Topic 2: Ecosystems and ecology 2.1 Species and population Starter: Read the definitions your partner wrote yesterday. Do you agree/disagree with them. Discuss. https://www.youtube.com/watch?v=GlnFylwdYH4

2.1 Learning objectives Define the following terms: There are LOADS of definitions to learn today (Sorry). If you don’t understand them at the end of the lesson make sure you spend some time getting yourself familiar with them. Define the following terms: Species Habitat Ecosystem Niche Biotic and Abiotic Factors Describe the concepts of fundamental and realised niche. Explain what is meant by carrying capacity and how limiting factors affect population growth.

What is a species? In your books: Write the definition of species. Using examples explain why defining a species can be difficult. A group of organisms that share common characteristics and that interbreed to produce fertile offspring. Why can’t we use just appearance alone? Why can’t we just use genetic analysis alone?

Can be shortened to: C. auratus Which animal? Latin Binomials Carassisus auratus Genus species Can be shortened to: C. auratus When typed: italics When handwritten: underlined We must now be referring to species by their proper names. E.g. Instead of fish we must say Goldfish or Carassisus auratus Instead of fish we must say Atlantic Salmon or Salmo salar Pysgodyn aur (Welsh) Carassius (Malthese) Peix de colors (Catalan) Goudvis (Afrikaans) Guldfisk (Swedish) In your books: Explain why it is important for us to use Latin binomials.

In your books: Write the definition of habitat. Explain how to habitat of the Pacific golden plover changes through out the year. And what is a habitat? The environment in which a species normally lives. Different individuals within the same species can live in very different habitats. Habitats can change over time as a result of migration.

Aand…. What is an ecosystem? A biological community of interacting organisms and their physical environment. In your books: Write the definition of an ecosystem.

Biotic and Abiotic factors within an ecosystem Biotic Factors: The living components of an ecosystem. NOT just a list of all the living things in an ecosystem, but the roles played by each of those organisms. Abiotic Factors: The physical and chemical components of an ecosystem. In your books: Write a definition of both biotic and abiotic factors. Using the diagram to help you list the biotic and abiotic factors within specific ecosystem.

Which factors are biotic and which are abiotic? Note: Correlation NOT causation

Aaand… What is an ecological niche? A role taken by a type of organism within its community. The sum of a species' use of the biotic and abiotic recourses in an environment. In your books: Write the definition of an ecological niche. The difference between a niche and habitat: Niche is like a occupation (what an organism does), whilst a habitat is like an address (where an organism lives) Includes: Space utilisation Food consumption Temperature range Moisture requirements

Turn to the back of your books Match the key word with its definition (just letter and number) 1) Habitat A) The living components of an ecosystem. 2) Abiotic Factor B) A group of organisms that share common characteristics and that interbreed to produce fertile offspring. 3) Ecosystem C) The sum of a species' use of the biotic and abiotic recourses in an environment. 4) Niche D) The environment in which a species normally lives. 5) Biotic Factor E) The physical and chemical components of an ecosystem. 6) Species F) A biological community of interacting organisms and their physical environment. 1D 2E 3F 4C 5A 6B

Niches and competition If two species have an identical or very similar niches they cannot live in the same habitat. The Eurasian red squirrel and Eastern grey squirrel both eat very similar foods. The grey squirrel outcompetes the red squirrel.

Data interpretation: Competition The biologists Lotka and Volterra theorized that no two species with similar requirements for resources (food, shelter, etc.) could coexist in the same niche without competition driving one to local extinction. In 1930s G.F. Gause tested the Lotka-Volterra theory by growing two Paramecium species in identical conditions. However, he found that if he grew them together that only one species prevailed. In your books: Using what you know explain the findings of G.F. Gause. You must describe the trends you see in the graphs in your explanation.

Fundamental vs. Realised Niche A species may not be able to occupy its entire niche because of the presence of other species. Fundamental niche: the set of resources a population is theoretically capable of using under ideal conditions. Realised niche: the resources a population actually uses.

Case study: Joseph Connell’s barnacles Read through the information sheet. Then answer the following questions: Chthamalus Balanus What is the habitat of the two species? Why did Connell need to do both experiments to make an accurate conclusion? What information would be missing without the second experiment? Use this example to explain the differences between fundamental niche and realised niche

Carrying capacity The number of organisms a region can support without environmental degradation. (Population density or food). In your books: Describe what is happening in the graph. Use this description to help write an explanation of carrying capacity.

Interspecific relationships Inter = different Time Number of African lions Number of Thomson’s Gazelle 15 50 6 5 200 12 10 300 18 24 30 36 Examples: Predator prey relationships. Parasitic relationships. Mutualistic relationships. Each species can influence the population dynamic of other species. In your books: 1. Using the data above draw a graph of the population of the two species over time. 2. Explain the pattern in the graph.

In your books: Explain how humans have affected the carrying capacity of certain ecosystems? Try to think of how we have increased the carrying capacity of some ecosystems, not just decreased.

Limiting factors Food Space Predation Disease/Parasites J-Curve: exponential growth, no limiting factors S-Curve: logistic growth, limiting factors slow the rate of growth In your books: Draw the graph and then explain what it shows.