history of life Flashcards
(30 cards)
L.O: ORIGINS OF LIFE— explain how life began on Earth & identify key evolutionary milestones, including the RNA World hypothesis & major biological events
- Earth formed 4.6 billion years ago
- Early Earth (Primordial Soup); life began when Organic molecules formed in Earth’s early oceans, as demonstrated by the Miller-Urey experiment.
- RNA predated DNA & proteins as it was the first self-replicating molecule
The earliest life forms were prokaryotes, simple single-celled organisms without a nucleus.
L.O: DIVERSITY OF LIFE— define biodiversity, explore its levels & examine Canada’s unique ecosystems & the threats they face
- Biodiversity:
L.O: TAXONOMY- understand the hierarchical classification system & its role in organizing biodiversity & guiding conservation efforts
L.O: PHYLOGENETIC TREES— interpret phylogenetic trees to understand evolutionary relationships using data from genetics, morphology & fossils
when was Earth formed
4.6 billion years ago, through the assembly of an organic molecules
when was life likely originated
3.5 to 4 billion years ago in ancient oceans.
earth had key chemical ingredients that allowed life to start
methane
ammonia
water
hydrogen
abiogenesis
process of life arising from non-living matter like macromolecules
THE MILLER-UREY EXPERIMENT (1950S)
electric discharges
produced amino acids, nucleotides & other building blocks of life
DNA __________ proteins
proteins ________ ______
DNA encodes proteins
proteins catalyze DNA replication
how was RNA molecules formed?
early RNA molecules formed through the polymerization of ribonucleotides
WHAT’S THE RNA WORLD HYPOTHESIS
- RNA predated DNA and proteins as the first self-replicating molecule, kickstarting evolution
through natural selection - RNA molecules were crucial in the early stages of life because they could store genetic information and catalyze chemical reactions (acting as ribozymes).
THE EARLY EARTH (PRIMORDIAL SOUP)
a high-energy
environment rich in simple molecules.
methane, ammonia, water, and hydrogen played a role in making these organic compounds
KEY FEATURES OF RNA
- stores genetic information (sequence of bases: A,C,G, U)
- acts as a catalyst, forming new RNA molecules
- natural selection favoured RNA molecules with improved catalytic abilities
RNA to DNA to proteins (CHECK CHAT)
RNA speeding up, ribosomes catalyzing replication, formations of polypeptides chains of amino acids,
DNA key points
- DNA is more stable than RNA
making the primary genetic material - cell membranes (phospholipids) formed
compartments, enclosing RNA & proteins - these innovations paved the way for modern cells
CYANOBACTERIA EVOLVED ______ ABOUT ___billion years ago
photosynthesis, 2.5 billion years ago
CYANOBACTERIA’S OXYGEN PRODUCTION ….
transformed earth, enabling more complex life
When did the Cambrian explosion occur?
540 million years ago
plants and fungi colonized land about ….
500 million years ago
WHAT IS BIODIVERSITY?
- refers to the assortment of living things within an ecosystem, whether were looking at the whole planet or given area
BIODIVERSITY encompasses GENETIC DIVERSITY, SPECIES
DIVERSITY & ECOSYSTEM DIVERSITY
the evolutionary process shapes biodiversity
WHY DOES BIODIVERSITY MATTER?
ECOSYSTEM SERVICES— pollination, water purification, carbon
sequestration
biodiversity ENHANCES RESILIENCE TO ENVIRONMENTAL
CHANGES
CULTURAL & ECONOMIC BENEFITS— ecotourism, medicines, food
security
BIODIVERSITY UNDER THREAT what are the main threats and impact
- MAIN THREATS:
habitat
destruction
climate change
invasive species
pollution - IMPACT— Extinction reduces
genetic diversity and disrupts
ecosystems - were experiencing the 6th mass extinction
WHAT IS TAXONOMY?
the science of naming, describing &
classifying organisms
critical for identifying & protecting biodiversity; helps identify & protect
endangered species
