2.1 Species and Populations ESS1 2015

SIGNIFICANT IDEAS: ▪ A species interacts with its abiotic and biotic environment, and its niche is describe by these interactions. ▪ Populations change and respond to interactions with the environment. ▪ All systems have a carrying capacity for a given species.

APPLICATION & SKILLS ▪ Interpret graphical representations or models of factors that affect an organism’s niche. Examples include predator-prey relationships, competition, and organisms abundance over time. ▪ Explain population growth curves in terms of numbers and rates.

KNOWLEDGE & UNDERSTANDING ▪ Define and Give Examples of the terms: species, habitat, niche, abiotic factors, biotic factors, population, limiting factors, carrying capacity ▪ Distinguish between fundamental and realized niche. ▪ Distinguish between S and J population curves and explain the factors that influence which type of population curve a named population would show. ▪ Explain and give named examples of different population interactions including: competition (inter and intra-species), predation, parasitism, herbivory, and mutualism.

IB TESTING TIPS: ▪ IB often asks for named examples, be sure to use specific examples and use specific names (scientific names are not required). ▪ For example if you just say tiger this refers to 1 of 10 species versus Bengal tiger is specific to one region and one species! ▪ For a named example of a habitat or ecosystem ▪ be specific; The Giant Kelp Forest off the coast of Monterrey Bay California is much better than the beach ▪ give as much detail as possible; The Sundarbans is the largest mangrove forest in Southern Bangladesh and South-eastern India.

What is an Ecology?  The study of the living and non-living parts that interact within an ecosystem.

What is an Ecosystem?  A community of interdependent organisms and the interactions with the physical environment in which they live.  It can also be defined as the abiotic and biotic factors and the interactions between them.  The interaction between organisms and the environment is the key!

How many of these terms do you know? ▪ Organism ▪ Species ▪ Population ▪ Community ▪ Niche ▪ Habitat In your notebook draw a bunch of little organisms. Some of the same type of some of different types. ▪ Label 1 individual as an organism. ▪ Label a group of the same type of organisms (species) ▪ Circle: individuals of the same species (Population) ▪ Draw interactions between the populations (Community)

Naming Species ▪ Species: a group of the same type of organisms that is able to reproduce and produce fertile offspring. ▪ Scientific Names: used by scientists to identify a specific species. ▪ Contains two parts: Genus species ▪ Always underlined or in italics ▪ Genus always capitalized & species all lower case ▪ Examples: ▪ Homo sapiens (humans) ▪ Panthera tigeris (Bengal Tiger) ▪ Sequoiadendron giganteum (Giant Redwood) ▪ Bombus lucorum (white tailed bumblebee)

Habitat vs. Niche ▪ Habitat: where an organism lives ▪ The habitat must provide a source of food, water and shelter for the organism. ▪ Niche: the role (“job”) of the organism. ▪ This is largely to do with the trophic level of the organism. (what it eats) ▪ Examples: ▪ Plants make food for the rest of the food chain ▪ Tigers keep the population of herbivores under control

Fundamental vs Realized Niche ▪ No two species can have the same ecological niche in the same place at the same time! ▪ Fundamental Niche: the entire range of conditions in which a species could live ▪ Realized Niche: the actual conditions under which the species lives (usually due to competition)

Abiotic vs. Biotic Factors  Biotic Factors: All the living components of an ecosystem  Example: plants, bacteria, fungi, animals  Abiotic Factors: non-living, physical factors in the ecosystem that may influence an organism or a system  Examples: Temperature, salinity, pH, light,

Biotic or Abiotic? ▪ River dolphin ▪ Algae ▪ Daylight hours ▪ Precipitation ▪ Moss ▪ Soil composition ▪ Bacteria ▪ Mushroom ▪ Rocks ▪ Minerals ▪ Mangrove trees ▪ Swamp grass

Limiting Factors ▪ Factors in an ecosystem that limit the population size if there are is too much or too little of it. ▪ Sunlight ▪ Precipitation ▪ Salinity ▪ Nutrients in the soil ▪ Food ▪ Limiting factors cause a reduction in population growth as they become in short supply.

Carrying Capacity ▪ The maximum number of organisms of a single species that an ecosystem can support ▪ Population Dynamics: the study of the change in populations over time ▪ We use population graphs to look at the changes in populations over time. ▪ Sketch what a population growth curve would look like if there were no limiting factors.

Population Growth Curves ▪ Without limiting factors, there will be exponential growth (there is nothing limiting population size) ▪ Is this realistic for most populations? Justify your answer!

S-Curves ▪ Start with exponential growth ▪ Slow as they limiting factors become scarce ▪ When population reaches carrying capacity (K) there is no longer growth ▪ Where exponential growth slows until we reach carrying capacity is called environmental resistance Environmental resistance

▪ In reality populations tend to fluctuate around the carrying capacity. ▪ What is this an example of? ▪ Negative Feedback S-Curves

▪ Show a boom and bust pattern ▪ Population grows exponentially ▪ Sudden collapse called a dieback ▪ Often the population exceeds carrying capacity which is called overshoot ▪ Typical of microbes, invertebrates, fish and small mammals ▪ Can you think of any other populations that might show this type of curve? J-Curves

What type of Population Growth?

Interactions Between Organisms ▪ Through this activity you should learn about different types of interactions between organisms and how these interactions affect the populations dynamics of the organisms involved. ▪ Relationships between Organisms Class Jigsaw Activity ▪ Check your for a description of requirements!