Ecology 1st year Topic 9 Flashcards

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1
Q

Define ecology

A

The study of how organisms are affected by their environment and by other organisms

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2
Q

Define population

A

It is a group of individuals living together in a particular geographical area at the same place at the same time and can interbreed.

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3
Q

Define habitat

A

It is a specific locality within an ecosystem which contains a particular set of environmental conditions and its own particular adapted community of organisms.

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4
Q

Define species

A

A group of living organisms that are able to interbreed with each other to produce fertile offspring. These fertile offspring will not produce “viable” offspring with members of a different species.

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5
Q

Define a community

A

A group of naturally occurring populations of different species that lives together and interact as a self-contained unit in the same habitat.

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6
Q

Define an ecosystem

A

The ecological system based on the relationship between all the living organisms and the non-living component of the environment within which they occur naturally.

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7
Q

Define the biosphere

A

All ecosystems on earth make up the biosphere.

The biosphere consists of all the total volume, of air, land and water that supports life around the earth’s surface.

Life in the biosphere depends on the sunlight’s energy, on the circulation of heat and on essential nutrients.

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8
Q

What is an ecological niche?

A

It refers to the functional role of an organism within an ecosystem

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9
Q

Define a biome

A

A biome is a large ecosystem defined by its distinctive vegetation, animals, and climate, influenced by abiotic factors like light, wind, soil, rainfall, temperature, and nutrients. Examples :grasslands

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10
Q

Define food chain

A

A food chain shows how energy is passed on from 1 organism to another by showing what each organism eats.

(When 1 organism feeds on another)

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11
Q

Give 3 examples of food chains

A

Grass: grass hopper: frog:snake

Sun:grass:slug:sparrow

sun:mosses:slug:devil’s coach horse

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12
Q

Distinguish between prey and predator

A

Prey: the organism which gets eaten

Predator: the organism eating the prey (eater)

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13
Q

Distinguish between producers
primary consumer
secondary consumers and tertiary consumers

A

producers: they are usuually autrotrophic organisms

Primary consumer
secondary consumer
tertiary consumer

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14
Q

Define trophic level

A

It is any of the feeding levels from which energy passes through, as it proceeds through the ecosystem

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15
Q

Define a food web

A

It consists of many interacting food chains. It shows the flow of energy and the decomposers involved

Organisms can feed on more than one organism

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16
Q

What is the role of plants in food chains or food webs?

A

Plants they absorb sunlight energy in order to convert carbon dioxide and water into glucose and oxygen through the process of photosynthesis which occurs in the chloroplast

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17
Q

Why are food webs important?

A

Food webs are important because if one of the consumer’s food source dies, then the consumer will have another food source available ensuring survival for that consumer

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18
Q

Define competition

A

The struggle for the utilization of resources such as food,light,space,mating,companions,oxygen or carbon dioxide etc.,by one or more organisims of the same species (intra-sepcific competition,or by diffrent species (inter-specific competition),that are living together in a community

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19
Q

Define intra-specific competition

A

The struggle for the utilization of resources such as food,light,space,mating,oxygen or carbon dioxide etc by one or more organisims of the same species that are living together in a community

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20
Q

Define inter-specific competition

A

The struggle for the utilization of resources such as food,light,water,mating,space,oxygen or carbon dioxide etc by different members of a different species that are living together in a community

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21
Q

Mention some factors which are competition for living organisms

A

Space
food
mate

22
Q

What do we mean by competition for space?

A

Animals compete for territory. If they are not successful they will find it much more difficult to attract a mate and cannot breed

Seedlings compete for space in order to germnate grow and photosynthesize,in order to + for light and water.

23
Q

What do we mean by competition for food?

A

Members of the same species and of a different species compete for food

ex: different species of birds compete for the same food

24
Q

What do we mean by competition of mate?

A

In many species the male competes for the female, therefore the best genes will be passed on.

Ex; birds will attract the females by showing off their colours or doing a courtship dance

Or some primates will try to attract females by holding an infant to give off the impression that they are good fathers

25
Q

Define parasitism

A

It occurs when one species lives in or on another organism. This is the host. The parasite often harms and weakens the host,whilst the parasite obtains food at the host’s expense.

