lecture 5/12 bio

angiosperms

most abundant species rich wide-spread group of land plants characterized by flowering plants & produce seeds in a fruit

dicots

type of angiosperm that produce seeds that can split into two halves

monocots

type of angiosperm that produce seeds that cannot be split in half

root system

anchors the structure and absorbs water and key nutrients from the soil

shoot system

absorbs CO2 and sunlight from the atmosphere to produce sugars

primary growth lengthens roots and shoots, gives rise to 3 specialized tissue systems to enable

protection, food production & storage, transport

what are shoot systems specialized for absorbing?

light and CO2

what are root systems specialized for absorbing?

water and key nutrients such as N, P and K

structural features of roots and shoots

morphological diversity, phenotypic plasticity, modified roots/shoots

morphological diversity of roots

difference appearance, shapes, and structure

phenotypic plasticity of roots

root form can change in response to environmental conditions

modified roots with specialized functions

adventitious roots develop from the shoot system often function to provide added support or to permit gas exchange with atmosphere

why is there diversity of root systems observed among species that grow in the same habitat

natural selection has favored structures that minimize competition for water and nutrients

morphological diversity of shoots

allows plants to harvest light at different locations, minimizing competition and thrive in different habitats. species level variation

phenotypic plasticity in shoots

size and shape of shoot system can vary based on growing conditions (temperature, exposure to wind, availability of water, nutrients, and light. environment driven

modified shoots with specialized functions

functions ranging from water and food storage, asexual reproduction or protection. evolved a new function

transpiration

water movement through a plant and its evaporation from aerial parts (human sweating)

the leaf

is the site of majority of photosynthesis in most plants

simple leaf (morphological diversity in leaves)

petiole and a single blade

compound leaf (morphological diversity in leaves)

blades divided into leaflets

double compound leaf (morphological diversity in leaves)

large and rarely damaged by wind or rain

needle-like leaf (morphological diversity in leaves)

species from very cold or hot climate, small surface area reduced water loss through transpiration

meristems (primary growth)

populations of undifferentiated cells continuously divide to produce new cells causing plants to continuously grow

primary growth

cells that are derived from apical meristems form the primary plant body

apical meristems

located at the tip of each root and shoot, divide, enlarge and differentiate. extend plant body outward