures
2. Moist Environments
3. Aerobic Conditions
134
How does warm temperatures affect the rate of decomposition?
Increase enzymes activity, but too much heat de-natures the enzymes slowing down decomposition
135
How does moist environments affect the rate of decomposition?
Water is needed for reactions ; a lack of water slows or stops decomposition.
136
How does aerobic conditions affect the rate of decomposition?
Oxygen is required for microorganisms; anaerobic conditions slow down decomposition
137
State 3 ways you could slow the rate of decomposition
1. Keep materials in a cold environment
2. Store materials in a dry place
3. Keep materials in an air tight container to reduce oxygen
138
What is the formula for calculating the rate of decay of biological matter?
Rate of decay (g/day) = change in mass (g) / change in time (days)
139
Why do some gardeners add worms to their compost bins?
Detritivores break down organic material into smaller pieces, increasing surface area for decomposers and speeding up decomposition
140
Why does keeping food in an air tight container slow down decomposition?
It reduces oxygen which slows down the activity of aerobic decomposers
141
Describe how microorganisms cause materials to decompose
Micro organisms release enzyme that breakdown substances in organic material. They absorb some nutrients and release the rest into the environment.
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