2.1 Evolutionary History of Organisms Flashcards
What is biodiversity?
A measure of the number of species on the planet.
What is a species?
A group of organisms that can interbreed under natural conditions and produce fertile offspring.
How does the number of species per square kilometer change as one moves from the poles to the tropics?
It increases
Where are the most diverse habitats on the planet?
Tropical rain forests and coral reefs.
What do the fossil records tell us about life on earth?
Most species are now extinct.
How has biodiversity changed during the past?
Mass extinctions cause ‘bottlenecks’ in biodiversity, where there are not many species on the planet.
These are followed by radiations of new species.
Where are the least diverse habitats on the planet?
The bottom of the ocean and polar regions.
What process drives the evolution of new species?
Natural selection (Darwin)
Give an example of adaptive radiation.
Darwin’s Galapagos finches.
Each island has a unique climate and food source.
The birds on different islands had different mutations causing variations in beak size and shape.
Some beaks were better suited to survival on that specific island.
Those finches with the mutated gene would survive longer. They would breed and pass on the beneficial gene to their offspring.
What is the classification of organisms based on?
Their evolutionary relationships.
What is the simple phylogenetic tree?
A classification concept
What is the heirarchical system of classification?
Kingdom, phylum, class, order, family, genus, species
What are the 5 kingdoms?
Animalia, Plantae, Fungi, Prokaryota, Protoctista
What are the main characteristics of the Animalia kingdom?
Nervous coordination
Cells lacking cell walls
Multicellular
Heterotrophic nutrition (they eat)
What are the main characteristics of the Plantae kingdom?
Cellulose cell walls
Chloroplast for photosynthesis / autotrophic (make their own food)
multicellular
