Chapter 10

Question 1

GIVE FOUR REASONS FOR WHY SPECIES ARE CLASSIFIED.

Answer 1

• For our own convenience
• To make it easier to study
• To make it easier to identify
• To help see the relationship between species

Question 2

DEFINE CLASSIFICATION. WHAT DID CARL WOESE CLASSIFY THINGS INTO?

Answer 2

This study of classification was originally created by carl lineaus who divided every species into 5 kingdoms.
This was further developed by Carl Woese, he categorised the kingdoms into 3 domains: Archaea, Eukaryote, Eubacteria.

Question 3

WHAT ARE THE SEVEN TAXONOMIC CATEGORIES?

Answer 3

• Domain: Largest taxonomic group, split into three: archaea, eubacteria and eukaryote.
• Kingdom: traditionally five: Animals, Plants, Fungi, Protoctista and eukrayotes. These all have a nucleus, those that do not have a nucleus are prokaryotes.
• Phylum: a sub-division of the kingdom. Based on similar body plans.
• Class: a sub-division of the order based on same general traits
• Order: a sub-division of the Phylum based on additional info about the species
• Family: a sub-division of the class based similar genera
• Genus: a group of closely related species
  Species: basic unit of classification

Question 4

WHY IS THE BINOMIAL SYSTEM USED?

WHAT IS THE BIOLOGICAL DEFINITION OF SPECIES?

Answer 4

Using the binomial system gets rid of potential confusion of using common names. These could be different in every country or the same name may be used for a different species. The translation of a certain name in one language may not correspond with the name in another country etc.
The biological definition of species: an organism that can interbreed freely to produce fertile offspring.

Question 5

DESCRIBE FOUR FEATURES OF PROKARYOTIC CELLS.

Answer 5

• No nucleus
• Free floating naked DNA
• No membrane bound organelles
• Smaller ribosomes
  Smaller in size

Question 6

DESCRIBE THREE FEATURES OF PROTOCTISTA

Answer 6

• Eukaryotic
• Mostly single celled
• Wide variety of forms
  Autotrophic and heterotrophic

Question 7

DESCRIBE THREE FEATURES OF FUNGUS

Answer 7

• Eukaryotic
• Single celled or has mycelium made of hyphae
• Saprophytic feeders
  Walls made of chitin

Question 8

DESCRIBE FOUR FEATURES OF PLANTAE

Answer 8

• Eukaryotic
• Multicellular
• Autotrophic feeders
• Walls made of cellulose
  Contain chlorophyll

Question 9

DESCRIBE THREE FEATURES OF ANIMALIA

Answer 9

• Eukaryotic
• Multicellular
• Heterotrophic
  Able to move around

Question 10

WHAT IS EVIDENCE USED FOR IN CLASSIFICATION?

Answer 10

It can be hard to see how closely related we are to certain species because they can be very closely related and look very similar with similar evolutionary aspects. Sometimes, species may not be very closely related but develop similar adaptations - convergent evolution.

Question 11

HOW IS CYTOCHROME C USED IN CLASSIFICATION?

Answer 11

• This a protein present in all respiring animals. They have different chains of amino acids based on the adaptations. This cytochrome C of different animals can be tested, if the makeup is very similar then it can be concluded that the two are more closely related. If there is one or two differences then there is a fairly close relation but if there are ten, fifteen then the relation is quite far.

Question 12

HOW IS DNA USED IN CLASSIFICATION?

Answer 12

• DNA is the same in all organisms. The same code of amino acids will code for the same characteristic in bacteria and in an animal. Mutations can occur randomly in DNA leading to genetic variation. The DNA of a species can be studied to see its similarities and differences to other species. This can be used to see how closely related two species are. This method is very accurate.

Question 13

WHAT SYSTEM DID CARL WOESE DEVISE AND FOR WHAT REASON?

Answer 13

He split prokaryotes into Archaea and Bacteria. This is because Bacteria is different structurally to Archaea and Archaea has some similarities to Eukaryotes.
Differences in Archaea:
- Different mechanisms for DNA replication
- Different RNA
- Different cell membrane structure
- Different structure of internal flagella
- No proteins bound to their genetic material

Question 14

Classification

Answer 14

• Artificial: placing things into groups for convenience. For example, sorting flowers by colours in a gardening book. This has limited information, is based on limited characteristics, is stable and does not reflect evolutionary relationships.
  
