Chapter 4-Ecology

Question 1

Species

Answer 1

A group of organisms with a common ancestor that can breed and produce fertile offspring

Question 2

Population

Answer 2

A group of organisms of the same species who live in the same area at the same time

Question 3

What are the 2 types of method to obtain nutrients, and the explanations?

Answer 3

1) Autotrophic = organisms that make their own C compounds

2) Heterotrophic = organisms that obtain C compounds from other organisms

Question 4

Detritrivores

Answer 4

Heterotrophs that obtain organic nutrients from detritus by internal digestion

Question 5

Saprotrophs

Answer 5

Heterotrophs that obtain organic nutrients from dead organic matter by external digestion
→ secretes enzymes into the environment to digest the dead organic matter

Question 6

Communities

Answer 6

All the populations of different specie living together and interacting with e.o
(All the populations in an ecosystem)

Question 7

Ecosystem

Answer 7

A community forms an ecosystem by its interactions with the abiotic environment

Question 8

3 requirements of a sustainable ecosystem

Answer 8

1) Nutrient availability
2) Detoxification of waste products
3) Energy availability

Question 9

Mesocosm

Answer 9

Self contained ecosystem

→ Allows a small part of the natural environment to be observed under controlled conditions

Question 10

3 groups of autotrophs that can carry out photosynthesis

Answer 10

1) plants
2) eukaryotic algae
3) cyanobacteria

Question 11

Food chain

Answer 11

A sequence of organisms, each of which feeds on the previous one

Question 12

3 activities that living organisms need energy for?

Answer 12

1) Synthesising large molecules like DNA, RNA and proteins
2) Pumping molecules or ions across membranes by active transport
3) Moving things around inside the cell, s.a chromosomes or vesicles, or in muscle cells the protein fibres that cause muscle contraction

Question 13

The energy conversions performed by living organisms (4)

Answer 13

Light energy → chemical energy in photosynthesis
Chemical energy → kinetic energy in muscle contraction
Chemical energy → electrical energy in muscle cells
Chemical energy → heat energy in heat generating adipose tissue

Question 14

Laws of thermodynamics

Answer 14

Heat passes from hotter place to a cooler place

→ heat produced in living organisms is eventually lost to the abiotic environment

Question 15

Biomass

Answer 15

The total mass of a group of organims

→ has energy

Question 16

Most of the energy in the food that is digested and absorbed by organisms in a tropic level = released by respiration in cell activity
SO what is left for other organisms in higher trophic levels?

Answer 16

Chemical energy in carbs and other C compounds that haven’t been used up in cell respiration

Question 17

Another 2 reasons why not all energy is transferred in successive trophic levels

Answer 17

1) The organisms in a trophic level are not entirely consumes by organisms in the next
2) Not all parts of foods ingested by organisms in a trophic level are digested and absorbed

Question 18

Units for pyramid of energy

Answer 18

kJm^-2yr^-1

energy/unit area (m^2)/yr

Question 19

Carbon fixation

Answer 19

When autotrophs convert carbon dioxide into carbohydrates and other carbon compounds

Question 20

Methanogenesis

Answer 20

Methane is produced fro organic matter in anaerobic respiration by METHANOGENIC ARCHAEANS and some diffuses into the atmosphere

Question 21

3 different groups of anaerobic prokaryotes

Answer 21

1) Bacteria that convert organic matter into a mixture of organic acids, alcohol, hydrogen and carbon dioxide
2) Bacteria that uses the organic acids and alcohol to produce acetate, carbon dioxide and hydrogen
3) Archaeans that produce methane from carbon dioxide, hydrogen and acetate

Question 22

4 different environments that methanogenesis can happen

Answer 22

1) Mud along shores and bed of lakes
2) Swamps, mangrove forests, wetlands where the soil or peat deposits are waterlogged
3) Guts of termites and of ruminant mammals (cattle, sheep)
4) Landfill sites where organic matter is in wastes that have been buried