Intro pt1 (Meg- finished) Flashcards
What is macroscopic nudibranch?
example of group of marine mollusks renowned for their unusual shapes + bright coloration
Name some adaptation of macroscopic nudibranches and how can these be explained?
Many contain toxins for defence against predators
Colouration may also be an adaptation to deter potential predators
Scientific explanation = THEORY OF EVOLUTION BY NATURAL SELECTION
What is the key feature of HIV looked at by evolutionary biologists?
= rapid evolution that can be random variation but also natural selection taking place to help evade immune systems
What are the 2 forms of HIV in humans and where did they come from?
HIV-1 arose from SIV that infected chimpanzees
HIV-2 arose from SIV that infected sooty mangabev (monkey)
What is this graph showing?
Finland- 1978-1993:
- Increase in the use of penicillin-like antibiotic (blue line)
- Matched by dramatic increase in % of antibiotic-resistant isolates of bacteria
Similar patterns have been seen with HIV resistance to AZT = nowadays multiple drugs involved in order to prevent resistance
How does malaria effect the human genome?
+ 2 examples
Protective polymorphisms to protect against malaria:
- Sickle-cell trait = having this phenotype (only one copy of sickle cell trait) can protect against malaria
- Blood group variant Dantu provides 74% protection against all forms of severe malaria in homozygous individuals
How does Dantu effect the ability of merzoite malaria to invade red blood cells?
- Strong link between RBC tension and merozoite invasion- tension threshold identified where invasion rarely occurs- Dantu RBCs have higher average tension than non-Dantus RBCs = greater proportion resist invasion
What is evolution concerned with?
explaining + understanding the diversity of living things
- History behind diversity? + causes?
What is used to study evolution?
- DNA sequences
- Proteins
- Biochemical pathways
- Embryological development
- Anatomical features
- Behaviours
- Life histories
- Interactions
- Fossils
Name + define the 2 ways of explaining why something happens?
Proximate causes = concerned with physiology of an animal causing an event / behaviour
Ultimate causes = evolutionary cause of an event or behaviour
What are the proximate and ultimate causes of the Marsh vs Grasshopper Warbler sonograms?
Marsh have more complex songs compared with the Grasshopper
Proximate = brain structure of Marsh produces more complex songs
Ultimate = natural selection- females prefer more complex songs = more reproductive success of males with more complex songs
Is evolution a fact or a theory?
Considered to be both- Stephen Jay Gould
Why is evolution considered a fact?
overwhelmingly validated by evidence- based on repeated experimental observations- no debate evolution is a fact
Define: theory
a well-substantiated explanation of some aspect of the natural world that can incorporate facts, laws, inferences, and tested hypotheses
How are theories formed?
from hypotheses repeatedly tested to disprove of falsify them
What is the theory of evolution?
Network of theories that created biology
In Darwins original formulation, what 5 theories were proposed as part of his theory of evolution?
- Populations changing over generations
- Gradual Change
- Speciation
- Natural selection
- Common descent
Define: hypothesis
A proposed explanation for a phenomenon made as a starting point for further investigation
Define: law
A statement based on repeated experimental observations that describes some phenomenon of nature- proof what and how something happens but not why
Name the stages of evolution discovery
- Farmers tale
- Greek Philosophers
- Aristotle
- Al-Jahiz
- Linnaeus
- Lamarck
- Alfred Wallace
- Darwin
- Gregor Mendel
- Modern synthesis
Outline the farmers tale
Neolithic revolution - involved the domestication of crops + animals
Outline the greek philsophers contribution to evolution
Anaximander = nature ruled by laws (like human societies) and anything that disturbs the balance of nature does not last long
- Empedocles rudimentary (= underdeveloped / limited to basic principles) theory of evolution:
1. Life 1st emerged as a bunch of disassociated body parts (crawling arms, walking legs etc)
2. As time went on these parts came together and attached = creatures with random configurations
3. Some creatures had 10 arms, 30 eyes + butts for heads etc- but those more suited for survival had more sensible combinations like 2 arms, 2 legs etc and outcompeted others - Xenophanes- examined fossils and suggested that water must have covered all of earth’s surface = correct
Ouline Aristotle’s contribution to evolution
= Grandfather of taxonomy- began hypothesis testing as believed logical principles cannot be accepted unless tested:
1st to use comparative anatomy approach + aware of certain correlations in anatomy- morphology
He classified all living organisms hierarchically and based on observation = Great chain of being (1st gradation in nature) - fits with the belief that earth was only about 6000 years old:
- Plants at the bottom and humans at the top- representing a progression from the most imperfect to the most perfect
- Each species is formed individually with its own purpose and place in nature- no species evolves into a new species
= This view was firmly established for the next 2000 years- God creating an infinite and continuous series of life forms that remain unchanged and were created in their present life form
Outline Al-Jahiz contribution to evolution
“Book of living being”
- Took divine creation of species for granted but understood interconnectedness of organisms (food chains) as well as survival of fittest
Ouline Linnaeus’ contribution to evolution
= Father of taxonomy
believed he was revealing the unchanging order of life created by God- Binomial nomenclature (species + genus):
= system of scientifically naming organisms which made a major contribution and gave rise to later evolutionary theories
Named + classified many species but this doesn’t have anything to do with evolution BUT important because he broke convention of Aristotle that life is a continuous chain of being, instead believed in discrete separate species
Describe Lamarcks theory
Proposed theory of species change based on 2 ideas:
1. Increased complexity + gradual changes along same phyletic line
2. Slow process driven by environment
He believed that microscopic organisms appear spontaneously from inanimate materials, then evolve gradually + progressively into more complex forms- striving for perfection with ultimate goal = humans
Where was Lamarcks theory wrong?
Also believed that evolution was mostly due to inheritance of acquired characteristics (where his theory was wrong) as creatures adapted to their environments
Compare Darwin’s and Lamarcks hypotheses
Lamarck’s hypothesis:
- Life has originated many times- red dots
- Each lineage that descends from one of the origins (red dots) becomes more complex
- Organisms range from recently originated, simple forms to older more complicated
Darwin’s hypothesis- represented by phylogenetic tree:
- Single ancestor (red dot)- different lineages arise by speciating (splitting) from existing lineages
- Some may undergo less modification from ancestor than others
- Darwin suggested species become more different from each other in various features- not necessarily more complex
What is the main contrast between Lamarck and Darwin?
Lamarck- traits change within lifetime of individuals based in their needs- these acquired chnages are passed onto next gen e.g. giraffes develop longer necks to reach higher leaves
Darwin- Variation among individuals at start of gen- individuals with certain favourable traits have a greater chance of survival
Variation is inherited, so survivors pass on their traits to the next gen