  • Natural: this is done for other purposes such as knowing which species are endangered so you don’t do studies on the. These provide detailed information, involve many characteristics, show the evolutionary relationships and can change according to new information.

Question 15

Phylogeny

Answer 15

Phylogeny considers the evolutionary aspects of different species. It assumes that all species have a common ancestor somewhere. The closer this common ancestor is will determine how closely related the two species are. Phylogeny can be used to see how exactly two species are related and where this relationship stems from. It is done using a phylogeny tree.

Question 16

Darwin

Answer 16

Darwin found that there was a struggle to survive so those who were better adapted to survive - because everybody is born different - will survive longer so have greater chance of reproducing. Darwin concluded that there is a struggle to survive, and only those adapted to survival will survive.

Question 17

Fossils

Answer 17

Fossils provide evidence that old species which are different to those present now once existed. It also shows that these old species evolved into new species. New species were often similar to old species.

Question 18

Variation

Answer 18

Variation is the differences that arise in species as a result of changes in DNA or environmental factors. These can be within the species or between species.
- Intraspecific: happens within a species such as eye colour
- Interspecific: happens between species and usually sets the species aside from the rest.
Variation can occur for two reasons:
- Genetic: the genes that we inherit from our parents are unique to us and no two organisms will have the same DNA. This results in variation such as eye colour differences.
- Environmental: the environment that we live in can result in differences for example, a person’s skin may become darker because they live in a hot country.

Question 19

STANDARD DEVIATION:

Answer 19

this is a measure of variation of how spread it is from the mean.
If a normal distribution is shown then:
• 68% should be within the normal range
• 95% on the majority
• Anything on the 5% remaining is anomalous or abnormal.

Question 20

STUDENTS T-TEST

Answer 20

this compares two means and sees if the difference is significant.

The whole point of statistical testing is to see if its significant. The degrees of freedom are usually calculated by: (sample size - number of data sets) . Then you read this degree of freedom level of a table and correlate to the 5%. If the answer is more then the results are significant.

Question 21

SPEARMAN’S RANK

Answer 21

considers the relationship between two sets of data. This tells us wether two sets of data are corelated or not.

This can be correlated against a critical values table. if the value is lower then there is no significance and the results are not correlational.

Question 22

Continuous data

Answer 22

two extreme values with intermediate values. Best plotted on a histogram. For example, height.

Question 23

Discontinuous data

Answer 23

only has est values for set categories. Best plotted on a bar chart. For example, gender.

Question 24

Adaptations

Answer 24

any characteristic that helps an organism survive in its habitat. These can be to find food and water, to defend against predators, to mate etc. there are three types:

Question 25

MARRAM GRASS

Answer 25

• Physiological: Marram grass can roll up its leaves more tightly to make water loss harder, this is done when cells lose turgidity so leaves roll tightly. Guard cells operate the same way. Contains many lignified cells to keep the cell upright when water is lost losing turgidity.
  
  • Biological: earthworms have no eyes so don’t know what is touching them. When they are touched they contract and retreat back into their burrow.
  • Anatomical: Marram grass is a xerophyte adapted to live in sand with very little water. They have long roots, curled leaves, stomata in pits, thick waxy layer on upper dermis etc. all these help the plant survive.

Question 26

MOLES

Answer 26

both marsupial and placental moles, despite not being related, share a lot of physical characteristics.
- Anatomical: cylindrical body, small eyes and strong front legs. Large claws, short fur, short tails and a nose with tough skin.

Question 27

Natural Selection

Answer 27

• A mutation occurs in a gene forming an allele
  
  • Once this variety exists if the adaption allows the organism to survive better there is more chance of it reproducing.
  • The more offspring that contain this allele the better adapted they will be at surviving
  • They will become the dominant species as the others die out due to insufficient adaptations

Question 28

Pesticide resistance

Answer 28

Insects can kill crops and ruin harvests. Humans use insecticides to kill these however, insects can become immune to these insecticides. When these become resistant they will be eaten by their predators who receive a high dose of this insecticide, this can then travel up the food chain and often end up in humans.

Question 29

Antibiotic resistance

Answer 29

This occurs when people take antibiotics. The antibiotic will kill the bacteria but some will survive. As most of the bacteria are gone the individual will feel better and stop taking antibiotics. The resistant bacteria will divide and be stronger than before. It will be harder for antibiotics to kill this. Finish your antibiotic course.