Ecosystems and asexual and sexual reproduction

biology unit 2

cloning

• producing genetically identical cells, groups of cells or organisms asexually

reproductive cloning

• human or other organism is produced that is identical to Foster mother

therapeutic cloning

• somatic cells nuclear transfer

• embryonic stem cells derived from therapeutic cloning can be instructed to form specialized call types such as bone marrow

• placed back in individual who gave DNA

• genetically identical to them and won’t be rejected by the donors immune system

Sexual reproduction

involves genetic contributions in the form of gametes from 2 parents from meiosis

Internal fertilization

• sperm and egg joins inside the parents bodies

external fertilization

when sperm and egg joins outside the parents bodies

advantages of internal

• higher chance of fertilization

• lower number of gametes released

disadvantages of internal fertilization

• parent much be close together

disadvantages of external fertilization

• many gametes will not survive because of predators

• eggs not protected

advantages for external fertilization

• very little energy to find a mate

• large offspring produced

biological complexity

• living organisms can be studied at different levels of complexity 2

what are examples of biological complexity

• biosphere

• biome

• ecosystem

• community

• population

• organism

Biosphere

all of earth

biomes

naturally occurring communities of flora and fauna occupying a major habitat

Terrestrial biomes

all of the climate regions in the world

ecosystem

community of living organisms that interact with each other

populations

• groups of individuals belonging to the same species and live in the shared region

organism

• and individual form of life

niche

each species has a niche in a community

• its the role is plays in a particular ecosystem

• this includes what it eats, its habitat, nesting site, and effects on other species

Energy input

every ecosystem must have a continual input of energy. This mostly involves the radiant sunlight

autotrophs (produces)

this uses photosynthesis or chemosynthesis to produce food

consumers (heterotrophs)

are organisms that receives energy by consuming the other organism

decomposes

break down organic matter into simple mineral nutrients

self sustaining systems

is a unit that is largely self sustained

trophic levels

• 1st trophic level (producer)

• 2nd trophic level (primary consumer)

• 3rd trophic level (secondary consumer)

• 4th trophic level (tertiary consumer)

• 5th trophic level (quaternary consumer)

flow of energy

• when you move up the food chain, the amount of energy passed on from each trophic level is roughly 10%

food chains depict

the flow of energy in an ecosystem

food webs

• this is when organisms after eat more than 1 plant or animal

apex predators

when organism are at the top of a food chain with no natural predators

keystone species

a species that play a crucial role in the way a ecosystem functions

• when a keystone species is removed, it may effect other species and may leading to them becoming extinct

competition

in situations where certain resources are limited, organisms complete with one another for them

examples of competition

• food

• shelter

• water

• light

2 competitions

interspecific = between different species

intraspecific = in the same species

predation

is a predator- prey relationship where the predator kills the prey for food

• predator and prey evolve together

• predator is part of the preys environment

symbiosis

prolonged relationship between species

examples of symbiosis

• Parasitism = a relationship where one species, the parasite, benefits at the experience of the other, the host

• Mutualism = an interaction between species in which both benefit

• commensalism = a relationship in which one organism benefits while the other organism is neither benefited of harmed

• amensalism = a relationship in which one organism is inhabited or destroyed whilthe e other is neither benefited nor harmed

Abundance (or density)

is defined as the number of individuals of a given species per unit area

Qualitatively

scarce, frequent, abundance

quantitatively

numbers (relating to how many animals living per square kilometre)

Distribution

clumped, uniform, random

age structure

identifies the proportion of its members that are

• pre reproductive (too young to reproduce)

• at reproductive stage

• at past reproductive stage (no longer able to reproduce)

population dynamics

the changes in population size over time which include

• birth rate

• death rate

• Migration rate

models of population growth

models of growth in closed population include:

• exponential growth model ( j - shape)

• logistic growth model ( S - shape)

limiting factors

are things that prevent a population from growing any longer

• is their is only enough food for 10 rabbits, then only 10 will survive

Density dependent

factors which impact is related to population size

• food supply, predation, disease

Density independent

factors affecting population size which are not related to population size

• bushfires, floods, salinity