Biodiversity, Classification, Natural Selection And Evolution. Flashcards
What powers the ecosystems on the earth?
Energy from the sun which is used by plants in photosynthesis to create chemical energy e.g glucose.
Define Biodiversity.
A measure of the number of different species in an area or on the planet as a whole.
What is plant biomass controlled by?
The variables controlling the rate of photosynthesis:
Light intensity
Temperature
availability of liquid water.
Where is the highest plant biomass found and why?
Light intensity, temperature, and the availability of liquid water change with latitude and is maximum at the equator where plant biomass is at its maximum. Biomass is therefore minimum at the poles as latitude increases.
What other factors affect biodiversity?
Changes in climate e.g glaciations.
Catastrophic events e.g a meteor strike on earth.
What is natural selection?
The selection by nature of individuals with features best suited to survive to reproduction in a particular habitat.
What is a selective agent?
Anything in the natural world which has an impact on survival rate or reproduction.
Give some examples of selective agents.
Competition for food, space etc Infectious disease Predators Parasites Bioaccumulation
How is Natural selection made possible?
Because individuals in a population are genetically individual from one another due to sexual reproduction.
How do species adapt to change (the addition of new selective agents)?
By becoming better fitted to its particular habitat.
What is adaptive radiation?
The rapid development of many new species from one ancestral type due to extinction of competitors or the creation of new land.
Describe the adaptive radiation seen on the Galapagos island.
The creation of thirteen different finch species from the original one. (Darwin’s finches) this was possible due to geographical isolation.
What is the science of classification called?
Taxonomy.
What are the three ideas taxonomy is bassed on?
- ) species have evolved over time.
- ) the more features two species share the more closely related they are.
- ) the more closely related they are, the shorter time ago they shared a common ancestor.
What can be said about the lineage of the species alive on earth today?
We are descendants pre-existing forms of life, many of which are now extinct.
What is conversant evolution?
This means that some features such as Wings have evolved to look similar because they have the same function I.e flight.
What is the name given to the similar structures created through convergent evolution?
They are analogous structures.
Why must analogous features be ignored in taxonomy?
Because we are looking for homologous features I.e same origin, different functions.
What is a penta-dactyl limb plan?
This is an arrangement of bones found in the arms of all vertebrates. This consists of one bone(upper arm) joined to two bones (lower arm) joined to five bones(digits). This arrangment has been modified by natural selection for perform a range of functions in fish, amphibians, reptiles, birds and mammals.
How has relatedness been determined traditionally?
Morphology (external structures) Anatomy (internal structures) Embryology (development of the embryo) Fossil records (the use of fossils to deduce ancestry.