4.2.2 Classification and Evolution COMPLETE Flashcards
DEFINITION- Classification
Used to group life on earth, using the similarities and differences between organisms. Relies on observation but also molecular evidence
DEFINITION- Phylogeny
The study of evolutionary relationships between species
DEFINITION- Evolution
The process of gradual change that occurs in living organisms
DEFINITION- Natural Selection
The mechanism that drives evolution
DEFINITION- Continuous Variation
When they lie within a range, i.e. height
DEFINITION- Discontinuous Variation
When somethings either one thing or another, i.e. eye colour
DEFINITION- Interspecific Variation
Variation between species
DEFINITION- Intraspecific Variation
Variation between individuals of the same species
DEFINITION- Divergent Evolution
Process where the same common ancestor evolves differently leading to different species being created
DEFINITION- Convergent Evolution
The evolution of similar features in distantly related species, traits that are selected by the environment. Will have similar ecological niches
DEFINITION- Adaption
A feature that enhances survival and long term reproductive success
DEFINITION- Anatomical adaptions
Any structure that enhances the survival of the organism
DEFINITION- Behavioural adaptions
Any aspect of behaviour that allows organisms to survive where it lives
DEFINITION- Physiological adaptions
Ensures the correct functioning of cell processes
DEFINITION- Analogous Structures
Structures that have similar form or function, but have evolved separately
DEFINITION- Normal Distribution
Symmetrical bell shaped graph
DEFINITION- Species
A group of organisms very similar in appearance, anatomy, physiology, biochemistry and genetics that can breed together and produce fertile offspring
Order of Taxonomic Groups
Domain Kingdom Phylum Class Order Family Genus Species (Dirty kinky pigs can only fly going sideways)
Binomial System
First word= Genus, Capital letter
Second word= Species, Lowercase
Must be in italics or underlined
The five kingdoms
- Prokaryote
- Protoctists
- Fungi
- Plants
- Animals
Prokaryotes
- No nucleus
- Loop of DNA
- No membrane bound organelles
- Smaller cells
- Peptidoglycan cell walls
Protoctists
- Eukaryote
- Mostly single celled
- wide variety of forms so underlying features don’t match
- Mostly free living
- Autotrophic/ heterotrophic
Fungi
- Eukaryote
- Cell walls made of Chitin
- Mostly free living, single cells
- Saprophytic nutrition
- Store food as glycogen
Plants
- Eukaryotes
- Multicellular
- Cellulose cell wall
- Autotrophic nutrition
- Contain chlorophyll and store food as starch
Animals
- Eukaryotes
- Multicellular
- Heterotrophic nutrition
- Usually move around and store food as glycogen
Heterotrophic Nutrition
Digest larger organic molecules to form smaller ones for absorption
Cytochrome C
All respiring organisms use Cytochrome C but the protein code is not the same. By comparing the amino acid sequence you can find the evolutionary distance of species.
DNA/RNA for classification
DNA sequences change due to mutations, the more differences found indicates more evolutionary distance
The Three domains
- Eukarya
- Archaea
- Bacteria
Archaea
More closely related to eukaryotes than Bacteria but still belong to the Prokaryotes.
Eukarya
All life except Prokaryotes, share characteristics such as having a nucleus.
Phylogenetic Tree
Displays the evolutionary relationship between species, the closer they appear the more related they are, converging lines means they share a common ancestor.
Why is variation important
Maintains ecosystems, reduces chance of genetic defects, allows evolution, better chance to cope with environmental changes
Causes of Genetic Variation
- Alleles
- Mutations
- Meiosis
- Sexual Reproduction
- Chance
Alleles on Genetic Variation
Genes have different alleles so can produce different effects. Individuals may inherit different alleles
Mutation on Genetic Variation
Changes to the DNA sequence can lead to changes in the proteins and consequently different physical and metabolic characteristics
Meiosis on Genetic Variation
Gametes are produced by meiosis and each one receives half its contents form each parent. Genetic material is mixed up by independent assortment and crossing over
Sexual Reproduction on Genetic Variation
Offspring form two individuals inherit genes from each parent.
More variation with organisms that sexually reproduce
Chance of Genetic Variation
All gametes produced from parental genome are different.
All offspring contain a unique combination of genetic material.
Genotype
The combination of alleles in an organism
Phenotype
Characteristics seen in an organism
Standard Deviation
Calculates the dispersion of data
Spearman’s Rank
Used to work out if a correlation is statistically significant, answers will range from +1 to -1, closer to 0 means less correlation
Three Categories of Adaption
- Behavioural
- Anatomical
- Physiological/ Biochemical
Marram Grass Adaptions
Anatomical- Long roots, pitted stomata, thick waxy cuticle, curled leaves
Behavioural- Closing stomata, quick growth
Physiological- Guard cells opening & closing stomata, Lower water potential as salty conditions
Evidence for Evolution
- Fossil Record
- Modern Evidence
- Darwins Natural Selection
Fossil Record
Show as species get more complex as well as the extinction and arrival of life forms. Used to form Phylogenetic trees.
PROBLEM- soft tissue decays, tectonic plates cause damage, not all found so still incomplete
Modern Evidence
Looking at Biological molecules, Protein variation and DNA sequencing
Darwins Deductions
- Since most offspring don’t survive (large numbers produced) there must be a struggle for survival/ competition.
- The ones with characteristics enabling survival and reproduction will pass on the characteristics.
How natural selection works
- The resources needed for survival are limited
- Some varieties have a better chance of survival, so they reproduce and pass on alleles.
- Therefore greater proportion of the next generation will have those genes
- Over many generations the species become better at surviving and the ‘best’ features are naturally selected
Selection pressures
Individuals don’t adapt, the population does.
The environmental feature that selects the individuals advantageous gene is the selection pressure.
i.e. food availability, predation, climate
Pesticide Resistance
Humans create a selection pressure by using pesticides, the resistance develops in different ways:
- Insects become able to metabolise insecticide
- Target receptor on the cell membrane is modified
Problems with Pesticide Resistance
- More insects means more disease as they carry them
- Becomes more concentrated on the food chain as those who survive the pesticide are eaten by predators and pass it on (Bioaccumulation)
- Crop loss
Devils Face Tumour Disease
A tumour that is spread when hosts bite each other, a cancer fighting genome is quickly being developed to cope with the selection pressure. Therefore the Devils are quickly adapting to survive the cancer.
