Darwin and Diversity 2 Flashcards
What is biodiversity?
A measure of the variety of life at all levels.
What is biodiversity?
A measure of the variety of life at all levels.
What are the three levels of biodiversity?
Ecosystems, species, genes
What is the order of hierarchal classification?
Kingdoms, Phylums, Class, Order, Family, Genus, Species
What are described species?
Species which have been named and have a published description.
What are undescribed species?
Species which have not been scientifically recognised but are informally recognised as a distinct species.
Approximately how many described species are there?
1 - 2 million
Approximately how many described eukaryotic species are there?
~1.8 million
What is the most recent estimate of the number of eukaryotic species, including undescribed species?
8.7 ± 1.3 million
What does a species scape do?
Ranks groups of organisms according to their relative contribution to biodiversity.
How much of the worlds animal biodiversity do birds and mammals make up?
~2%
How much of the worlds animal biodiversity do insects make up?
~75%
What are biodiversity hotspots?
Areas which contain unusually large amounts of biodiversity.
How much landmass do all biodiversity hotspots take up?
Where are the biodiversity hotspots?
Usually around the tropics, but also in places like Madagascar and New Zealand.
Why are most biodiversity hotspots around the tropics?
- There is more land of organisms to live on.
- No glaciation occurred so environmental conditions have not been drastically altered
- More energy from sunlight reaches the tropics, enabling more plants to live here
Why are most biodiversity hotspots around the tropics?
- There is more land of organisms to live on.
- No glaciation occurred so environmental conditions have not been drastically altered
- More energy from sunlight reaches the tropics, enabling more plants to live here
What are the three levels of biodiversity?
Ecosystems, species, genes
What is the order of hierarchal classification?
Kingdoms, Phylums, Class, Order, Family, Genus, Species
What are described species?
Species which have been named and have a published description.
What are undescribed species?
Species which have not been scientifically recognised but are informally recognised as a distinct species.
What is an animal? (3)
- multicellular
- heterotrophic
- eukaryotic
Approximately how many described eukaryotic species are there?
~1.8 million
What is the most recent estimate of the number of eukaryotic species, including undescribed species?
8.7 ± 1.3 million
What does a species scape do?
Ranks groups of organisms according to their relative contribution to biodiversity.
How much of the worlds animal biodiversity do birds and mammals make up?
~2%
How much of the worlds animal biodiversity do insects make up?
~75%
What are biodiversity hotspots?
Areas which contain unusually large amounts of biodiversity.
How much landmass do all biodiversity hotspots take up?
Where are the biodiversity hotspots?
Usually around the tropics, but also in places like Madagascar and New Zealand.
How much biodiversity do biodiversity hotspots contain?
Around a third of all plants, amphibians, birds, reptiles, and mammals.
Why are most biodiversity hotspots around the tropics?
- There is more land of organisms to live on.
- No glaciation occurred so environmental conditions have not been drastically altered
- More energy from sunlight reaches the tropics, enabling more plants to live here
What is the relationship between body size and diversity?
Biodiversity is inversely proportional to size.
There is less diversity among very large animals, as they require a lot of energy and tend to overheat.
It seems that there are also very few organisms
How many organisms
up to 100 million
What is the Shannon Diversity index (H) used for?
To measure the biodiversity in an area.
What is the Shannon Diversity Index?
∑(p_n ln(p_n)) when p_a, p_b. . . are the different species in an area
What does a large value on the Shannon diversity Index mean?
Large amounts of biodiversity
What is an animal? (3)
- multicellular
- heterotrophic
- eukaryotic
What type of tissues do animals have?
Tissues which develop from embryonic layers
Which two characteristics are conserved among animals?
- production of collagen
* possession of Hox genes, especially the Homeobox sequence
What is symmetry?
A correspondence in the size and shape of body parts on opposite sides of a median plane.
What is radial symmetry?
Symmetry through two or more planes through the longitudinal axis.
What is the body structure of radially symmetrical organisms?
They have an oral (mouth) and aboral (no mouth) end.
What is the advantage of radial symmetry?
It enables organisms to meet the environment equally well from all directions, so is highly beneficial to stationary organisms.
What is bilateral symmetry?
Symmetry along the bilateral plane.
What is the body structure of bilaterally symmetrical organisms?
They have a right and a left side.
What is cephalisation?
The concentration of the sensory structures at the head end of the organism.
Who is cephalisation beneficial for?
Organisms which move a lot in one particular direction, such as predators and fleeing prey.
What type of organisms are cephalisation found in?
Bilaterally symmetrical organisms.
What is gastrulation?
The infolding of the blastula to for the archenteron and germ layers.
What is the archenteron?
An deep, narrow, blind-ended tube which develops into the digestive tract.
What is the blastopore?
The opening of the archenteron.
What are the three germ layers?
endoderm, ectoderm, mesoderm
What does the endoderm develop into?
gut, liver, and lungs
What does the ectoderm develop into?
skin
What does the mesoderm develop into?
muscles and other organs
Which germ layers do diploblastic embryos have?
endoderm and ectoderm
How do diploblastic animals move?
Diploblastic embryos don’t have a mesoderm, so the developed animal does not have muscles. They move by contractile elements in their skin.
What is the oldest phylum?
Porifera (sponges)