26
Q

What are the 2 types of parasites?

A

Ectoparasites and endoparasites

Ectoparasites: attach themselves outside of the body’s host and many only form temporary associations. ex: ticks or fleas

Endoparasites: live inside the host’sbody and it becomes its habitat,giving it food,shelter and protection

ex: bacteria or viruses

27
Q

Define autotroph

A

Organisms which can synthesie their own food from inorganic molecules,like plants or bacteria. Halophytic /chemophytic

28
Q

Define heterotroph

A

Organisms which are dependant on obtaining organic food molecules from its environment or other autotrophs because its unable to synthesize its own food

29
Q

Define decomposers

A

Decomposers are living organisms like bacteria or fungi which obtain their nutrients by breaking down dead decaying organic matter. Therefore they are important in the break down of dead organisms,

30
Q

Define detritivores

A

Living organisms like bacteria which obtain their nutrients from small organic debris fragments which have been generally left by decomposers. Therefore detritivores help decomposers.

31
Q

Define predation

A

Predators are organisms which feed on prey

If the prey will decrease then predators will starve

If the predators decrease, then the prey increases

If prey increases, there will be more food for the predators

Even human impact influences the concentrations of prey and predators

32
Q

True or false

Predators increase if the conditions are favourable

A

True because they can breed in the optimum conditions

33
Q

What makes a good predator?

A

Some predators hunt in packs and then share the food. Some predators also target the young and this eliminates the weak organisms from the environment

Or migrating to areas where they prey is more plentiful

34
Q

How do prey try to escape their predators?

A

Camoflauge:by blendng in with their surroundings

Some prey mimic other animals

Some prey have warning colours

Some try to run,swim or fly faster than the predators,whilst other stay in groups

35
Q

Define symbiosis

A

Any type of ongoing persistent biological interaction between 2 organisms

For example: cellulose digesting bacteria in herbivores OR

nitrogen fixing bacteria with plants

36
Q

Define mutualism

A

When 2 organisms live in relation to each other and both gain from the relationship

37
Q

Define commensalism

A

An association between 2 organisms where one organism benefits whilst the other is not affected

38
Q

True or false

Energy does not get recycled, but inorganic nutrients like nitrogen and carbon dioxide do get recycled

A

true

39
Q

Why is only 10% of energy passed through one trophic level to another in food chains?

A

All energy initiially comes from sunlight,however energy in ecosystems in the end it gets lost as heat.Energy is never recycled because energy can not be created nor destroyed.

Energy gets released in diffrent forms

The other inorganic nutrients that autotrophs obtain from the soil or water THEY ARE passed through from one organism to another.

When animals die the decomposers will obtain their nutrients from the dead animals. However at this stage the the energy is lost as heat and the inorganic nutrientsare taken up by the soil or the water to be taken up again

40
Q

Continue to elaborate

A

Energy enters the ecosystem as light.

HOWEVER only 1% of this energy is used by the plant because some of the energy will be used for photosythesis,some energy will be lost by transpiration, some energy will be reflected back by the leaf (lost),and the rest is lost as heat. (Gross primary production)

Therefore 90% of the energy is lost. Furthermore,10% of the energy will be passed on from the plants to the primary consumer

Therefore at each trophic level energy is lost mostly due to heat but other factpors include egestion,excrtion,growth or movement or inedible food

Then all the organisms die and will be used as food fro the decomposers. Then the last of the eenrgy is extracted and lost as heat.

41
Q

When does the greatest loss of energy happen and where does the greatest gain of energy happen/more efficient?

A

More efficient: from the primary consumer to the secodary consumer because a large ammount of flesh is digested and absorbed

Loss: from the producer to the consumer

Much of the energy is obtained from plants, because when it comes to the animals the energy is lost from each tropic level.

42
Q

What is a pyramid of energy?

