Classification and Evolution (4.2.2) Flashcards
Why do scientists classify organisms?
To identify species
A clearly defined system allows the species an organism belongs to be easily identified.
To predict characteristics
If a number of individuals in a group have a specific characteristic, it’s likely that another species in the group will have the same characteristic.
To find evolutionary links
Species in the same group probably share characteristics as they have evolved from a common ancestor.
What is phylogeny?
The study of the evolutionary history of groups of organisms.
How have classification systems changed?
Once based on observable features.
Now includes:
Molecular evidence
Similarities in parts of DNA base sequences of genes.
Similarities in the sequence of amino acids in proteins. e.g. Cytochrome C - a short protein found in many species.
Embryological evidence (similarities in the early stages of development)
Fossil evidence
How does the 3 domain system differ from the 5 kingdom system?
The 5 kingdoms were Prokaryotae, Protocista, Fungi, Plantae, Animalia
The Prokaryotae kingdom is now separated into Bacteria and Archaea domains.
What observations were used in the original classification of organisms?
Anatomical e.g. number of legs
Behavioural e.g. whether an organism lives in groups
What evidence led to the reclassification of Prokaryotae into two domains?
Molecular Evidence
RNA Polymerase is different in Bacteria and Archaea
Archaea, but not bacteria, have similar histones to Eukarya
Cellular Evidence
The bonds of the lipids in the cell membranes of Bacteria and Archaea are different.
The development and composition of flagellar are different.
What two groups are used to define interactions between and within species.
Interspecific - Between species e.g. Robin and an Ostrich
Intraspecific - Within species e.g. Scarlet Robin and the European Robin
Variation can be organised into two types. What are they? Provide examples for each.
Continuous - Individuals in a population that vary within a range,
Animals - Height / Weight / Cow Milk Yield
Plants - Surface area of leaves / Mass of seeds from a flower head
Microorganisms - Width / Length
Discontinuous - When there are two or more distinct categories.
Animals - Blood Group
Plants - Colour / Seed Shape
Microorganisms - Antibiotic resistance / Pigment production
What can factors can cause variation?
Genetic factors
Environmental factors
Both
Explain how genetic variation occurs.
Mutation - changes in the sequences of genes in DNA
Sexual reproduction - the creation of new combinations of genes. Independent assortment and crossing over.
An individual’s observable traits, such as height, eye colour, and blood type is called what?
Phenotype
What is an environmental factor?
Provide three examples of environmental factors.
Provide two examples of environmental variation.
Any factor that influences living organisms.
Climate
Diet
Culture and lifestyle
Accents
Pierced ears
Genetic and environmental factors can influence how some characteristics develop.
Provide two examples.
Height - Genes determine how tall an organism can grow, but diet and nutrient availability can affect this.
Flagellum - Genes determine if a microorganism can grow a flagellum, but some will only grow in certain environments.
What are adaptations?
Adaptions are changes to an organism that increase its chances of survival and reproduction.
How does calculating mean help when investigating variation?
It can show if there is variation between samples.
e.g. Height of a species of a tree in different woodlands.
Mean
Most samples include values on either side of the mean.
What sort of graph can you expect to see?
What do you call this?
Bell-shaped graph
Normal distribution
How do you calculate standard deviation?
What does the Spearman’s rank correlation coefficient show?
Whether the two variables are related, and if so, how strongly they are related.
Before investigating correlations, what should you come up with and what does it tell you?
Null hypothesis.
There is no correlation between the factors you are investigating.
Name, and give examples of three types of adaptations.
- *Behavioural**
- how an organism acts*
Possums play dead to increase their chance of survivial.
Scorpions dance before mating to attract a mate of the same species.
- *Physiological**
- processes inside an organism’s body*
Brown bears hibernate to lower their metabolism over winter to conserve energy.
Some bacteria produce antibiotics to kill other species of bacteria.
- *Anatomical**
- structural features of an organism’s body*
Otters have a streamlined shape. Easier to glide through water. Easier to catch prey and evade predators.
Whales have a thick layer of blubber. Keeps them warm in the sea. Increases chances of survival when food is scarce.
Give an example of convergent evolution.
Marsupial and placental moles.
Evolved on different continents.
Live in the same conditions (underground):
1 - Small/non-existent eyes
2 - No external ears to keep a streamlined head
3 - Claws, specialised in digging
4 - Tube shaped body and cone-shaped head which makes it easier to push through sand or soil
What was Darwin’s theory of evolution by natural selection?
(5 points)
Individuals within a population show variation in their phenotypes.
Predation, disease and competition create a struggle for survival.
Individuals with better adaptations are more likely to survive and pass on those adoptions.
Over time, the population with advantageous adaptations increases.
Over generations, favourable adaptations become more common in the population.
Give a brief summary of Darwin and Wallace’s interactions.
Darwin read a geology book about fossils being evidence of animals living millions of years ago.
Darwin used observations of finches to identify adaptations that correlated to different food sources on the various Galapagos Islands.
Alfred Wallace sent his own independent observations to Darwin for peer review and they presented a joint presentation.
What sources do scientists use to study the process of evolution?
Palaeontology - the study of fossils and fossil records
Comparative anatomy - the study of similarities and differences between organisms’ anatomy
Comparative biochemistry - similarities and differences between the chemical makeup of organisms
What are the implications of pesticide resistance for humans?
Crop infestations with pesticide-resistant insects are harder to control.
Farmers may have to use broader pesticides that kill beneficial insects.
A population of insects resistant to all pesticides could evolve.
New pesticides need to be produced which costs time and money.
What are the implications of drug resistance for humans?
Infections caused by drug-resistant microorganisms are harder to control.
It costs time and money to create new drugs.
List the unicellular kingdoms.
How do Fungi, Plantae and Animalia store food?
What are two differences between fungi and plantae?
Prokaryote, Protoctista, Fungi (can be multicellular)
Glycogen, Starch, Glycogen
Fungi - no chlorophyll, saprotrophic / Plantae - Autotropic
What are the advantages of phylogenic classification over the Linnaean system?
Shows evolutionary relationships that are not obvious when looking at characteristics.
A continuous tree so organisms do not have to be forced into groups.
It is clear where what the evolutionary position of a group is.
List three important facts about fossils.
The sequence in which fossils are found match their ecological links. e.g. plants existed before animals.
Similarities in the anatomy of fossil organisms can help identify ancestors
Fossil records are not complete because of soft body creatures decomposing, and earth movements destroying them.
What is a homologous structure?
One that appears superficially different but has the same underlying structure.
They provide evidence for divergent evolution. Where closely related species diversify and adapt to new habitats.
What is comparative biochemistry?
Similarities and differences in proteins and molecules.
e.g. Changes in base sequences of DNA or the order of amino acids.
What are 4 examples of anatomical adaptations?
Body covering - hair, scales, spines.
Camouflage
Teeth e.g. sheep have continually growing molars for munching.
Mimicry - copying the appearance of another organism to fool predators.
Give 3 examples of behavioural adaptations.
Survival - playing dead
Courtship - scorpions dancing, peacocks flashing
Seasonal - migration / hibernation
What two categories do behavioural adaptations fall into?
Innate behaviour - spiders build webs
Learned - otters using stones as hammers
Give three examples of physiological adaptations.
Poison production - plants protecting themselves / venom in reptiles
Antibiotic production (bacteria killing other bacteria)
Water holding - cacti / water-holding frog
All organisims are exposed to ______ ______ .
selection pressures
