OS109 - Biodiversity Flashcards
(24 cards)
What is the species-area relationship?
As size of geographical area increases, so does the number of species it contains
This principle illustrates how larger areas tend to support more species due to increased habitat diversity.
What major factor determines species loss?
Habitat loss and fragmentation
An example includes infrastructure like roads that disrupt habitats.
How many animal phyla occur in the sea compared to terrestrial environments?
All 34 animal phyla occur in the sea, while only 14 of these occur on land
This indicates greater diversity in marine environments.
What percentage of marine phyla live in/on the sea floor?
98%
This includes benthic organisms, with only 2% floating or actively transporting.
How do food chains differ between ocean and land?
Food chains in the ocean average 5 links, while those on land average 3 links
This reflects the complexity of marine ecosystems compared to terrestrial ones.
What challenge do open oceans present in biodiversity conservation?
They make sectioning biogeographic regions difficult
This complicates conservation planning and management.
What is an endemic species?
A species that occurs in one area and nowhere else
Endemic species are crucial for understanding biodiversity and conservation.
What percentage of named Species are Marine?
15%
What is the significance of the ‘Garden’ of Ediacara?
- Earliest animals with strange leaf-like shapes, soft bodies, mostly without mouths or guts.
- No light on Edicarian sea floor
- Contain symbiotic algae/bacteria and uses Chemosynthesis
They contain symbiotic algae/bacteria and use chemosynthesis.
What major event is referred to as the Cambrian Explosion?
A sudden appearance of all major animal groups around 550 million years ago.
This includes the first animals with hard parts.
What is Chordate Pikaia?
The first organism that belongs to the vertebrate phylum.
It is a chordate.
What are the theories for current Biodiversity resulting after Cambrian explosion?
Factors include:
* Continental drift from huge supercontinent creating shallow waters and new habitats
* Warmer climate with lower oxygen content
* Developmental genetics related to Hox gene mutations.
What marks the start of the Cambrian Period?
Huge radiation and appearance of major groups including jawless fish and marine plants.
It ends with stabilization of many new groups but little ecological specialization.
What significant event occurred during the Ordovician Period?
The appearance of jawed fish and a stable biodiversity for a quarter billion years.
Blood viscosity was 1/3 that of seawater from evolving in freshwater.
What characterized the Devonian Period?
Known as the Age of Fish, featuring the first amphibians and earliest insects.
What was significant about the Permian Period?
The appearance of mammal-like reptiles and an extinction event that marked the end of many species including trilobites.
What does the Mesozoic Period encompass?
Includes the Triassic to Cretaceous Periods, marked by the rebirth of marine biodiversity and the emergence of dinosaurs.
What happened during the Cretaceous Period?
Extinction of ichthyosaurs, plesiosaurs, mesosaurs, ammonites, dinosaurs, and flying reptiles.
This period ended with the largest biodiversity crash known.
What is the significance of the Cenozoic Period?
Marks the beginning of the Age of Mammals and flowering plants, leading into the Age of Insects, Molluscs, Fish, and Homo.
What defines the Anthropocene epoch?
An age of human influence and unprecedented biodiversity decline.
What percentage of all species that have ever existed are extinct?
99%.
What do background extinction rates account for?
Regular extinctions due to natural cycles, accounting for 96% of all extinctions over the past 600 million years.
What is the average lifespan of species in the fossil record?
5-10 million years.
What is the current event referred to as the Sixth Extinction Event?
An ongoing extinction event that we are currently experiencing.
