Classification and evolution

Question 1

What is genetic variation?

Answer 1

Due to the diversity of alleles present in the gene pool.

Question 2

What is environmental variation?

Answer 2

Environmental conditions affect the way gene expressed in the phenotype.

Question 3

What is interspecific variation?

Answer 3

The differences between any 2 species.

Question 4

What is intraspecific variation?

Answer 4

The differences between members of the same species.

Question 5

What is continuous variation?

Answer 5

There are 2 extremes and a full range of values in between. Smooth radiation on a histogram and is quantitative. eg. leaf size, height.
Polygenic and environmental effects.

Question 6

What is discontinuous variation?

Answer 6

Discrete phenotypes - 2 or more categories which do not overlap.
Qualitative with no intermediates. eg. blood type, seed shape.
Monogenic. Genes at different loci can interact to influence 1 characteristic.

Question 7

What is natural selection?

Answer 7

How features of the environment apply a selective force on reproduction of individuals in a population.

Question 8

What is the process of natural selection?

Answer 8

1. random genetic mutations creates multiple alleles
2. genetic variation -> intraspecific competition
3. certain alleles are advantageous to environmental challenges
4. selection pressures occur. Some alleles will survive more as they can live and reproduce
5. frequency of advantageous allele increases

Question 9

What were Darwin’s 4 observations?

Answer 9

Offspring appear similar to parents.
No 2 individuals are fully identical.
Organisms can produce many offspring.
Populations in nature tend to remain a fairly stable size.

Question 10

What is the fossil record?

Answer 10

Old and new species are often similar - modern had variations making them better adapted to environment.
Evolution documented in fossil records - evidence for natural selection.

Question 11

What is modern evidence for evolution?

Answer 11

Some molecules/biological structures are found in most of the living world, suggesting a common ancestor.
DNA structure can be analysed for evolutionary relationships - compare genes by sequencing DNA bases.
DNA + biological molecules differ less between species with recent common ancestor.

Question 12

What is mitochondrial DNA?

Answer 12

mDNA - inherited from egg during sexual reproduction - only from mother. Can trace maternal history to mitochondrial Eve.

Question 13

Why does mDNA have a lot of variation between individuals?

Answer 13

It mutates more often than nuclear DNA and does not have same checkpoints in place. Has been used to solve uncertainties about origin of certain races.

Question 14

What is a species?

Answer 14

Contains all organism that are capable of breeding to produce fertile offspring.

Question 15

Why is classification needed?

Answer 15

• make studying living things more manageable
• easier to identify organisms
• scientists can study relationships between species
• easier to identify new species

Question 16

What did Linnaeus do?

Answer 16

Classifies all known organisms into categories as a hierarchy:
Domain - Eukaryotae, Archeae and Bacteria
Kingdom - Animalia, plantae, fungi, protoctists, prokaryota
Phylum
Class
Order
Family
Genus
Species

Question 17

What is binomial naming?

Answer 17

Uses genus and species names to avoid confusion when naming species.
Always underlined/italics, genus with capital letter.

Question 18

What are features of an artificial classification?

Answer 18

Stable, based on few characteristics, doesn’t reflect evolutionary relationships, provides limited information.

Question 19

What are features of a natural classification?

Answer 19

Uses many characteristics, reflects evolutionary relationships, may change with advancing knowledge.

Question 20

What is a phylogenetic species?

Answer 20

A group of organisms which are very similar in appearance, anatomy, physiology, biochemistry and genetics.

Based on evolutionary relationships with homologous characteristics.

Question 21

What is a phylogenetic tree diagram?

Answer 21

• branch type = species at end of lineage
• branching points = common ancestors
• organisms belonging to same phylogenetic group = monophyletic
• common ancestors not alive, so just say shared ancestor
• closer the branches, closer the evolutionary relationship

Question 22

What is Cytochrome C?

Answer 22

A respiratory protein, but not identical in all species. Comparing amino acid sequence can help evaluate evolutionary relationships.
Same = closely related.

Question 23

What is DNA analysis used for?

Answer 23

Biological molecule in all living organisms. Genome sequencing to assess genetic diversity based on genetic similarity.

Most accurate.

Question 24

What are structural differences between bacteria and the 2 other domains?

Answer 24

Bacteria have different cell membrane structure and have no membrane bound organelles.
Have flagella
Different enzymes for RNA synthesis.
Single loop of naked DNA
Different mechanisms for DNA replication + RNA synthesis.

Question 25

What are shared features between Archeae and Eukarya?

Answer 25

Similar enzymes for RNA synthesis.
Similar DNA replication + RNA synthesis mechanisms.
Cell wall not made of peptidoglycan.
Production of proteins which bind to DNA eg. histones.

Question 26

What are features of Animalia?

Answer 26

Eukaryotic, multicellular, heterotrophic, can move around.

Question 27

What are features of Plantae?

Answer 27

Eukaryotic, multicellular, surrounded by cellulose cell wall, autotrophic so cells have chlorophyll.

Question 28

What are features of Fungi?

Answer 28

Eukaryotic, single/multicellular, chitin cell wall, multinucleate cytoplasm, saprotrophic.

Question 29

What are features of Protoctists?

Answer 29

Eukaryotic, can have animal/plant like features, mostly free living, most single celled. Can be autotrophic or heterotrophic.

Question 30

What are features of Prokaryote?

Answer 30

No nucleus and no membrane bound organelles, naked loop of DNA, smaller ribosomes, free living/parasitic.