Unit Eight: Populations Notes Pt. 1: What is a Population?

1. Biological Hierarchy – The organization of Life Planet Earth Ever changing dynamic planet that has certain limitations with regards to, space, resources, biosphere… etc. Biosphere Global sum of all ecosystems Biome The interaction of living things with their environment Community A group of organisms or population of different species Population Group of organisms of one species that interbreed and live in the same time/area.

1. Biological Hierarchy – The organization of Life Organism Living things that are able to react to stimuli, reproduce, grow and maintain homeostasis Organ System A group of organs working together Organ Group of tissues in a living organism that have been adapted to perform a specific function Tissue A group of cells in an organism that have similar structure and function Cell The smallest unit of life that displays all 6 characteristics of living things Organelle A membrane bound compartment or structure in a cell that performs a special function. Molecule Atom

Largest 1. Biological Hierarchy Planet Earth Biosphere Biome Community Population Organism Organ System Organ Tissue Cell Organelle Molecule Atom The larger things are made up of the smaller things. Atoms make up molecules, molecules make up organelles, organelles make up cells… etc Smallest

2. Population Dynamics How a population changes with respect to the number and density of the organisms. Density How many organisms are living in a particular area Limiting Factors: Anything that limits population size. What might limit population size? Access to Food Predators Sunlight Space Water

2. Population Dynamics – Density Dependent Factors Factors where the effects on the size or growth of a population vary with the density of the population. Biotic factors: Food (main factor) predation, disease, migration

2. Population Dynamics –Density Independent Factors A factor that limits the size of a population whose effect is NOT dependent on the number of individuals in the population Example: An earthquake can kill all members of the population regardless if the population is large or small.

Your Turn! Take 5 minutes and make a venn diagram to compare and contrast density dependent and density independent factors.

Population Studies 1. Sample plot census: Quadrant sampling. Determines population size. Divide area into plots, randomly select plots to sample, count species in those plots Works best with stationary/slow moving organisms

Population Studies Capture – Mark – Release Used in ecology to estimate an animals population size. Portion of the population is captured, marked and released. This process is later repeated Example: Shark Week

Your Turn! Which method would you use to count the following organisms? Squirrels in the forest Capture & Release Bluegills in a lake Oak Trees in a forest Sample plot People living in the US Dandelions in a field

Population Density # 𝑜𝑓 𝑜𝑟𝑔𝑎𝑛𝑖𝑠𝑚𝑠 𝑡ℎ𝑒 𝑎𝑟𝑒𝑎 =𝑝𝑜𝑝𝑢𝑙𝑎𝑡𝑖𝑜𝑛 𝑑𝑒𝑛𝑠𝑖𝑡𝑦 How many organisms are there per area # 𝑜𝑓 𝑜𝑟𝑔𝑎𝑛𝑖𝑠𝑚𝑠 𝑡ℎ𝑒 𝑎𝑟𝑒𝑎 =𝑝𝑜𝑝𝑢𝑙𝑎𝑡𝑖𝑜𝑛 𝑑𝑒𝑛𝑠𝑖𝑡𝑦

Natality vs. Mortality Natality Birthrate Mortality Death Rate

Immigration Vs. Emigration Migration to a new place; movement of organisms Emigration Organisms moving away from natural habitat

Change in Population Over Time 𝑁𝑎𝑡𝑎𝑙𝑖𝑡𝑦+𝐼𝑚𝑚𝑖𝑔𝑟𝑎𝑡𝑖𝑜𝑛 − 𝑀𝑜𝑟𝑡𝑎𝑙𝑖𝑡𝑦+𝐸𝑚𝑖𝑔𝑟𝑎𝑡𝑖𝑜𝑛 =𝐶ℎ𝑎𝑛𝑔𝑒 𝑖𝑛 𝑃𝑜𝑝𝑢𝑙𝑎𝑡𝑖𝑜𝑛

C. Carrying Capacity The largest number of organisms that the environment can support Exponential Growth - growth whose rate becomes more rapid in proportion to the growing total number or size. Linear Growth - grows by the same amount in each time step

Unit Eight: Populations Notes Pt. 2: Relationships in Populations

1. Communities All of the biotic (living) things that live in the same region. Niche The role that a particular population serves within the community. Example: Keystone species - Wolves Habitat The environment that the population lives in.

2. Symbiotic Relationships How two organisms interact with each other Mutualism: Both species benefit Example: Bees & Flowers How? Bee’s get food Plants are pollinated

2. Symbiotic Relationships Commensalism: One species benefits, the other species is unaffected Example: Remora fish & Sharks How? Remora fish gain protection from the sharks and can feed off of the remains of meals from larger fish

2. Symbiotic Relationships Parasitism: One species benefits at the expense of the other. Example: Mosquitos How? Mosquitos suck the blood from organisms for food, depriving the host of it’s nutrients

2. Symbiotic Relationships Predator/Prey: Once species benefits by eating the other Example: Lion and Zebra How? Lion (predator) catches the zebra (prey) for food for their herd.

2. Symbiotic Relationships Invasive Species: A group of foreign organisms that is moved to another location. The new species competes with native species for resources until one of them wins. No two species can occupy the same niche. Example: Asian Carp, Sea Lamprey

Your Turn! Match the organisms to the symbiotic relationship Barnacle and whale: Commensalism Termites & Asian Carp Invasive Species Ostrich and gazelle Mutualism Mistletoe and Spruce Parasitism Wolf & Elk Predator and Prey