Chapter 13 Summary: Environmental factors and Adaptations

13.1-Survival
1. Different organisms show characteristics physiological (functional), anatomical (structural) and behavioral adaptation that enable them to survive and reproduce with changing conditions (whether external or internal)
2. LIMITING FACTOR is one environmental requirement is in limited supply effecting survival and reproduction.
3. The tolerance range of organisms effects their DISTRIBUTION (where they live)
4. Environment is made up of a ABOTIC environment which is the physical surrounding (soil, rainfall, temperature, salinity etc.) and the BOTIC environment which are other organisms which it interacts with (availability of mate, impact of predators and parasites.
5. Organisms must have access to basic requirements necessary for growth and reproduction, which is supplied by the environment
6. TOLERANCE RANGE is the range of environmental conditions (e.g. temperature) that an organism can survive in
7. ADAPTATION is an inherited characteristic that increases survival and reproduction of an individual in a particular organism, it is based on natural selection.
8. Short term adaptive changes of individuals organisms are not adaptations.
13.2-Aquatic Plants
1. Many nutrients in water, oxygen carbon dioxide, nitrogen, phosphates, chlorides, sulfates, and carbonates are dissolved in water.
2. Abotic factors are pH (level of acidity in water) mainly determined by the amount of carbon dioxide, the pH is not a important limiting factor. Oxygen can be a limiting factor as water contains less oxygen then air. Temperature is usally stable in wter and is not an important limiting factor. Light and salinity are important limiting factors in aquatic plants.
3. HYDROPHYTE (water loving) plants are plants that grow in or on water. Oxygen and light are problems, so they have abudnece of air filled spaces in their tissues, which keep them more water and oxygen supply. Other plants submerged in water have high surface area to volume ratio for gasses to easily diffuse through them.
4. Marine organisms are affected by the rise and falls of tides, salinity and type of substrate.
13.3-Extreme Terrestrial Environment
1. Animals in harsh conditions often under abotic stress their body temperature, water and salt balance needs to be regulated. Temperature is regulated by behavior, circulatory adjustments and evaporative cooling.
2. To survive harsh conditions animals go into topor or hibernation. TOPOR is when animals allow their body temperature to drop and they become inactive or dormat for a period of time, this happens in fishes, lizards, birds, bats and mice. HIBERNATION is when an animal goes into long-term topor, usaly with the onset of cold winter conditions to reduce their energy requirements triggered by scarcitiy of foods, decrease in temperature, daily light cycle change. During hibernation their is a drop of metabolic acitivty, body temperature, heart beat and respiration. There is still physiological control. Sudden or large environment changes will wake an organism from hibernation and gain heat when awoken.
3. XEROPHYTES (lovers of dryness) plants grow in hot environments. They conserve water and don’t dry out as easily. They are succulent plants or hard leaved plants. They have a thick waxy cuticle, hairs covering leafs, few stomata, low leaf surface to volume ratio, have leafs face away from sun, and some plants are naturally tolerant to salt (HALOPHYTE) which usually have high osmotic pressure in their cytoplasm, control salt level in their shoots by exclusion, shedding of leafs that are laden with salt, have salt glands and dilution of salt through growth,
4. In soil plants roots penetrate subsoil mainly to obtain water.
5. With low levels of soil nutrients, plants adapt, eg some plants before they shed an aging leaf they reabsorb remanding nutrients or by having specialised rot system to be able to extract minerals.
13.4- Major Disturbances
1. Environments can change abruptly by cyclones, landslides and fire.
2. Australian plants are well adapted to withstand the effects of fire, In eucalypts the crowns of the trees get burnt up but the fire only chars the trunk. The CAMBIUM LAYER (produces regenerative growth) is protected by bark. EPICORMIN BUDS lie under the bark of stems allowing sprouting and regrowth.
3. LIGNOTUBER is a swelling at the base of a stem that is a source of dormant buds, which rapidly regenerate.
4. Some rely on fire to crack a hard seed coat for germinate to occur.
5. Some animals die with severe fires, but some survive and as a result of the fire have increased resources.

Next up

Chapter 13 Summary: Environmental factors and Adaptations

Description

Resource summary

Similar

	Created by girlwithnosmile almost 9 years ago