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

2. 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.

3. 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

4. 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

5. 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

6. 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

7. 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.

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

9. 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

10. 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

11. 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

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

13. Natality vs. Mortality
Natality
Birthrate
Mortality
Death Rate

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

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

16. 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

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

18. 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.

19. 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

20. 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

21. 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

22. 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.

23. 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

24. 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