Lectures(Midsem) Flashcards
(27 cards)
What is the first step in the origin of life?
Synthesis of small organic molecules, such as amino acids and nitrogenous bases.
What do small organic molecules form during the origin of life?
Polymers, such as proteins and nucleic acids.
What are protocells?
Droplets with membranes that maintained an internal chemistry different from that of their surroundings.
What is crucial for the process of inheritance in the origin of life?
The origin of self-replicating molecules.
What is evolution?
A process that describes how living things change over time through changes in their genetic material.
Why is evolution considered the core theme of biology?
It embodies both unity and diversity among living organisms.
What did Aristotle contribute to the understanding of life?
He wrote Scala of Natura (ladder of life) and proposed that all living things are arranged on a scale of increasing complexity.
According to Aristotle, what was his view on species?
Species are unchanging and perfectly adapted to their environment.
What is the theory proposed by Lamarck regarding evolution?
Organisms adapt to their environment and characters developed during their lifetime would be inherited by offspring.
What does the principle of ‘Use and Disuse’ state in Lamarck’s theory?
Organs strengthen with more use and deteriorate with infrequent use.
What criticism was made against Lamarck’s theory?
Rat tails regrow even after being cut off for 20 generations and Drosophila flies did not become blind after being bred in the dark for many generations.
What is Darwin’s theory of Natural Selection?
A fundamental mechanism of evolution where individuals with certain traits are more likely to survive and reproduce.
What are the two key factors in Darwin’s theory presented in ‘On the Origin of Species’?
Variation and natural selection.
What does natural selection lead to?
The accumulation of beneficial traits in the population.
What major event in Earth’s history is characterized by rapid speciation?
Cambrian explosion.
What is the first life-form on Earth?
Prokaryotes.
What distinguishes Eukaryotes from Prokaryotes?
Eukaryotes contain membrane-enclosed nucleus and other organelles.
What are protists?
A diverse collection of mostly unicellular eukaryotes that bridge unicellular and multicellular forms.
What does phylogeny study?
The evolutionary history of a group of organisms and their relationships.
What is a phylogenetic tree?
A visualization of ancestor-descendant relationships.
What approaches can be used to build a phylogenetic tree?
- Cladistic
- Phenetic
What is the cladistic approach based on?
An evolutionary approach to classification.
What are the three domains of life?
- Bacteria
- Archaea
- Eukarya
What is a characteristic of Bacteria in terms of peptidoglycan?
Present in their cell walls.
