Class Notes (809,022)
Canada (493,491)
Biology (6,677)

Biodiversity Notes

3 Pages
Unlock Document

Western University
Biology 3484A/B
Nina Zitani

Biodiversity – Oct. 8/12 - Eukaryote phylogeny: The cladogram shows that animals and fungi are more closely related to one another than they are to any other major clade. Animals (metazoa) are a branch of the opisthokonts, which are part of the unikonts. Opisthokonta branch into many things. Choanoflagellates are unicellular, microscopic, heterotrophic, abundant, and ubiquitous in all aquatic environments. They are under-studied. They are the closest living relatives of animals. Further study should lead to insights into the earliest events of animal evolution. They are an important component of marine plankton and the food chain. - What is an animal?: Eukaryotic cells lack cell walls. Animals have multicellular tissues and organs, though some are microscopic. Molecular data supports monophyly and so does the extra-cellular matrix (ECM). The ECM is composed of collagen and other molecules. Molecules are created inside cells, but the ECM exists outside cells. The ECM fills up the spaces between cells and serves as a structural element. It is flexible and can be squished and return to its original shape. ECM plays a key role in growth and development of the individual. ECM is a component part of bones, shells, and other structures. Adult animals are diploid organisms and they produce haploid gametes. They undergo sexual reproduction, which involves fertilization and formation of a zygote and a multi- cellular embryo. Some animals undergo asexual reproduction (ex. some insects). Animals are heterotrophic and can be filter-feeders, scavengers, carnivores, herbivores, parasites, and parasitoids. They ingest food and digest it internally. Most animals are capable of complex, rapid movement, and this is important for the pursuit of food and escape from predators. The ecological role of animals is they are primary consumers of biomass on earth and they are a food source for other organisms. - Invertebrate is not a monophyletic group. It is a word to describe animals without backbones or lacking a vertebral column (ex. annelids, molluscs, arthropods). Vertebrate (vertebrata) is a monophyletic group and it includes animals with a skull and backbone, or vertebral column. These are historical terms and are no longer a valid dichotomy. - Animalia (metazoa) evolution – major events: Eukaryotic cells were present 2BYA (Proterozoic). There are animal fossils dating to 630MYA and these are relatives of today’s jellyfish and sea anemone. Green algae and probably fungi were present in oceans (late Proterozoic). The Cambrian period (began 550MYA). The Cambrian explosion was a relatively rapid appearance of most major phyla (fossil record) in oceans (early Paleozoic). The Cambrian explosion was fast in the sense of the geologic time scale, over several millions of years. The Ordovician period (began 480MYA) was a time of animal diversification, with vertebrates in oceans and invertebrate animals (ex. arthropods) colonizing land (along with plants and fungi). The fossil record for invertebrates is not as good as vertebrates because of their physical structures. During the Silurian period (began 440MYA), on land invertebrate animals diversified (along with plants and fungi). During the Devonian period (began 420MYA), there was continued diversification on land. Fins evolved into 4 limbs. Amphibians are the first land vertebrates, but they were dependent on water for reproduction. The carboniferous period (began 360MYA) saw the development of the amniotic egg, amniota, and land vertebrates totally adapted to life on dry land. The Permian period began 300MYA. The end-permian mass extinction resulted in 95% of life going extinct. It was mostly marine invertebrates and insects, and species and higher taxa, but not phyla (ex. arthropoda). The Mesozoic era (began 250MYA) saw animal diversification in oceans and on land. There was also coevolution with angiosperms (flowering plants). - Symmetry in animals: The body plans of most multicellular animals exhibit some form of approximate symmetry (not perfect symmetry). A small minority are asymmetric. Radial symmetry (basal) is when the or
More Less

Related notes for Biology 3484A/B

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.