Higher Level Ecology

Question 1

What does the pyramid of numbers represent?

Answer 1

The number of organisms at each trophic level in a food chain

Question 2

What does the Pyramid shape tell you?

Answer 2

Number of organisms decline as you go up due to large energy losses between each trophic level
Body size of the organism usually increases as you go up a pyramid of numbers

Question 3

What are the limitations of the pyramids of numbers?

Answer 3

They did not take into account the size of the organisms

A huge oak tree may be represented by a narrow rectangle

Question 4

What are the two main shapes of pyramids?

Answer 4

Normal pyramid and inverted pyramid

Question 5

What factors control populations?

Answer 5

Completition
Predation
Parasitism
Symbiosis

Question 6

What is competition?

Answer 6

active struggle between organisms for a resource that is in short supply

Question 7

What would plants compete for?

Answer 7

Space, light, water and minerals

Question 8

What would animals compete for?

Answer 8

Food, water, shelter, territory, mates

Question 9

What is intra-specific competition and give an example

Answer 9

It takes place between members of the same species

Rabbits compete with eachother for food

Question 10

What is inter specific competition and give an example

Answer 10

Occurs between members of different species

Blackbirds and thrushes for insects

Question 11

How do animals avoid competition?

Answer 11

Adapt to their environments, which may involve changes in feeding habitats, camouflage and reproductive strategies

Question 12

What are the two main types of competition?

Answer 12

Contest competition and scramble competition

Question 13

What is contest competition?

Answer 13

Involves an active physical confrontation between two individual organisms

Question 14

What is scramble competition and give an example

Answer 14

All of the competing individuals get some of the resource

Overcrowding of seedlings in flower beds

Question 15

What does scramble competition cause?

Answer 15

Large changes in population sizes and in general reduces the numbers in a population

Question 16

An adaptive technique to survive competition

Answer 16

Blackbird ‘song’ to warn competitors to stay away

Yellow petals of buttercups to attract insect pollinators

Question 17

What is predation?

Answer 17

It’s the catching, killing and eating of another organism

Question 18

What is a predator?

Answer 18

It’s an organism that catches, kills and eats another organism

Question 19

What is prey?

Answer 19

It’s the organism that is eaten by the predator

Question 20

Adoptions of predators

Answer 20

Hawks - excellent eye sight
Ladybirds - strong mouth parts to enable them to chew aphids
Fox - reddish fur for camouflage to avoid detection by rabbits
Long canine teeth to kill prey
Great speed to outrun prey to capture

Question 21

Adaptions of prey

Answer 21

Rabbit -
Digs narrow underground burrows
Long ears - detect predator
White tail - conspicuous warning signal to other rabbits

Question 22

What is parasitism?

Answer 22

It occurs when two organisms of different species live in close association and one organism obtains it’s food from, and to the disadvantage of the other organism

Question 23

What are the two types of parasites?

Answer 23

Exoparasites and endoparasites

Question 24

What are Ectoparasites and example

Answer 24

Lives on outside of host, Feed on outside of host eg, mosquito

Question 25

What are endoparasites and example

Answer 25

Feed in a living host, bacteria of disease

Question 26

How do parasites differ from predators?

Answer 26

Smaller than the host, often attack from within, they're dependent on the one particular host, don't kill only do small amount of damage

Question 27

What is symbiosis?

Answer 27

Occurs when two organisms of different species live in close association and at least one of them benefits

Question 28

What is mutualism?

Answer 28

Form of symbiosis where both organisms benefit from association

Question 29

Example of symbiosis mutualism

Answer 29

Nitrogen fixing bacteria and legumes - bacteria provide nitrates for plant to make protein and plant provides carbohydrates and anaerobic conditions

Question 30

How does symbiosis influence human population?

Answer 30

Increases number of both organisms

Question 31

What are the factors that contribute to predator-prey interactions

Answer 31

Availability of food -increase in prey, increase in predators, prey killed off less food so they decline Movement of predators

Question 32

Factors affecting human growth

Answer 32

War, famine, contraception, disease

Question 33

How do different types of mouth parts reduce competition?

Answer 33

They eat different food - or different parts of food

Question 34

Adoration of plants as prey

Answer 34

Thorns such as cacti

Question 35

Effects of predation in ecosystem

Answer 35

Maintains prey species at sustainable level | Major factor in evolution of prey species

Question 36

List two species from an ecosystem you have studied which are involved in a predator-prey relationship

Answer 36

Ladybirds and aphids

Question 37

Draw a graph to show how population numbers fluctuate in a predator-prey relationship and explain fluctuations

Answer 37

[page 33 in exam papers] The number of prey builds up and therefore the number of predators will rise As a result, there’s more prey being killed and so the number will fall In turn, this will result in fewer predators and so numbers will fall as they die or move away Eventually, the number of prey will rise again and cycle will begin again

Question 38

Graph of phytoplankton

Answer 38

Page 82

Question 39

Suggest two reasons why the human population increased so rapidly from the mid 1880’s

Answer 39

Better living conditions Better nutrition Improved medicine

Question 40

Suggest what could happen to biological diversity as the human population continues to increase

Answer 40

Inc - more people different

Question 41

Mention three main ways in which waste can be minimised

Answer 41

Reduce Reuse Recycle

Question 42

What is the role of microorganisms in pollution control

Answer 42

Decomposers

Question 43

Name three factors that controls wild populations

Answer 43

``` Competition Predation Disease Parasitism Hunting ```

Question 44

What deduction can be made in a particular area where the population of a predator did not decline following a big reduction in the population of its main prey

Answer 44

Different prey

Question 45

What deduction can be made when mortality levels resulting from infection tend to decline over the years

Answer 45

Immunity develops

Question 46

What deduction can be made where some members of the species remain in a general area throughout life and some members are migratory and the mortality levels tend to be higher in the migratory part of the population

Answer 46

Hazards encountered on migration

Question 47

What deduction can be made when there is a greater variety of herbaceous plants in areas where grazing species such as rabbits are more plentiful than in areas where grazing species are less plentiful

Answer 47

Reduced competition

Question 48

Where are primary producers found in a pyramid of numbers

Answer 48

Bottom

Question 49

Construct a simple inverted pyramid of numbers using named examples

Answer 49

Robin [small] Ladybird [kinda big, smaller than aphids] Aphids [big] Oak tree [small] Spider mites [small but not as small as oak tree and smaller than greenfly] Mites [largest] Greenfly [larger than oak tree] Oak tree [smallest]

Question 50

Suggest an alternative to the use of pesticide for controlling the population of a species

Answer 50

Biological control | Genetically modified plant

Question 51

When the pesticide killed both the predator and the prey, the prey quickly reinvaded the strawberry fields while their predator returned much slowly, why did this happen?

Answer 51

Predator eliminated Developed resistance to pesticide Food available

Question 52

Comment on relative sizes due to pyramid of numbers

Answer 52

``` Broader = smaller it is Narrower = larger it is ```

Question 53

If the population of prey decreases suggest a possible consequence for the predators

Answer 53

Death, Migration

Question 54

Competition is generally more intense between members of the same species than between members of different species?

Answer 54

True | Same niche, same requirements for food, shelter, breeding etc

Question 55

Suggest two reasons why birds migrate

Answer 55

Climate Breed Food

Question 56

Suggest three possible effects of the disappearance of a plant on the populations of other plants and animals in the ecosystem

Answer 56

Animals dependant on plant as good may die or migrate