Biology: Topic 4

Question 1

Biodiversity

Answer 1

The variety of organisms within an ecosystem.

Question 2

Species

Answer 2

A group of organisms that can interbreed to produce fertile offspring. They will have similar morphology, physiology and behaviour.

Question 3

Habitat

Answer 3

Where an organism lives. Different habitats have specific conditions.

Question 4

Population

Answer 4

A group of interbreeding organisms of the same species in the same area.

Question 5

Community

Answer 5

The combination of all the various populations within a habitat.

Question 6

Niche

Answer 6

The way an organism exploits it’s environment. Food source, shelter, time of feeding, etc.

Question 7

Adaptation

Answer 7

A feature that helps an organism survive in it’s environment and exploit their specific niche. Can be behavioural, physiological or anatomical.

Question 8

Adaptation: Behavioural

Answer 8

Behavioural adaptations of organisms are any action that is carried out by an organism.

Question 9

Adaptation: Physiological

Answer 9

Physiological adaptations involve the internal mechanisms of an organism.

Question 10

Adaptation: Anatomical

Answer 10

Anatomical adaptations are the physical structures of an organism.

Question 11

Co-adaptation

Answer 11

When species adapt at the same time to become dependant on one another.

Question 12

Evolution by Natural selection

Answer 12

Organisms better adapted to survive selection pressures will reproduce and pass on their genes, whereas other organisms will die.

Question 13

Selection pressure

Answer 13

Factors that require a population to adapt in order to survive.

Question 14

Conditions required for evolution by natural selection

Answer 14

Genetic variation within the population
Selection pressures
Reproduction must be occuring

Question 15

Gene pool

Answer 15

Contains all the alleles of all the genes present in a population.

Question 16

Reproductive isolation

Answer 16

Reproductive isolation can occur by the formation of a gene pool barrier, which can occur by geographical, temporal, behavioural or mechanical isolation.

Question 17

Geographical isolation

Answer 17

Geographical isolation occurs when some organisms of the population become separated geographically.

Question 18

Temporal isolation

Answer 18

Temporal isolation involves some organisms of the species reproducing at different times.

Question 19

Behavioural isolation

Answer 19

Behavioural isolation means that the behaviours of some organisms in the population do not attract other organisms.

Question 20

Mechanical isolation

Answer 20

Mechanical isolation is when some individuals evolve to be different shapes and sizes .

Question 21

Speciation

Answer 21

When adaptations to some organisms in a population cause them to be unable to reproduce and produce fertile offspring with the non adapted organisms. Thus they have become a new species.

Question 22

Hierarchy of classification

Answer 22

1. Kingdom
   
   2. Phylum
   3. Class
   4. Order
   5. Family
   6. Genus
   7. Species

Question 23

Scientific name for an organism

Answer 23

First the name of it’s genus, then the name of it’s species.

Question 24

Phylogenetic tree

Answer 24

Phylogenetic trees can be used to show evolutionary relationships between different organisms. They show how each organism has adapted and can show which species have common ancestors.

Question 25

Phenotypic traits

Answer 25

Observable characteristics, e.g., looks and behaviours.

Question 26

Convergent evolution

Answer 26

Unrelated organisms evolving a similar appearance or behaviours as they adapt to the same conditions.

Question 27

Genotype

Answer 27

Combination of all the organism’s alleles.

Question 28

Genetic diversity

Answer 28

The number of different genotypes.

Question 29

Species richness

Answer 29

The number of species present in a habitat.

Question 30

Species eveness

Answer 30

How similar the populations of all of the different species in the habitat are.

Question 31

Simpsons diversity index

Answer 31

D = N(N-1)/Σn(n-1)

N = The total number of individuals from all the species.
n = The total number of individuals from a particular species.

Question 32

Cellulose

Answer 32

A long, unbranched polysaccharide made from beta glucose molecules bonded together by 1-4 glycosidic bonds.

Question 33

Microfibrils

Answer 33

Cellulose chains join together by forming hydrogen bonds. Microfibrils are joined together by cross linking polysaccharide chains (hemicellulose and pectin).

Question 34

Plasmodesmata

Answer 34

Gaps in cell walls to allow adjacent cells to have one continuous cytoplasm.