Animals Flashcards
What are the five problems of life faced by all animal species?
Finding food, finding oxygen, maintaining water balance, removing nitrogenous waste and reproducing.
Name the principal nitrogenous waste product of each of the following animals:
freshwater fish
Seed-eating bird
Kangaroo
Fish - ammonia, water is abundant to dilute this toxic product
Bird - Uric acid, low toxicity and little water lost in excretion
Roo - urea, the need to conserve water makes it unavailable to dilute a toxic product such as ammonia, however it still needs more water for excretion than uric acid.
Relate the properties of the nitrogenous waste product to the environment of each animal:
freshwater fish
seed eating bird
kangaroo
Fish - ammonia is toxic that energetically cheap to produce and readily diluted by abundant water
Bird - uric acid has low toxicity and little water lost in excretion which helps conserve water on land. There is a significant energy cost
Roo - urea has low toxicity and is an intermediate energy cost which helps to conserve water on land
Explain the difference between radial and bilateral symmetry:
Radial symmetry: an animal or flower can be cut Longitudinally in any plane in the two halves will be the same
bilateral symmetry: there is only one position in which an animal or flower can be cut Longitudinally so that both halves will be the same
Why is the terrestrial environment described as the harshest of all environmental life?
The need for animals to have a high moisture content of cells and to have a moist surface across which oxygen uptake can occur makes the terrestrial environment more harsh than a marine or aquatic one.
In what ways is the cnidarians (jelly fish) body plan more complex than that of the poriferans (sponge)?
In contrast to poriferans, cnidarians have distinct tissues in their bodies.
What special problems are presented by parasitic lifestyle and how do parasitic flatworms and nematodes (roundworms) overcome them?
Reproduction and finding new host - reproduction may involve a motile stage that finds a new host and or an intermediate host that is eventually eaten by the final host
attachment to the lining of the host gut - special mouthpiece adaptations such as the scolex in tapeworms or piercing mouthparts of the nematodes
avoiding being digested by the host - a resistant cuticle
I cephalopod and a snail look very different but they are both classified in the phylum mollusca. what features are shared by cephalopods and other molluscs? what features are unique to cephalopods amongst the molluscs?
Common features: main body cavity a haemocoel (not a coelom)
Formation of a mantle from outgrowths from the dorsal surface
Radula (although cephalopods have beaks as well)
Trochophore larva that develops into a veliger larva
Differences: muscular foot is modified into a ring of tentacles in cephalopods
Cephalopods have a beak as well as a radula
Cephalopods have a closed circulatory system whereas Gastropoda and other molluscs have an open circulatory system
The Arthropods make up the great majority of animal species and in turn most of the arthropod species are insects. Suggest why there are so many insect species:
Diversity of habitats/food sources drives diversity of speciation and insects are able to utilise a wide array of habitats and a huge number of food sources. Flight makes almost every part of the terrestrial habitat available to insects and also enables them to exploit temporary resources,escape predators and disperse widely. The possibility of 2 life stages in the life history (egg and pupa) being resistant to environmental extremes such as heat and cold or drought also enables a wide range of habitats to be exploited.
