Chapter 5: Higher Level Ecology

Question 1

what is a distorted pyramid of numbers?

Answer 1

when the pyramid does not have the largest number of organisms at the bottom

Question 2

what is an inverted pyramid of numbers?

Answer 2

when the pyramid starts the with smallest number at the bottom and gets bigger

Question 3

what are the 4 factors that control population?

Answer 3

competition
predation
parasitism
symbiosis

Question 4

what is competition?

Answer 4

when organisms of the same or different species fight for the same resources that are in short supply e.g. shelter, food

Question 5

what are the kind of competition is there?

Answer 5

intra-specific competition

inter-specific competition

Question 6

what is inter-specific competition?

Answer 6

it is between members of different species

Question 7

what is intra-specific competition?

Answer 7

it is between members of the same species

Question 8

what are the two types of competition and explain them?

Answer 8

contest competition - involves an active physical confrontation between two organisms - one winner
scramble competition - each organism tries to acquire as much of the resource as possible - they both win but will soon run out of resource

Question 9

what is predation?

Answer 9

the act of some animals capturing and killing other animals for food

Question 10

what is a predator?

Answer 10

an animal that hunts, captures, kills other animals for food

Question 11

what are 4 adaptations of predators?

Answer 11

keen senses and sharp teeth
change diet to suit prey availability
live and hunt in packs
camouflage

Question 12

what is prey?

Answer 12

an organism that are hunted and eaten

Question 13

what are 4 adaptations of prey?

Answer 13

plants may have thorns, stings or spines
nasty taste when eaten e.g. giant hogweed
faster than predator
camouflage

Question 14

what does a graph representing predator/prey relationship look like?

Answer 14

predation initially increases the number of predators and decreases the number or prey
but when one decreases so does the other and when one increases so does the other
this cycle repeats itself

Question 15

why does the population of prey and predator never go to zero?

Answer 15

the species may become extinct

Question 16

what are parasites?

Answer 16

an organism that benefits from another and does harm to it

Question 17

what is symbiosis?

Answer 17

where two organisms of different species have a close, specific relationship with each other where at least one benefits and no harm is done to the other

Question 18

what is mutualism?

Answer 18

symbiosis

Question 19

give an example of a symbiotic relationship between organisms.

Answer 19

bacteria living in the colon - bacteria produce vitamin B2 and vitamin K
the body gives suitable environment for the bacteria to live

Question 20

what is population density?

Answer 20

the measurement of the numbers of a species of a stated area

Question 21

why does a population increase?

Answer 21

increase in birth rate, decrease in death rate, immigration

Question 22

why does a population decrease?

Answer 22

high mortality rate and emigration

Question 23

explain the 4 steps in the normal population curve.

Answer 23

1. organisms arrive and adapt to their new environment
2. growth takes place rapidly due to newly available food
3. growth constraints are felt - predation, overcrowding, available food
4. growth settles at a level that the environment can support

Question 24

what percentage of the world live in asia?

Answer 24

66%

Question 25

what is the main cause of increased population?

Answer 25

decreased death rates

Question 26

what years was the great irish famine?

Answer 26

1845-47

Question 27

what are the four factors affecting population?

Answer 27

war, famine, disease, contraception

Question 28

what are the four controls of disease?

Answer 28

vaccines - reduce the incidence of the following diseases: diphtheria, whooping cough, tetanus, polio, meningitis, tb
sanitation and insecticides - control malaria, yellow fever, sleeping sickness
anaethetics - improved surgical methods
antibiotics - prevent deaths that would have been causes by bacteria

Question 29

what affect does war have on population?

Answer 29

reduces the population, the effects can be temporary, increased birth rates immediately after

Question 30

what affect does contraception have on human population?

Answer 30

increased availability of contraception has led to a decrease in birth rates, developed countries have an average of 2.1 children per family, the fertility rate in developing countries has decreased from 6.1 in 1970 to 3.5 today