BY2.1 Flashcards
(27 cards)
Where does the highest and lowest biodiversity exist?
Highest = equator (rainforest=terrestrial, coral reefs=aquatic)
Lowest = poles
What is the mechanism that new species arise from?
Natural selection from a common ancestor
Name the animal used to show natural selection from a common ancestor
Finches from South America to the Galápagos Islands
Describe the process of natural selection
- within the common ancestor species genetic variation exists due to mutation
- there is an overproduction of offspring within a population e.g. Common ancestor finches arrive on the one island and interbreed
- however the population level remains constant due to a high mortality rate
- the overproduction if offspring leads to increased competition, therefore only certain individuals will have beneficial characteristics with give them a selective advantage to the main selection pressure
- these are more likely to survive and reproduce, therefore their offspring are more likely to inherit the beneficial characteristic
- if this process continues from generation to generation the beneficial characteristic frequency will increase in the population
Name the 2 main ways organisms are classified (classification systems) and describe each
Taxonomic system - uses the principle of hierarchy. Take a large group of organisms and divide them into smaller groups, and each member of each group shares common features/characteristics/traits e.g genes/proteins/morphology. There can be no overlap i.e. 1 organism can be placed into 1 group
Phylogenetic system - the system allows us to see the points of divergence from the common ancestor group, and it allows us to see how closely related groups are because of their points of divergence.
\_\_\_\_\_ amphibians
Fish\_\_\_\_\_/
/
/
Common ancestor
Name the different stages of the taxonomic model and the way to remember it
Kids Play Carelessly Over Farmer Giles Styles
Kingdom (Anamalia) Phylum (Chordata) Class (Mammalia) Order (Primates) Family (Hominidae) Genus (Homo) Species (sapiens)
How do we name organisms?
Binomial system
Uses the Genus and Species Taxa
E.g. Homo sapiens = humans
This system avoids confusion of dealing with local names and different languages
What are the 2 main sources of evidence to support evolution
Fossil record morphology and Biochemical Analysis
We can only use certain fossil record morphology data to support evolution if they have….?
Homologous structures
Example of a homologous structure
Pentadactyl limb
E.g. Seal flipper = swimming
Bird wing = flying
What is a pentadactyl limb
Same structure, different functions
This is an example of divergent evolution from a common ancestor
What is an analogous structure
Different structure, same function
E.g. Bird wing and insect wing
Example of convergent evolution and CANNOT be used as evidence of evolution from a common ancestor
Describe biochemical analysis
Involves comparing the DNA base sequence (DNA fingerprinting), or amino acid sequence (in a protein) the more similar the sequence (DNA base/ Amino acid) the more closely related the species are
Most accurate way of determining relatedness
Which 3 phyla Taxa must we be familiar with
Chordata, Arthropoda, Annelida
What is the gas exchange surface, habitat and body covering of fish
Gills
Water
Scales
What is the gas exchange surface, habitat, body covering of amphibians
Soft moist skin and simple lungs
Land but need water for life cycle
Soft moist skin
What is the gas exchange surface, habitat, body covering and gestation of reptiles
Simple lungs
Land
Dry scaly skin
Lay eggs with leathery shells
What is the gas exchange surface, body covering, gestation and other characteristics of birds
Lungs
Feathers
Eggs with hard shells
Forelimbs modified for flight, endothermic
What is the gas exchange surface, body covering, gestation and other characteristics of mammals
Lungs
Hair
Internal gestation
Endothermic, double circulation, mammary glands, sweat glands
What are the 5 classes of the phylum Chordata
Amphibians, reptiles, birds, mammals, fish
What is the one class of arthopoda we need to know
Insects
What are the 2 important characteristics of Arthropoda and why are they important
Jointed legs - modified to perform a variety of functions, including walking, swimming, jumping, feeding and reproduction
Exoskeleton - the outermost layer of cells of the body secretes a thick wax cuticle, which consists mainly of chitin. This performs several functions
• in the most terrestrial Arthropods the exoskeleton is covered with a layer of wax (chitin) which reduces water loss
• protection of internal organs and from predators
• provides a point of attachment for muscles
What is the main disadvantage of the arthropods exoskeleton
It’s fixed in size and doesn’t grow with the animal. In order to grow an arthropod must periodically shed its exoskeleton (ecdysis). This leaves the animal especially vulnerable as the new exoskeleton hardens
What is the body structure, circulatory system, nervous system, gas exchange surface and locomotion of Annelida
- Segmented body, divided internally by partitions (septa)
- Closed circulatory system containing oxygen carrying pigment e.g. Haemoglobin
- nervous system with a primitive brain
- thin, permeable, moist skin
- hydrostatic skeleton
