F215 3 - Ecosystems, Population and Sustainability

Question 1

Anabolism

Answer 1

Type of metabolism: biochemical reactions that synthesise large molecules from smaller molecules. This requires energy/ATP.

Question 2

Autotroph

Answer 2

Organism that makes its own food using simple inorganic molecules, such as carbon dioxide and water, and energy. Photoautotrophs (plants, some protoctists and some bacteria) use light as the source of energy. Chemoautotrophs (some bacteria) use chemical energy.

Question 3

Biodiversity

Answer 3

The number and variety of living things to be found in the world, an ecosystem or habitat.

Question 4

Carrying capacity

Answer 4

The maximum population size that can be maintained over a period of time in a particular habitat.

Question 5

Catabolism

Answer 5

Type of metabolism: biochemical reactions that produce small molecules by hydrolysis of larger molecules.

Question 6

Chemoautotrophs

Answer 6

Chemoautotrophs (some bacteria) are organisms that use chemical energy to makes their own food using simple inorganic molecules, such as carbon dioxide and water, and energy.

Question 7

Community

Answer 7

All the populations of different species that live in the same place at the same time, and who can interact with each other.

Question 8

Competition

Answer 8

A struggle between individuals for resources (like food or water) that are not present in amounts adequate to satisfy the needs of all the individuals who depend on those resources.

Question 9

Conservation

Answer 9

Maintenance of biodiversity, including diversity between species, genetic diversity within species, and maintenance of a variety of habitats and ecosystems.

Question 10

Consumers

Answer 10

Living organisms that feed on other living organisms.

Question 11

Coppicing

Answer 11

Cutting a tree trunk close to the ground to encourage new growth.

Question 12

Decomposers

Answer 12

Organisms that feed on dead organic matter, releasing molecules, minerals and energy that then become available to other living organisms in that ecosystem.

Question 13

Ecosystem

Answer 13

All the living organisms and all the non-living components in a specific habitat, and their interactions.

Question 14

Environmental resistance

Answer 14

The combined action of biotic and abiotic factors that limits the growth of a population.

Question 15

Evolution

Answer 15

The process of gradual change in the inherited traits passed from one generation to the next within a population. It results in the formation of new species.

Question 16

Gene

Answer 16

A length of DNA that codes for one (or more) polypeptides/proteins. Some genes code for RNA and regulate other genes.

Question 17

Gene pool

Answer 17

Total genetic information possessed by the reproductive members within a population of organisms.

Question 18

Genetic drift

Answer 18

Also called allelic drift. The change in allele frequency in a population, as some alleles pass to the next generation and some disappear. This causes some phenotypic traits to become rarer or more common.

Question 19

Habitat

Answer 19

The place where an organism or population of organisms lives.

Question 20

Haploid

Answer 20

Eukaryotic cell or organism having only one set of chromosomes. Denoted by n.

Question 21

Hardy–Weinberg principle

Answer 21

The concept that both genotype frequencies and gene frequencies will stay constant from generation to generation, within a large interbreeding population where mating is random, there is no mutation and no selection or migration.

Question 22

Heterotroph

Answer 22

Organism that gains its nutrients from complex organic molecules. It digests them to simpler, soluble molecules and then respires some of them to obtain energy, or uses the products of digestion to synthesise the organic molecules it needs. Heterotrophs are consumers in food chains. Parasites and saprotrophs are also heterotrophs. Animals, some bacteria and some protoctists are heterotrophs.

Question 23

Isolating mechanism

Answer 23

Mechanism that divides populations of organisms into subgroups.

Question 24

Limiting factor

Answer 24

A variable that limits the rate of a particular process. If the factor is increased then the process will take place at a faster rate. Where the rate of a natural process is affected by a number of factors, the limiting factor is the one whose magnitude limits the rate of the process.

Question 25

Monogenic

Answer 25

Characteristic coded for by one gene.

Question 26

Monophyletic

Answer 26

A monophyletic group is one that includes an ancestral organism and all its descendent species.

Question 27

Mutation

Answer 27

Structural change to genetic material – either to a gene or to a chromosome.

Question 28

Mutualism

Answer 28

A relationship between two organisms from which both benefit.

Question 29

Natural selection

Answer 29

Mechanism for evolution. Organisms that are well adapted to their environment are more likely to survive and reproduce, passing on the alleles for the favourable characteristics.

Question 30

Negative feedback

Answer 30

A process in which any change in a parameter brings about the reversal of that change so the parameter is kept fairly constant.

Question 31

Niche

Answer 31

The role that a species plays in an ecosystem.

Question 32

Nitrogen fixation

Answer 32

Conversion of nitrogen gas into a form which is usable by plants, such as nitrate or ammonium ions.

Question 33

Paraphyletic group

Answer 33

A classification group for living organisms that includes the most recent ancestor but not all of the descendants.

Question 34

Phylogenetic group

Answer 34

Group of organisms that share evolutionary ancestry.

Question 35

Polygenic

Answer 35

Characteristic coded for by many genes. Examples include height and intelligence in humans. Polygenic characteristics are more influenced by environmental factors than are monogenic characteristics.

Question 36

Population

Answer 36

All of the organisms of one species, who live in the same place at the same time, and who can breed together.

Question 37

Population genetics

Answer 37

The study of the gene pools and the allele and genotype frequencies of populations of organisms.

Question 38

Positive feedback

Answer 38

A process in which any change in a parameter brings about an increase in that change.

Question 39

Producers

Answer 39

Autotrophic organisms (plants, some protoctists and some bacteria) that convert light energy to chemical energy, which they then supply to consumers.

Question 40

Productivity

Answer 40

Primary productivity is the rate of production of new biomass by producers. It is the energy captured by their chlorophyll and used to synthesise organic molecules. This minus the energy released via their respiration is the net primary productivity – the energy available to heterotrophs through consumption of producers’ biomass.

Question 41

Quadrat

Answer 41

A square frame used for sampling in fieldwork.

Question 42

Response

Answer 42

The reaction to a stimulus.

Question 43

Saprotrophs

Answer 43

Organisms (like bacteria and fungi) that feed by secreting enzymes onto food, and absorbing digested nutrients across their outer walls.

Question 44

Selection pressure

Answer 44

Environmental factor that confers greater chances of surviving and reproducing on some members of the population than on others.

Question 45

Social behaviour

Answer 45

Behaviour of organisms of a particular species living together in groups with relatively defined roles for each member of the group.

Question 46

Species

Answer 46

The biological species concept is a group of similar organisms that can interbreed and produce fertile offspring. The phylogenetic species concept is a group of organisms with similar morphology, physiology, embryology and behaviour, and that all occupy the same ecological niche.

Question 47

Stabilising selection

Answer 47

A type of natural selection in which the allele and genotype frequency within populations stays the same because the organisms are already well adapted to their environment.

Question 48

Succession

Answer 48

A directional change in a community of organisms over time.

Question 49

Transect

Answer 49

A line taken through a habitat, which helps with systematic sampling of changes across a habitat.

Question 50

Trophic level

Answer 50

The level at which an organism feeds in a food chain.

Question 51

Tropism

Answer 51

A directional growth response in which the direction of the response is determined by the direction of the external stimulus.

Question 52

Vegetative propagation

Answer 52

Asexual reproduction in plants making use of specialised vegetative structures that grow to form new and separate individual organisms.