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| Question | Answer |
| How do we explain the origins of life? | 1.Mythological/cultural 2.Religious 3.Scientific |
| Is evolution a fact or a theory? | Evolution is taught as a fact and a theory |
| What is the evidence in support of evolution as a fact? | Centres on four arguments 1.Micro evolution 2.Macro evolution 3.Imperfections 4.Molecular evidence |
| Explain the concept of micro evolution | it involves small changes in species e.g evolution of resistance to pesticides, viruses and antibiotics. Another example can be artificial selection |
| Explain the concept of Macro evolution | involves large changes over a long period of time, they present patterns to infer processes in the past( e.g vertebrate embryos) |
| What is the definition of Evolution? | the change in genetic composition of a population from generation to generation |
| What is the definition of Natural Selection? | a process whereby individuals with certain heritable traits survive and reproduce at higher rates than others |
| What are the Results of selection? | Adaptation: Any trait/character/feature that enhances the chance of survival and/or reproduction |
| What is selected? | 1.Phenotype: all observable attributes 2.Genotype: from which phenotypes arise |
| What are the types of selection? | 1.Natural selection--> survival and reproduction 2.Sexual selection--> mating oppurtunity |
| Name the three modes of selection | 1.Stabilising selection--> maintain average 2.Directional selection--> select one direction 3.Disruptive selection--> select two extremes |
| How does Sexual selection differ from Natural Selection? | Natural selection is survival of the fittest, while sexual selection is a preference for a given trait made by the limiting sex |
| What is a species? | A group of distinct organisms capable of interbreeding but reproductively isolated from other species |
| Explain how interbreeding is prevented | Prevented by two isolating mechanisms 1.Pre-zygotic Mechanism 2.Post zygotic Mechanism |
| What is the role of the Pre-zygotic isolating Mechanism? and give examples | To prevent fertilisation from taking place e.g 1. Temporal- day, season 2. Ecological- habitats 3. Behavioural- courtship 4. Gametic- egg and sperm incompatible |
| What is the role of the Post- zygotic isolating Mechanism? and give examples | Ensures reproductie failure e.g 1. Hybrid non viability: prohibit normal embryonic development 2. Hybrid Sterility:hybrids genetically incompatible |
| How do new species arise? | 1.Allopatric speciation 2.Sympatric speciation |
| Define Allopatric Speciation | speciation that occurs when biological populations of the same species become isolated from each other to an extent that prevents or interferes with genetic interchange |
| Define Sympatric Speciation | the process which new species evolve from a single ancestral species while inhabiting the same geographic region |
| How does a new form arise? | 1. Allometric Growth- differences in relative growth rates of body parts 2. Homeosis- alteration in spatial arrangement of body parts |
| Define Phylogeny | Evolutionary history of a species or group of species |
| What is systematics? And what is it used for? | Analytical approach to understanding the diversity and relationships of organisms(both extant and extinct) |
| Define Biogeography | geographic factors that correlate with spatial distribution of life |
| What is mass extinction? | the extinction of a large number of species within a relatively short period of geological time |
| What are the four constraints animals had to overcome to adapt to a terrestrial existence? | 1.Breath air 2.Prevent dehydration 3.Reproduce on land 4.Locomotion |
| Define sub-species | distinct morphologically and genetically but similar enough so that they can potentially interbreed |
| Define the term animal | “ any living organism characterized by voluntary movement, the possession of specialized sense organs enabling rapid response to stimuli, and the ingestion of complex organic substances” |
| What are homeotic genes? | regulatory genes controlling body plans of plants, animals, fungi |
| What is symmetry? | Correspondence in size or shape of parts on opposite sides of a median plane. |
| What happens in radial symmetry? | can be divided into similar halves through more than 2 planes through the longitudinal axis |
| What effect can radial symmetry have on an animal? | This type of symmetry well equips the animal for meeting the environment from any particular side |
| What happens in bilateral symmetry? | can be divided into similar halves along a sagittal plane into mirrored halves (right and left) |
| Define Cephalization | a distinct advantage for an animal that moves a lot in any one particular direction |
| Define Diploblastic | two germ layers ( no mesoderm) |
| Define Triploblastic | three germ layers |
| Define Phyla | a major taxonomic division of living organisms that contain one or more classes. An example is the phylum Arthropoda (insects, crustaceans, arachnids, etc., and myriapods) |
| What are some of the characteristics of Phylum Poriferia? | • Simplest multicellular animals • No organs or true tissues ( no nervous system) • Sessile ( don’t migrate, just sit there) • Body with pores • Gelatinous matrix stiffened with minute spicules • All aquatic |
| What are some of the characteristics of Phylum Cnidaria? | 1.radial symmetry 2.Gastrovascular cavity with one opening 3.Most have two forms- polyp and medusa 4.Carnivores- prey captured using namtocysts |
| Can nematocysts affect humans? | Yes, Some nematocysts can penetrate human skin resulting in sensations ranging from minor irritation to great pain and even death, depending upon species |
| Define the term Blastula | An early embryonic form produced by cleavage of a fertilized ovum and consisting of a spherical layer of cells surrounding a fluid-filled cavity. Also called blastosphere. |
| Define the term Blastopore | A blastopore is an opening into the archenteron during the embryonic stages of an organism |
| Define the term Archenteron | the cavity within an embryo at the gastrula stage of development that eventually becomes the digestive cavity |
| What are the types of sexual selection? | 1.Intrasexual(male/male competition) traits which facilitate competition with sex(e.g body size) 2.Intersexual(female choice) traits which facilitate one sex to attract other sex(e.g ornaments or bright colours) |
| Does natural selection produce perfect organisms? | Does not produce perfection but constrained by past Terrestrial vertebrates: vertebral column and four limbs Difficulty of childbirth and lower back pain |
| What does phylogenetic systematics do? | connects classification with evolutionary history 1.Hierachial classification 2.Linking classification with phylogeny |
| What is cladistics? | shared primitive and shared derived characteristics |
| What are the three main flat-worm classes? | 1.Fee-living flatworms (Turbellaria) 2.Tapeworms- all parasitic (Cestoda) 3.Flukes- most parasitic (Trematoda) |
| What are some of the characteristics of Phylum Platyhelminthes(flatworm)? | 1.About 20,000 species 2.Triploblastic(acoelomate) 3.Bilateral Symmetry(moderate cephalization) 4.Organ-system level of organization 5.Body flattened dorsoventrally 6.Gastrovascular cavity-one 7.opening(“mouth”) |
| What are some of the characteristics of Phylum Nematoda(roundworms)? | 1.Triploblastic, bilateral 2.Complete digestive tract 3.Pseudocoelom fluid serves as a blood vascular system 4.Longitudinal muscles only |
| Define Coelom | the cavity within the body of some animals formed by the splitting of the embryonic mesoderm into two layers. In mammals it forms the peritoneal, pleural, and pericardial cavities |
| What is a true coelom? | fluid filled cavity derived from the mesoderm |
| What are some of the differences between protostomes and deuterostomes? | 1. Patterns of cleavage- Protosomes- spiral and determinate Deuterostomes- Radial and indeterminate 2. Coelom formation- Protosomes- Schizocoelous- mesoderm splits to form coelom Deuterostomes- Enterocoelous- pockets of archenteron form coelom |
| What are some of the characteristics of Phylum Annelida? | 1.Metamersim(segmentation) 2.Coelom well developed 3.Closed circulatory system 4.Complete digestive and nervous system |
| What are some of the characteristics of Phylum Arthropoda? | 1.Segmentation 2.Jointed limbs 3.Hard exoskeleton 4.Open circulatory system |
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