Indicator Monday: 10/15 Why is a diet consisting of autotrophs considered beneficial?

Studying Ecology in a Habitat Levels of Ecological Organization Habitat: specific environment in which an individual lives, both biotic and abiotic elements

Populations Population size: the number of individuals present in a given population at a given time Population density: the number of individuals within a population per unit area Population distribution: how organisms are arranged

Population distribution Random distribution: no particular pattern Uniform distribution: evenly spaced throughout an area Clumped distribution: individuals arrange themselves according to availability of resources needed to survive

What effects population growth? Population growth: – Age structure: relative number of individuals at different ages – Sex ratio: proportion of males to females – Size – Density – Distribution

Population Growth Individuals added – individuals subtracted or (birthrate+immigration rate) – (death rate+emigration rate)= growth rate Growth rate x 100% = percent growth

Population growth Exponential growth: increase by a fixed percentage each year Logistic growth: growth based on carrying capacity and limiting factors Carrying capacity: the largest population a given environment can sustainably support

Population Growth Limiting factors: characteristics that limit population growth – Density dependent factor: the higher the population density, the less food and water is available, competition intensifies, predation and disease result – Density-independent factor: not influences by density, dramatic and sudden reduction in size such as flood, fire, landslide, climate change…… – Biotic potential: maximum ability to produce offspring in ideal conditions

Tuesday Trial Humans effect the carbon cycle by:

How many species do you interact with in a day? (DO NOT WRITE THIS) What did you eat? Did you step on a bug? Pet a dog? Swat a fly?

Niche Use of resources and its functional role in a community Not only the habitat where an individual lives but what it eats, how and when it reproduced, what it interacts with….. Everything an individual does and when and where it does it.

Niche Tolerance: ability to survive and reproduce under changing conditions – Specialists: low tolerance – Generalists: high tolerance

Niche Competition: multiple organisms seeking a limited resource – Intraspecific – members of the same species – Interspecific – members of different species Competitive exclusion: one species effectively competes with another so that the other is excluded from the resource

Niche Fundamental niche: without competition, a species uses entire resource Realized niche: the portion of the resources that is actually available for use – Resource partitioning: species evolve to occupy only their realized niche – Character displacement: physical evolution to meet realized niche

Wordy Wednesday Extinction: the disappearance of a species from Earth

Niche Interactions Species interact with each other in positive, negative or no effect ways. 1.Predation: an individual of one species hunts, kills and consumes an individual of another species, predator/prey 1.Population cycles alter predation 2.Evolution 3.Coevolution: two species evolve in response to changes in one another

Niche Interactions 2. Parasitism: one individual depends on another for resources, parasite/host – Symbiosis: long lasting physically close relationship where both benefit 3. Herbivory: animal feeds on a plant 4. Mutualism: two or more species benefit from a relationship

Niche Interactions 5. Commensalism: one species benefit, the other is unaffected InteractionEffect on species AEffect on species B Predation Parasitism Mutualism Herbivory Commensalim

Indicator Thursday What is the difference between artificial selection and natural selection?

Evolution and Natural Selection There are around 20 million species of living things in the world – This doesn’t account for the ones that are still undiscovered……ask Pancho! – Plants, insects, fungi, animals and the millions of bacteria

Evolution and Natural Selection Evolution: change over time. – Biological evolution is a change in a populations gene pool over time – Gene pool: all the genes present in a population – Gene: sequence of DNA that codes for a trait – F1: 40% mice brown, 60% tan – F2: 28% mice brown, 72% tan – EVOLUTION!!

Biological Evolution How? And why?? 1.Mutations: changes in the DNA Gives rise to new genetic variation Passes to the next generation

Biological Evolution 2. Migration: immigration or emigration change proportion of genes in the pool - gene flow: when migration causes specific genetic traits to change populations

Biological Evolution 3. Genetic Drift: occurs by chance - unusual event causes all but a few individuals to die, limiting the gene pool by chance

Biological Evolution 4. Natural Selection: process by which traits improve an individual’s chances for survival and reproduction. These genes are passed on to future generations

Conditions of Natural Selection Condition 1: organisms produce more offspring that can survive -Must combat limiting factors and biotic potential Condition 2: Individuals of a species vary in their characteristics -natural variations must occur: better eyesight, faster, camoflage

Conditions of Natural Selection Condition 3: individuals vary in their fitness -fitness: how reproductively successful an organism is in the environment -adaptation: a heritable trait that increases an individual’s fitness Some individuals are more likely to survive and reproduce

Conditions of Natural Selection Condition 4: Survival of the Fittest an individual with high fitness produces more offspring and passes on its genes more often than the individual with low fitness Evolution has occurred to ensure maximum success of the individual

Conditions of Natural Selection (1) Organisms produce more offspring than can survive. (2) Individuals vary in characteristics, some of which are heritable. (3) Individuals vary in fitness, or reproductive success.

Artificial Selection Selection under human direction Throughout history, humans have chosen and bred animals and plants with beneficial traits.

Speciation Process by which new species are generated Can occur in a number of different ways; the most important way is called allopatric speciation Has resulted in every form of life on Earth— today and in the past Allopatric Speciation

Speciation Allopatric: geographic isolation Peripatric: small populations in an area, no overlap breeding, genetic drift may play a role Parapatric: small populations that overlap but enough of a partial separation to keep populations separate Sympatric: no geographical isolation

Extinction The disappearance of species from Earth Generally occurs gradually, one species at a time, when environmental conditions change more rapidly than the species can adapt There are five known mass extinction events, each of which wiped out a large proportion of Earth’s species. Trilobites Marine arthropods that went extinct at the end of the Permian period.

Indicator: Friday Fodder Hey!! Something humans DIDN’T do…..at least directly. The Great Barrier Reef is being destroyed at an alarming rate. The Crown of Throne Sea Stars are responsible for 42% of it’s destruction annually. It digests the live coral and leaves a trail of white, dead coral behind it as it goes.

Indicator Monday 10/22 What can cause genetic drift of a population?