SBI3U

Dichotomous keys are used to identify species and their scientific names.

1. a. tail fins are horizontal—whale………………….go to 2 b. tail fins are vertical—fish……………………….go to 3 2. a. has teeth or tusk—toothed whale………………..go to 4 b. has no teeth………………………...BALEEN WHALE 3. a. has gill slits behind mouth—shark…….………...go to 5 b. has no gill slits……………………..NONSHARK FISH 4. a. black with white underside………….KILLER WHALE b. tusk, gray with dark spots………………....NARWHAL 5. a. head is hammershaped……..HAMMERHEAD SHARK b. tail is half the body length……….THRESHER SHARK

Bird W : Bird Y : Bird X: Bird Z:

 Species Diversity: the variety and abundance of species in a given area  Genetic Diversity: the variety of heritable characteristics in a population of interbreeding individuals.  Ecosystem Diversity: the variety of ecosystems in the biospheres.

Gene pool:  The different alleles available within a given population.  Represents the genetic diversity within a population Gene pool Alleles Diversity Population

 When a species is separated in two different regions, there is a lot of allelic variation between both regions.  This is due to the different environmental conditions that alter the genetic information. What happens to the genetic diversity of organisms when there is allopatric speciation?

1) Provide resistance to disease 2) Supports Conservation Biology What could be an advantage of genetic diversity?

Tasmanian Devil, native to southern state of Australia. When a population of species lacks genetic diveristy there is a greater chance that they will be affected by a certain disease. If the disease leads to death, with no genetic diversity, the species can become extinct. Thus genetic diversity enables organisms to survive environmental changes and promotes evolution

 Scientists’ knowledge of genetic diversity enables them to develop strategies to save endangered species. How could scientists help increase the genetic diversity within a population of species?  Scientists take species from a different location and introduce them into a new population. (controlled form of gene flow).  By introducing new species, new versions of alleles are introduced to the gene pool, thus increasing genetic diversity.

Biosphere Biotic Factor Abiotic Factor Ecosystem

 There are a variety of ecosystems found within the biosphere. Thus there is much diversity.  All ecosystems consists of a variety of biotic and abiotic factors that differ from system to system.  All biotic and abiotic factors help contribute and ensure the well functioning of the ecosystem.

Earth’s surface can vary physically and chemically depending on the region. This variation increases the biodiversity.

 The Ecosystems can provide many benefits to the organisms living within it.  All life on earth depends on the many goods that the ecosystem has to offer.  Ecosystem Service: the benefits provided by the ecosystem to humans.

 Each ecosystem provides a unique set of services that are essential to certain organisms.  Without this diversity, these services would not be available and thus would impact the survival of certain organisms.  Thus governmental and non-governmental agencies work together to ensure that these ecosystems are preserved and protected.

1) Climate regulation: the ability of an ecosystem to regulate CO 2, NO 2, CH 4 levels in the atmosphere. 2) Pollination: Ability to pollinate crops. 3) Wilderness: providing a habitat for wildlife 4) Food production: crops; livestock

 The greater the diversity of species within an ecosystem, the greater its ability to maintain equilibrium.  Resilience: ability of an ecosystem to remain functional and stable in the presence of disturbances.  The greater the diversity, the better the organisms within the system are able to adapt, thus maintaining the equilibirum.

 There are times when humans will enhance the services provided by the ecosystem by introducing their own benefits.  Although this may provide recreational advantages to humans, it can disrupt the entire ecosystem by interfering with the food chain.

 In California, scientists introduced a stock of non- native trout into the lake for recreational purposes.  Introducing the trout drastically reduced the number of amphibians and insects in the ecosystem. Why could this have occured?