Ch 19 - (Organisms and the environment)

Question 1

What is the main principal source of energy?

Answer 1

The sun

Question 2

how does energy flow through organisms?

Answer 2

• Light energy from sun and chemical energy in organisms
• energy is transferred to the environment as heat

Question 3

what does a food chain?

Answer 3

Transfer of energy from om organism to organism

Question 4

What do arrows in the food chain show?

Answer 4

Transfer of energy from one trophic level to another

Question 5

How is energy transferred from one organism to another?

Answer 5

Ingestion

Question 6

define producers

Answer 6

• organisms that produce their own organic nutrients usually using energy from sunlight

Question 7

Define herbivore

Answer 7

animal that gets its energy from eating plants

Question 8

Define carnivore

Answer 8

an animal that gets its energy by eating other animals

Question 9

Define primary consumers

Answer 9

herbivore - they feed on producers (plants)

Question 10

Define secondary consumers

Answer 10

predators that feed on primary consumers

Question 11

Define tertiary consumers

Answer 11

predators that feed on secondary consumers

Question 12

Define decomposers

Answer 12

Bacteria and fungi that get their energy from feeding off dead and decaying organisms and undigested waste

Question 13

What is a food web?

Answer 13

Network of interconnected food chain

Question 14

What does a food Web show?

Answer 14

• Show connections between organisms
• animals rarely exist on just one type of food source
• show interdependence on how a specie affects another

Question 15

Why do most change in populations happen?

Answer 15

• human impact
• overharvesting of food species
• introduction of foreign species to a habitat

Question 16

What do change in population do die to interdependence?

Answer 16

Long lasting knock on effects

Question 17

What does a pyramid of numbers show?

Answer 17

How many organism there are are

Question 18

What does the width of a box show in a pyramid?

Answer 18

Number of organisms

Question 19

Why may some pyramids not be pyramid shaped?

Answer 19

Size of organism is also important

Question 20

What are the rule to remember when drawing a pyramid of numbers

Answer 20

1. You cannot change trophic levels of organisms
2. Larger an individual organism is, the less of them there are

Question 21

What does pyramid of biomass show?

Answer 21

how much mass the creatures at each level would have without including all the water that is in the organisms

Question 22

How are biomass pyramids like, and why?

Answer 22

• ALWAYS pyramid shaped
• cuz mass of an organism has to decrease as you go up a food chain
• provide better idea of quantity

Question 23

How is energy passed on?

Answer 23

Has to be consumed (eaten)

Question 24

What happens to energy in energy of pyramids?

Answer 24

• not all of the energy grass plants receive goes into making
• only the energy that is made into new cells remains with the organism to be passed on

Question 25

Is the energy that is made into new cells consumed?

Answer 25

- No - energy is stored in these parts and so it does not get passed on

Question 26

What is majority of energy in an organism used?

Answer 26

- making waste products - as movement - as heat - as undigested waste

Question 27

How is the human energy transfer in food chain?

Answer 27

- omnivore - choice of what we eat - impact on what we grow

Question 28

What nutrients does the carbon cycle involve?

Answer 28

Carbon and nitrogen - recycled

Question 29

What happens to carbon in the cycle?

Answer 29

- Carbon is taken out of the atmosphere in form of CO2 for plants to be sued in photosynthesis - passed onto organisms by feeding - returned as CO2 thru respiration - decomposed dead organisms form fossil fuels - burnt fossil fuels releases CO2

Question 30

What are the main issues causing an increase in CO2?

Answer 30

- increased use of fossil fuels - mass deforestation by reducing the amount of procedures

Question 31

What is nitrogen?

Answer 31

An element required to make proteins

Question 32

Why can't plants or animals absorb N2?

Answer 32

- very stable - cannot be broken down

Question 33

what are 2 ways that nitrogen can be converted into a usable form?

Answer 33

1. Nitrogen fixing bacteria - lives in the soil 2. Lightening - splits the bonds between N and turns into nitrous oxide

Question 34

Explain how nitrogen is transferred?

Answer 34

- plants absorb nitrogen in form of nitrates from soil - animals eat plants, so it is passed up by food chain - waste send nitrogen out of the body - waste and dead species decay and nitrogen group is broken into ammonia - plants can't absorb ammonium compounds so nitrifying bacteria concerts it to nitrites then nitrates

Question 35

What does denitrifying bacteria do?

Answer 35

- takes nitrates out of soil - reduces soil fertility

Question 36

Define population.

Answer 36

A group of organisms of one species living in the same area at the same time

Question 37

Define a community

Answer 37

All of the populations of different species in an ecosystem

Question 38

Define an ecosystem.

Answer 38

a unit containing the community of organisms and the environment interacting together

Question 39

What do all living organisms compete with each other for?

Answer 39

Flood, water and living space.

Question 40

What are the 3factors required for population growth?

Answer 40

1. Food supply 2. Predation 3. Disease

Question 41

What are the 4 stages of a population growth curve?

Answer 41

1. Lag phase 2. Log phase (exponential phase) 3. Stationary phase 4. Death phase

Question 42

What happens in lag phase?

Answer 42

- organism adapting to the environment -

Question 43

What happens in log phase or exponential phase?

Answer 43

- food supply is abundant - birth rate is rapid - death date is low - growth is exponential

Question 44

What happens in stationary phase?

Answer 44

- populations level out - due to nutrient factor in environment - birthrate becomes limited

Question 45

What happens in death phase?

Answer 45

- population decrease - food supply is short - metabolic waste produced by population builds up to toxic levels

Question 46

What are organisms in a natural environment unlikely to show rapid growth unlike sigmoid growth curve?

Answer 46

Other factors

Question 47

What's re the factors that's effect population growth

Answer 47

- changing temperature or light - predators - disease - immigration (individuals moving into area) -emigration (individuals moving out of area)