Unit 2.1 & 2.2

Question 1

Ecosystem

Answer 1

A community of interdependent organisms and the physical environment they interact
Made up of biotic and abiotic factors

Question 2

Biotic components of ecosystem

Answer 2

anything that is living and any interactions between the living components
organisms and plants
- producers, consumers, decomposers
- predation, disease, compettion

Question 3

Species

Answer 3

is a group of organisms with common characteristics that can interbreed to produce fertile offspring.

Question 4

Population

Answer 4

is a group of individuals of the same species living in the same area at the same time.

Question 5

Abiotic components

Answer 5

non living physical factors - temperature, sunlight PH, salinity, precipitation

Interact with biotic elements

Question 6

habitat

Answer 6

the environment in which a species usually lives.

Question 7

Niche and example

Answer 7

the role an organism plays and the position it holds in the environment. It includes all the interactions the organism has with the abiotic and biotic environment.

ex. Red eyed frog - carnivorous - prevents over populartion and are also source of food to other

Question 8

Liming factor

Answer 8

resources in the environment that limit the growth, abundance and distribution of organisms/populations in an ecosystem. may be abiotic or biotic and they determine the carrying capacity

Question 9

Carrying capacity

Answer 9

maximum number of individuals of a species that the environment can sustainably support in a given area.

Question 10

Population growth curves

Answer 10

Question 11

Predation

Answer 11

is where one organism (the predator) hunts and kills another (the prey) in order to provide it with the energy for survival and reproduction.

Question 12

Predator prey relaionship

Answer 12

1. Prey higher number than predators –> loss of enegry through food chain
2. Populations peak out of sync

Question 13

Parasitsm

Answer 13

is when an organism (the parasite) takes nutrients from another organism (the host).

Question 14

Mutualism

Answer 14

Where two organisms of different species exist in a mutually beneficial relationship.

ex. Bacteria in the intestines of cows to facilitate digestion celliulose. Cows better digestion, bateria safe place to live

Question 15

Competirion

Answer 15

When organisms compete for scarce resoyrces.
If there is not enough one species will experience lower growth rates and suvivral of both might be impossible which affects population dynamics

Question 16

Photosyntheis and formula and purpose

Answer 16

the process that Primary producers undergo in most ecosystems to convert light energy into chemical energy

carbon dioxide + water = glucose + oxygen

Photosynthesis produces raw material for biomass production

Question 17

Respiration, formula and implication

Answer 17

is the conversion of organic matter into carbon dioxide and water in all living organisms, releasing energy.

glucose+oxygen = carbon dioxide + water

Large amounts of enegry are released, increasing energy in the eco-system while mantaining it low on organsms

Question 18

Trophic level

Answer 18

the position an organism (or group of organisms in a community) occupies in the food chain.

Question 19

Food chain vs food web

Answer 19

Food chain
- simple single lines showing what eats what
- only one arrow
- only 1 TL for each organism

Food web
- internonnected food chains - complex
- many at different trophic levels

Question 20

Food chain demomstrate 1st and 2nd law of thermo because

Answer 20

Energy is neither created nor destroyed (1st law) in the food chain and as energy passes along the food chain entropy increased (2nd law).

Question 21

How much energy. passes from one trophc level to the next

Answer 21

10%

Question 22

Ecological Pyramid

Answer 22

Trophic level in order - primary producers - quaternary consumers
flow of energy up the pyramid
length of bar proportional to what its showuing

Question 23

Pyramids of numbers adv and disav

Answer 23

Shows number of organisms at each trophic level
Adv:
- non destructive method of data collection
- good for comparing changes over time
Disadv:
- does not take into consideration size of organism
- numebers may not be accurate

Question 24

Pyramid of Biomass adv disv

Answer 24

A graphical representation of the amount of biomass at each trophic

adv; overcome problems of number pyramid
disadv
- measuriing parts that do not contribute
- must be extrapolated
- destructive methods
- seasonal changes may vary

Question 25

Biomass

Answer 25

Biomass is the total amount of living matter in a given area so it represents the standing stock of energy storage at each trophic level

measured as dry weight

g m–2

Question 26

Pyramid of productivity

Answer 26

refer to the flow of energy through a trophic level,
indicating the rate at which that stock/storage is being generated

J m-2 yr-1.

adv:
- most accurate
- rate of production over time
- compasirons allowed

disv:
- not esasy to collect data
- difficulut to assign trophic level

Question 27

Bioaccumulation

Answer 27

The increase in the concentration of a pollutant in an organism as it absorbs or it ingests it from its environment.

Question 28

Biomagnification

Answer 28

the increase in the concentration of the pollutant as it moves up through the food chain.

Question 29

Bio magnification and accumulation DDT case studty solo leelo

Answer 29

Fast facts about DDT:

It is a persistent organic pollutant (POP).
It is stored in the fat cells of animals.
Fat-soluble toxins are a problem because they cannot be eliminated through sweating or urination so they stay in the body for a long time.
It has a half-life of 15 years, which means if 1 Kg of DDT is released into the environment 500 grams of it will still be there after 15 years.
It results in bioaccumulation and biomagnification.
DDT is sprayed on land to control malarial mosquitos, and whatever is sprayed on land ends up in nearby water bodies. The primary producers of the aquatic food chain are plankton and they essentially live in a dilute DDT soup. All the time they live in that soup they are absorbing and accumulating DDT (or mercury or any other such toxin). Just as phytoplankton absorb and accumulate DDT from the surrounding environment the herbivores ingest and accumulate DDT from their food source – the phytoplankton. This applies to any organisms in the polluted environment.

Bioaccumulation is not the worst of it. Due to the nature of the food chain and the loss of energy and biomass at every trophic level biomagnification becomes an issue. Let us turn the 10% law around a little. If each phytoplankton only passes on 10% of its energy that means (more or less) that the zooplankton must eat ten phytoplankton to get enough energy to live – this is not exactly true but it is better if the maths is simplified. As the zooplankton eats ten phytoplankton it picks up ten units of DDT too. The same rule passes up through the food chain and the DDT magnifies 10 fold every time. Small fish eat zooplankton - 10 × 10 = 100 units of DDT. Large fish eat small fish 10 × 100 = 1,000 and so on. So by the time you get to the top of the food chain there is a lot of DDT in the organisms and it has reached harmful levels. The impact of DDT is discussed in section DDT.