IB HL Bio Unit 4

Reproductive Isolation

Members of a species may be isolated in different populations

due to various factors that prevent interbreeding. This can lead to the formation of new species.

Hybrids

reproductively sterile, cannot produce fertile offspring

Autotrophic

Generating organic nutrition from inorganic substances (Euglena)

Heterotrophic

Feeding on other organisms for food/nutrition (Dodder Vine)

Photoautotroph

Generates organic nutrition by harvesting light energy (producers)

Saprotroph

Decompose materials using external digestion (Mycelium)

Photoautotroph

generates organic nutrition by harvesting light energy (photosynthesis)

Inorganic Nutrient Cycling

Autotrophs obtain nutrients from abiotic environments, supply of inorganic nutrients is maintained by nutrient cycling

Chemoautotroph

Generates organic nutrition through oxidation of inorganic compounds and form the foundation of an ecosystem (Tube worms in hydrothermal vents)

Mixotrophic

Utilize more than one method of organic nutrition

Saprotroph

Decompose materials using external digestion (Mycelium and their hyphae)

Ecosystem

Include the biotic community and abiotic community

Capture Mark Release Formula

M*N/R; Where M is the number of marked individuals, N is the total population size, and R is the number of recaptured individuals.

Limiting factors

Anything that constraints a population size and slows or stops it from growing

Abiotic: Nutrients, water, light, space

Biotic: Food, predation, mates

Carrying Capacity

number of individuals that the ecosystem can support sustainably

Negative Feedback

A change in conditions that causes a reaction in the opposite direction. Controls population size, if it grows to quickly negative feedback brings back down.

(Blood Sugar, Pathogens)

Density Dependent factors

reduce population size when an area is too densely populated. It pushes down to carrying capacity: Wolves and Rabbits

(Drought)

Herbivory

Primary consumers ingest autotrophs

Mutualism

Two species benefit from relationship

• Clownfish and Anemone

• Zooxanthellae and Coral Polyps

Parasitism

Pathogens have specific hosts

Zoonotic

Jumps species barrier

(Coronavirus)

Invasive Species

Must out-compete or negatively affect endemic species

(Lionfish)

Allelopathy

Chemical inhibition of 1 plant by another due to the release into the environment of susbstances acting as germination or growth inhibitors

Chi Squared Test

Null Hyp: No sig difference (Random distribution)

Alt Hyp: Is significant (Associated)

Expected Frequency Formula

row total * column total all over grand total

Chemical Energy flows…

through feeding and each step, energy lost through tropic level (90%)

Units of measuring energy

KJm^’2 Year^-1

Primary Production

Biomass made by producers

Net Primary Production Formula

NPP=GPP-R (gross primary - respiration)

Secondary Production

Formation of biomass by heterotrophs

Is secondary higher than primary?

lower than primary because heterotrophs usually have high metabolic activity/ cell respiration

Oceans

Store dissolved carbon dioxide, react with water to form carbonic acid

Decomposers cycle…

Nutrients in aqautic ecosystems (filter feeders: mussels)

How does energy flow through an ecosystem

• Food energy

• Lost while flowing

• Between species

• Enters as light

• Converted by autotrophs

Percent Change formula

Final-Initial/ Initial all *100

Impacts of Farming

Soil erosion

Nutrient depletion

Carbon footprint

BOD

How much O2 is needed by decomposers in H20 to break down organic matter

Eutrophification Increases

Bioaccumulation

Absorption of toxins into organisms body over time

Biomagnification

is the process of toxins accumulate and become higher concentrated in tissues of higher trophic levels

DDT

Pesticide, accumulates in lower aquatic animals/plants

Raptors are Apex... therefore

higher food chain. DDT concentrates in bodies and weakens eggsshells of young and kills chicks

Rewilding

Restoration of neutral processes in ecosystems by positive methods