Classification and evolution Flashcards
Taxonomic (linnaean) classification
(do keep pond clean or frog gets sick)
Domain, kingdom, phylum, class, order, family, genus, species
Phlyum- similar characteristics
Class- mammals, birds, reptiles…
Why binomial nomenclature (using genus and species) used instead of common names
- More than 1 common name
- Shows genus
- Binomial nomenclature is consistent- can be used by scientists everywhere
Why is classification used?
- to identify evolutionary links
- to predict certain characteristics
- to identify species
Differences between artificial classification and natural classification
Artificial (based on observable characteristics)
- uses only physical characteristics
- does not show evolutionary relationships
- does not change
Natural (based on evolutionary relationships)
- uses many characteristics such as physiology, biochemistry
- Shows evolutionary links
- changes as knowlege advances
5 kingdoms
3 domains
differences between 3 domains
Who made the 3 domain system
- Animalia, Plantae, Fungi, Protoctista, Prokaryotae
- Animalia, Plantae, Fungi, Protoctista, eubacteria, archaebacteria
- eukarya, archae, bacteria
Bacteria
- peptidoglycan cell wall
- 5 proteins in RNA polymerase
- 70S ribosomes
Archae
- no peptidoglycan cell walls
- 8-10 proteins
- 70S ribosomes
Eukarya
- No peptidoglycan cell walls
- 12 proteins
- 80S ribosomes
Observable feature of different kingdoms:
- Animalia
- Plantae
- Fungi
- Protoctista
- Prokaryotae
Animalia
- Multicellular
- Membrane bounds organelles
- Heterotrophic
- Mechanisms of motion: cilia, flagella, contractile muscles
Fungi
- unicellular or multipcellular
- saprophytic
- membrane bound organelles
- no mechanism of motion
- chitin cell wall
- threads of hyphae in body
Plantae
- multicellular
- membrane bound organelles
- autotrophic
- no mechanism of motion
- chloroplasts
- cellulose cell wall
- store food as starch
Prokaryote
- unicellular
- no membrane bound organelles
- flagella (flagellin)
- no mechanism of motion
- saprophytic
Protoctista
- unicellular
- membrane bound organelles
- heterotrophic or saprophytic
- chloroplasts
What is phylogeny
Benefits of phylogony compared to classification
What is is called when organisms of different species come from same species (other than divergent evolution)
Phylogeny is the evolutionary relationships between organisms and how closely related they are.
Phylogeny uses a continuous tree, classification uses discrete taxanomical groups.
taxanomic classification hints thta all organisms in a rank are equal.
Monophyletic species
Variation affected by:
Environmental or genetic factors
Causes of genetic variation
Environmental causes of variation
- mutation- change in DNA sequence causes chage in protein which affects physical and metabolic characteristics
- Meiosis- independent assortment, crossing over
- Random fertilisation- random sperm fertilises egg so random combination of genetic material
- Sexual reproduction- offspring inherits genes from mother and father, creates different allles
Climate, diet, lifestyle
What is:
continuous variation
Discontinuous variation
Continuous variation- characteristic that can take any value within a range
DIscontinuous variation- Characteristic that can only result in certain set values.
More about continuous and discontinuous variation
Continuous
- caused by many genes (polygenic)
- caused by genetic and environmental factors
- Bell curve, scatter graph, histogram
Discontinuous
- caused by single gene
- Caused by just genetic factors
- Pie chart, bar chart
What are adaptations
Types
Characteristics that increase an organisms chance of survival
Behavioural
Anatomical
Physiological (biochemical)
Marram grass adaptations:
Behavioral
Anatomical
Physiological
Behavioral:
- Stomata close and leaf rolls tighter in water shortage
- Plant grows when covered in sand
Anatomical:
- Waxy cuticle
- Curled leaves
- Hair leaves
-folded to create pits for stomata
Physiological
- Lignified cells
- Guard cells
Moles showing convergent evolution
Placental and Marcupial mole
- streamlined
- Velvety fur
- No eyes
- Modified forelimbs
Selectional pressure process
Examples of selectional pressure
Factors that affect an organisms chance of survival and ability to reproduce.
-Organisms in a species show variation due to alleles.
- Organisms with advantageous allele are better adapted to selectional pressure and more likely to survive and reproduce. (‘survival of the fittest’)
- The advantageous allele is passed down to offspring and process is repeated, until greater proportion of individual with adv. allel.
- Frequency of adv. allele increases in species gene pool
competition, disease, predation
What did Darwin and Wallace do
Charles Darwin went to the Galapagos to study finches’ beak size.
Wallace’s work made him realise some processes occur over long periods of time.
Evidence for evolution
Fossils
- Show extinct species
- Show timeline- simple life developed before more complex
- Shows ecological links e.g., plants before animals
- Shows evolutionary links- common ancestors
However,:
- some creatures are soft-bodied so dont have bones- cant form fossils
- Some fossils are destroyed
- Fossils only form under certain conditions
Comparative anatomy
- Homologous structures (appear different but have same underlying structure)
- e.g., pentadactyl limb
- evidence for divergent evolution
Comparative biochemistry
(sim. & diff. in proteins that control life processes)
- cytochrome C is a highly conserved protein containing may amino acids. Some neutral changes can occur where amino acids change.
- By comparing amino acid sequencing or order of NA bases, we can see how similar species are.
Changes due to selective pressures can be:
Stabilising
Directional
Disruptive
Factors affecting evolution
Sexual selection (increase in frequency of genes that code for characteristics that increase mating success)
Natural selection (increase in frequency of advantageous genes that icrease chances of survival)
Mutations (random changes to base pairing, causes different, new genes)
Gene flow (introduction or removal of specific genes from a population due to emigration or imigration)
Genetic drift (opp. to natural selection: small populations, due to CHANCE)
Hardy Weinburg equations only occur when
All agents of evolutionary change are removed.
- large population
- no mutations
- No imigration, emmigration (no gene flow)
- no natural selection
- no random mating (sexual selection)
Speciation definition
Types
Formation of 2 different species from 1 through process of evolution
Allopatric
- physical barrier between species
- different selective pressures
- different advatageous allele passed to offspring
- over time, frequency of alleles and characteristics so different
Sympatric
- random mutations occur
- reproductive isolation- unable to mate together
due to:
- temporal
- behavioral
- structural
- ecological
- gamete mortality (sperm doesn’t meet/ penetrate egg)
- Hybrid inviability (fertilisation occurs but embryo doesn’t develop)
- Hybrid sterility (offspring is sterile)
What is artifical fertilisation (aka selective breeding)
Examples
breeding animals together with deireable characteristics
Cows with high milk yield
Bread wheat with high wheat yield
- select female and male and breed together
- select offspring with highest yiel
- breed together
- continue cycle
Problems with artificial selection (selective breeding)
Reduction in gene pool (low genetic diversity)
- More susceptible to genetic/ heriditary diseases
- Means less resistant to disease/envioronmental changes
- Less likely to evolve (extinction)
- Useful alleles may be lost from population
Reasons to maintain viable species
- genetic variation (increase genetic biodiversity)
- source of useful alleles
- source of replacement if cultivated population is in danger
