Classification and Evolution Flashcards
(27 cards)
1
Q
What is classification?
A
-Process by which we allocate living things to groups of similarity
2
Q
What is phylogeny
A
- 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)
3
Q
What is taxonomy?
A
- Study the principles of classification
- Differences between species
- Species usually grouped according to physical similarities
(species similar are placed together)
4
Q
Why do we classify things?
A
- To order them
- For our convenience
- To make studying them easier
- To make identification easier
- To help us to see relationships
5
Q
Current classification system
A
- As you rise through hierarchy, more variation is shown
- Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
6
Q
What are the 5 kingdoms?
A
- Prokaryote
- Protoctista
- Fungi
- Plantae
- Animalia
7
Q
What is discontinuous variation?
A
- 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
8
Q
What is continuous variation?
A
- 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
9
Q
Genetic causes of variation
A
- 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
10
Q
Environmental causes of variation
A
- Sunbathing causes darkening of skin
- Lack of a balanced diet causes poor growth
- Growing a plant in Mg deficient soil results in yellow leaves
11
Q
3 Adaptations of organisms to their environment
A
- Behavioral
- Physiological
- Anatomical
12
Q
What is an adaptation?
A
- Any heritable trait that helps an organism (plant, animal, survive and reproduce in its environment)
- Passed onto offspring
13
Q
What are behavioral adaptations?
A
- 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
14
Q
What are anatomical adaptations?
A
- Physical features (Internal and external)
- Structural adaptation (e.g. many bacteria have flagella to move)
15
Q
Physiological adaptations
A
- Processes that take place inside an organism (correct cell functioning)
e.g. reflexes, blinking and temperature regulation
16
Q
How natural selection works?
A
- 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
17
Q
What are selective forces?
A
- Availability of suitable food
- Predators
- Diseases
- Physical and chemical factors
18
Q
What is speciation?
A
- 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
19
Q
How does speciation happen?
A
- Reproductive barrier must be present
- Organisms are unable to breed with others in their group
- Beneficial variations are spread through reproduction
20
Q
Allopatric reproductive barriers
A
- Geographical separation
- Physical separation prevents effective interbreeding
e.g. earthquakes, flooding
21
Q
Sympatric Reproductive Barriers
A
- Reproductive barrier within the population
- Physical, social or biochemical change
- Prevents one member from breeding with another
22
Q
Genetic causes of variation
A
- Alleles
- Mutations
- Meiosis (independent assortment and crossing over)
- Sexual reproduction
- Chance
23
Q
What is interspecific variation
A
Difference between organisms within a species
24
Q
What 3 pieces of evidence are there for evolution?
A
- Paleontology (study of fossils and fossil records)
- Comparative anatomy (study of similarities + differences between organisms anatomy)
- Comparative biochemistry (similarities + differences between organisms chemical makeup)
25
Advantages to phylogeny classification
- Continuous tree, organisms are not put into groups that they don't quite fit into)
- Allow different degrees of biological differentiation
26
3 Domain system
- Bacteria
- Archaea
- Eukarya
27
What were Darwin's observations?
- 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