A

A pyramid of energy represents the flow of energy through each trophic level in an ecosystem through a fixed period of time

43
Q

Explain the structure of a pyramid of energy

A

In order for the ecosystem to sustain itself and remain healthy, the lower trophic level must contain a higher amount of energy than there is at higher trophic levels. This allows for organisms on the lower trophic levels to not only maintain a stable population but to also transfer energy up the pyramid.

44
Q

Why are the natural cycles important?

A

Because in natural cycles resources are being used and replenished continuously

45
Q

What are the 4 steps of the nitrogen cycle?

A

Nitrogen fixation
Decay
nitrification
denitrification

46
Q

Explain the nitrogen cycle and draw a diagram

A

Nitrogen is very important for all living organisms. Regarding plants, they cannot make use of atmospheric nitrogen and needs to be changed into a usable form taken up by plants. In order to produce nitrates,urea and ammonia.

Nitrogen fixation can occur by 3 processes

Lightning: the enormous amount of energy which is found in lightning can break up nitrogen into nitrogen molecules. This will cause the nitrogen molecules to react with oxygen in the atmosphere to form oxides of nitrogen. These oxides of nitrogen will dissolve into the rainwater and will form nitrates . These nitrates will be carried into the soil and will be taken up by plants.

Nitrogen can also be fixed industrially: through a temperature of 600 degrees and with the use of a catalyst and with the use of hydrogen can be combined to form ammonia.. but most of it is further processed to form urea and ammonium nitrate

Nitrogen can also be fixed through nitrogen fixing bacteria. These types of bacteria can be found living directly in the soil or in the root nodules of leguminous plants. The nitrogen fixing bacteria will change nitrogen into ammonia, urea and uric acid.

After decay is going to occur. This is because the plants will take up the organic nitrogen compounds and these will be passed on to each trophic level . Now the nitrogen is going to leave and re-enter the ecosystem through the excretions of organisms. The decomposers are going to break down these excretions and will form ammonia which is going to re-enter back into the soil.

After the process of decay, the ammonia is going to get converted into nitrates/nitrites by the process of nitrification by nitrifying bacteria

After the process of nitrification, the nitrates will be converted back into atmospheric nitrogen by the process of denitrification by denitrifying bacteria completing the nitrogen cycle

47
Q

What is leaching?

A

When excess nitrates get into the soil,they can actually get lost due to excess water because they got disposed underneath the soil layers and this is not going to let the plants absorb the nutrients and will not allow the decomposers do their job. This can also occur due to excess fertilizers.

+ EUTROPHICATION

48
Q

What is the carbon cycle and draw a diagram

A

The first part of the carbon cycle is photosynthesis.

Plants will absorb atmospheric carbon dioxide from the atmosphere in order to carry out photosynthesis and convert carbon dioxide and water into sygar and oxygen. The carbon in the carbon dioxide is used to make su stances like cellulose, starch ,proteins and other pigments

The carbon dioxide is going to get released into the atmosphere agin by cellular respiration. Because plants will oxidize sugar in order to obtain energy and carbon dioxide is released as a waste product

Now eventually all plants and animals die. Decomposers will break down the remains of the dead animals and plants as a source of energy and will turn the carbon compounds into carbon dioxide

Regarding combustion : when carbon containing fossil fuels burn this actually increases the amount of carbon dioxide into the atmosphere. Fossil fuels are formed formed from ancient organisms that lived millions of years ago.

Therefore respiration and burning of fossil fuels increases the amount of carbon dioxide levels in the atmosphere

49
Q

Mention 2 ways how the carbon dioxide levels increase in the atmosphere in an anthropogenic way

A

Burning of fossil fuels
Deforestation

50
Q

Mention some other greenhouse gases

A

Methane
CFCs

These gases have a major depletion and negative effect on the ozone layer which is used to keep out harmful UV rays from the sun. If the ozone layer depletes, it can actually contribute to issues like skin cancer

51
Q

What are fossils?

A

Fossils are formed from the remains of dead plants and animals. Ad they are buried pressure and heat from the earth turn them into rock. The carbon from these organisms actually gets trapped and forms fossil fuels like natural gas, oil and coal. When these fossil fuels are burnt it contributes to increased levels of carbon dioxide into the atmosphere which affects the carbon cycle and causes climate change.