Classification and Evolution

Question 1

What is classification?

Answer 1

-Process by which we allocate living things to groups of similarity

Question 2

What is phylogeny

Answer 2

• It is the study of evolutionary relationships between organisms
• How closely related groups of organisms are
• Species that belong to the same phylogenetic group are called monophyletic (humans and gorillas)

Question 3

What is taxonomy?

Answer 3

• Study the principles of classification
• Differences between species
• Species usually grouped according to physical similarities
  (species similar are placed together)

Question 4

Why do we classify things?

Answer 4

• To order them
• For our convenience
• To make studying them easier
• To make identification easier
• To help us to see relationships

Question 5

Current classification system

Answer 5

• As you rise through hierarchy, more variation is shown
• Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Question 6

What are the 5 kingdoms?

Answer 6

• Prokaryote
• Protoctista
• Fungi
• Plantae
• Animalia

Question 7

What is discontinuous variation?

Answer 7

• 2 or more distinct categories
• No intermediate values
• Members may be evenly distributed between different forms
• Nearly always caused by genes, little to no environmental influence
• Very few alleles are involved

Question 8

What is continuous variation?

Answer 8

• 2 extremes
• Full range of intermediates
• Most individuals are close to the mean values
• Number of individuals at extremes is low
  (Height, Length of leaves)
• May be cause by genes and environment acting together

Question 9

Genetic causes of variation

Answer 9

• Independent assortment of chromosomes
• Crossing over, exchanging of alleles between homologous chromosomes
• Variation caused by fertilisation during sexual reproduction
• Origin of genetic variation are mutations

Question 10

Environmental causes of variation

Answer 10

• Sunbathing causes darkening of skin
• Lack of a balanced diet causes poor growth
• Growing a plant in Mg deficient soil results in yellow leaves

Question 11

3 Adaptations of organisms to their environment

Answer 11

• Behavioral
• Physiological
• Anatomical

Question 12

What is an adaptation?

Answer 12

• Any heritable trait that helps an organism (plant, animal, survive and reproduce in its environment)
• Passed onto offspring

Question 13

What are behavioral adaptations?

Answer 13

• Helps the organism to survive
  (e.g. earthworms rapidly withdraw when touched)
• Can be innate (instinctive) : ability inherited through genes
• Can be learned : from experience or observing other animals

Question 14

What are anatomical adaptations?

Answer 14

• Physical features (Internal and external)
• Structural adaptation (e.g. many bacteria have flagella to move)

Question 15

Physiological adaptations

Answer 15

• Processes that take place inside an organism (correct cell functioning)
  e.g. reflexes, blinking and temperature regulation

Question 16

How natural selection works?

Answer 16

• Gene mutates to create a new allele
• Mutated allele is beneficial to the organism
• Members of the population/species with this mutation more likely to survive + reproduce
• Mutated allele becomes more common as passed (inheritance)
• Overall, population becomes better adapted to ecosystem for survival

Question 17

What are selective forces?

Answer 17

• Availability of suitable food
• Predators
• Diseases
• Physical and chemical factors

Question 18

What is speciation?

Answer 18

• Formation of new species from existing one
• Long and slow process
• Accumulation of charges
• Individuals can no longer breed to produce viable offspring
• Larger organisms tend to take longer

Question 19

How does speciation happen?

Answer 19

• Reproductive barrier must be present
• Organisms are unable to breed with others in their group
• Beneficial variations are spread through reproduction

Question 20

Allopatric reproductive barriers

Answer 20

• Geographical separation
• Physical separation prevents effective interbreeding
  e.g. earthquakes, flooding

Question 21

Sympatric Reproductive Barriers

Answer 21

• Reproductive barrier within the population
• Physical, social or biochemical change
• Prevents one member from breeding with another

Question 22

Genetic causes of variation

Answer 22

• Alleles
• Mutations
• Meiosis (independent assortment and crossing over)
• Sexual reproduction
• Chance

Question 23

What is interspecific variation

Answer 23

Difference between organisms within a species

Question 24

What 3 pieces of evidence are there for evolution?

Answer 24

• Paleontology (study of fossils and fossil records)
• Comparative anatomy (study of similarities + differences between organisms anatomy)
• Comparative biochemistry (similarities + differences between organisms chemical makeup)

Question 25

Advantages to phylogeny classification

Answer 25

• Continuous tree, organisms are not put into groups that they don’t quite fit into)
• Allow different degrees of biological differentiation

Question 26

3 Domain system

Answer 26

• Bacteria
• Archaea
• Eukarya

Question 27

What were Darwin’s observations?

Answer 27

• Offsprings generally appear similar to their parents
• No two individuals are identical
• Organisms have the ability to reproduce large numbers of offspring
• Populations in nature tend to remain fairly stable in size